November 2012

NASA/TM–2012-217781

14- by 22-Foot Subsonic Tunnel Laser 

Velocimeter Upgrade 

James F. Meyers 

Analytical Services & Materials, Inc., Hampton, Virginia 

Joseph W. Lee 

Langley Research Center, Hampton, Virginia 

Angelo A. Cavone 

ATK Aerospace Systems Group, Hampton, Virginia 

Mark T. Fletcher 

Langley Research Center, Hampton, Virginia 
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November 2012

NASA/TM–2012-217781

14- by 22-Foot Subsonic Tunnel Laser 

Velocimeter Upgrade 

James F. Meyers 

Analytical Services & Materials, Inc., Hampton, Virginia 

Joseph W. Lee 

Langley Research Center, Hampton, Virginia 

Angelo A. Cavone 

ATK Aerospace Systems Group, Hampton, Virginia 

Mark T. Fletcher 

Langley Research Center, Hampton, Virginia 
Available from: 

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7115 Standard Drive 

Hanover, MD 21076-1320

443-757-5802 

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and Space Administration.
Table of Contents

I. 14-by 22-Foot Subsonic Tunnel Laser Velocimeter Upgrade I.1

Objectives I.1

Historical Background I.1

Laser Velocimetry – Its Development I.6

Figures I.11

II. Optical System Upgrades II.1

III. Laser Velocimeter Data Acquisition System – Conceptual Design III.1

System Design Using Monte Carlo Simulation III.2

The Simulator III.3

Signal Processing III.8

Example Particles III.9

Statistical Comparisons III.11

Analyzing the Statistical Results III.13

Tables III.18

Figures III.33

IV. Laser Velocimeter Data Acquisition System – Implementation IV.1

Hardware IV.1

PXI Data Acquisition System Specifications IV.1

NI PXI-1042 PXI Chassis IV.1

NI PXI-PCI8331 Interface IV.2

NI PXI-5152 High-Speed Digitizers IV.2

NI PXI-6120 Multifunction Data Acquisition Module IV.2

NI PXI-6602 Counter/Timer Module IV.3

Computer Specifications IV.3

Peripheral Components IV.4

Tektronix TDS 5054B Digital Phosphor Oscilloscope IV.4

Agilent 81150A Pulse Function Arbitrary Waveform Generator IV.5

Software IV.6

V. Laboratory Testing of the Upgraded 14-by 22-Foot Subsonic Tunnel V.1

Laser Velocimeter

Figures V.6

VI. Evaluation Testing of the Upgraded 14-by 22-Foot Subsonic Tunnel VI.1

Laser Velocimeter in the Basic Aerodynamics Research Tunnel

Evaluation of the Laser Velocimeter in Various Flow Fields VI.2

Comparison With Other Measurements VI.4

Recommendations VI.7

Figures VI.9

iii
VII. Testing the Upgraded 14-by 22-Foot Subsonic Tunnel Laser Velocimeter VII.1

– Phase II

Laboratory Investigation VII.1

Basic Aerodynamic Research Tunnel – Backward Facing Step VII.3

1.5-inch backward facing step VII.3

3.5-inch backward facing step VII.5

Comparison as normalized by step height VII.6

Flow measurements downstream of a NACA 0012 airfoil VII.6

BART test summary VII.8

Tying Up the Loose Ends VII.9

Zoom lens calibrations VII.9

Measurement volume characteristics VII.10

Flare from surfaces VII.11

Figures VII.15

References References.1

Appendices

A. Monte Carlo Simulation of a Laser Velocimeter Appendix A.1

The Monte Carlo Technique Appendix A.1

Simulation Program Data Entry Screens Appendix A.4

Screen 1: Figure A.3 – Laser Velocimeter Simulation Appendix A.4

Screen 2: Figure A.4 – LV Simulation – Transmitter Appendix A.4

Screen 3: Figure A.5 – LV Simulation – Receiver Appendix A.5

Screen 4: Figure A.6 – LV Simulation – Particles and Flow Appendix A.6

The Simulation Appendix A.10

The Laser Velocimeter Optical System Appendix A.10

Characteristics of the Collected Scattered Light Appendix A.10

The Flow Simulator Appendix A.11

Random Number Generators Appendix A.12

Particle Velocity and Trajectory Through the Appendix A.14

Measurement Volume

Signal and Data Processing Appendix A.20

Tables Appendix A.25

Figures Appendix A.30

B. Setup and Alignment of the TSI Fiberlight System for the Appendix B.1

14-by 22-Foot Subsonic Tunnel Laser Velocimeter System

Laser Safety Appendix B.1

Laser and Fiberlight System Alignment Appendix B.1

Initial Alignment Procedures Appendix B.2

Laser Velocimeter Transmission Optics and Zoom Lens Appendix B.3

Alignment

Checking Signal Levels Appendix B.6

iv
C. Data Acquisition and System Control Software - Installation Appendix C.1

and Functional Overview

Methodology Appendix C.1

Subtasks Appendix C.2

Subtasks in the LabVIEW Environment Appendix C.2

Data Management DLL (C-based Subtask) Appendix C.4

Data Acquisition and Control Program – Installation and Setup Appendix C.4

Data Acquisition and Control Program – Hardware Appendix C.5

Configuration and Data Acquisition Sequence

Program Start-Up Sequence Appendix C.7

System Power Up Appendix C.7

System Log On Appendix C.7

Mount Network Disk Drive Appendix C.8

Menu Navigation Appendix C.9

Configure System Appendix C.10

Control Scan Rig Appendix C.11

Acquire Data Appendix C.12

System Diagnostics Appendix C.13

System Information Appendix C.15

Quit Appendix C.15

Program & System Status Appendix C.15

Figures Appendix C.16

D. Data Acquisition and System Control Software – User Input Appendix D.1

and System Information Definitions

Nomenclature – Graphical User Interface Inputs/Outputs Appendix D.1

Equipment / Signals – Definitions Appendix D.2

Data Acquisition and Control Program

Configuration/Management Panel

CONFIGURE SYSTEM Appendix D.4

Select Desired Options Appendix D.4

LV Burst Signal Digitizer Management Appendix D.5

– PXI-5152 High-Speed Digitizer 

Auxiliary Channel Analog Input Appendix D.6

– PXI-6120 Multifunction Data Acquisition Module

Data Storage Management Appendix D.7

LV Data Acquisition Management Appendix D.9

Data Acquisition Conditions Appendix D.10

CONTROL SCAN RIG Appendix D.11

Scan Rig Functions Appendix D.11

Klinger MC4 Scan Rig Status Display Appendix D.13

Klinger MC4 Scan Rig Control Panel Appendix D.13

MC4 Scan Rig Position Info – Inches Appendix D.15

MC4 Scan Rig Position Info – Meters Appendix D.15

v
ACQUIRE DATA Appendix D.15

Data Acquisition Controls Appendix D.16

Data Acquisition Information Appendix D.17

System Settings Appendix D.17

Data Acquisition Panel – Current Results Tab Appendix D.18

Data Acquisition Panel – Cumulative Results Tab Appendix D.19

SYSTEM DIAGNOSTICS Appendix D.20

Data Acquisition Diagnostics Information Panel Appendix D.20

Acquired Data Tab Appendix D.20

Hardware Tab Appendix D.21

LV Burst Signal Digitizer Appendix D.21

(PXI-5152) Configuration

– High-Speed Analog-to-Digital Converter

Analog Auxiliary Signal Digitizer Appendix D.25

(PXI-6120) Configuration

– Multifunction Data Acquisition Module

System Trigger Configuration Appendix D.26

Shaft Encoder Reader Appendix D.27

(PXI-6602) Configuration

– Counter/Timer Module

Acquisition In Progress Indicator Control/Info Appendix D.28

Information Tab Appendix D.28

LV Burst Signal Digitizer Appendix D.29

(PXI-5152) Information

– High-Speed Analog-to-Digital Converter

Analog Auxiliary Signal Digitizer Appendix D.30

(PXI-6120) Information

– Multifunction Data Acquisition Module

Sub Task Info Tab Appendix D.31

Data Storage Path Generation Task Appendix D.31

– Path Generator Task Status?

Shaft Encoder Simulation Task Appendix D.31

– 1024/Rev Rotor Simulator Task Status?

Oscilloscope Trigger Out Pulse Shaping Task Appendix D.32

– One Shot Generator Task Status?

Signal Burst Simulation Manager Task Appendix D.32

– Simulation Signal Manager Task Status?

MC4 Scan Rig Management Task Appendix D.32

– Scan Rig Manager Task Status?

Log File Management Task Appendix D.33

– Log File Management Task Status?

Processed Data Management Task Appendix D.33

– Processed LV Data Manager Task Status?

Data Acquisition Monitoring Task Appendix D.33

– Data Acquisition Busy Line Status?

vi
Simulation Signal Task Info Tab Appendix D.33

Arbitrary Waveform Generator Configuration Appendix D.34

Simulated LV Signal Burst Appendix D.36

Simulation Signal Information Appendix D.36

Log File Info Tab Appendix D.37

Data Management Settings/Info Tab Appendix D.39

Data Archival Parameters/Info Appendix D.39

Data Retrieval Parameters/Info Appendix D.40

Data Retrieval/Storage Performance Appendix D.41

LV Data Handler Status Information Appendix D.42

LV Data Acquisition Results Appendix D.42

Status/Error Information Appendix D.43

Processed Results Tab Appendix D.43

LV Data Histograms Appendix D.44

Processed LV Convergence Data Appendix D.45

Processed LV Data Results Appendix D.46

System Information Appendix D.47

Quit Appendix D.48

Program & System Status Appendix D.48

Data Acquisition and System Control Software – Sub-Tasks Appendix D.49

LV Data File Name Generation Appendix D.49

File Path Structure Appendix D.50

LV Data File Structure Appendix D.51

Synthetic LV Signal Generation Appendix D.52

LV Simulation Signal Management Appendix D.52

Simulation Signal Selection Appendix D.54

Synthetic LV Signal File Format Appendix D.55

Advanced Hardware Settings Appendix D.55

Laser Velocimeter PXI-Based 

Data Acquisition Hardware Configuration Dialog 

– LV Channel (PXI-5152) Settings In Tab Appendix D.55

– Auxiliary Channel (PXI-6120) Settings In Tab Appendix D.59

– LV System Trigger Settings In Tab Appendix D.60

Scan Rig – Grid Generation Appendix D.61

Scanner Position Generator Panel

Settings Tab Appendix D.62

Active Grid Tab Appendix D.63

Complete Grid Tab Appendix D.63

Information Tab Appendix D.63

Primary Controls Appendix D.64

Scan Grid Position File Information Appendix D.65

Table Appendix D.66

Figures Appendix D.67

vii
E. Signal Processing / Data Processing Software Appendix E.1

Computed Statistics and Data Storage Appendix E.1

User Input Screen Appendix E.4

Auxiliary Programs Appendix E.8

Grwnd Appendix E.8

RunningDisplay Appendix E.8

BatchLVProcessing Appendix E.9

ConvertBinary2ASCII Appendix E.10

Tables Appendix E.11

Figures Appendix E.24

viii
14-by 22-Foot Subsonic Tunnel

Laser Velocimeter Upgrade

Objectives

The primary objectives of the upgrade of the 14-by 22-Foot Subsonic Tunnel laser 

velocimeter were to remove as many optical components as possible from the harsh 

environment in the plenum surrounding the test section and replace the dedicated signal 

processing electronics with systems that can be supported in the future. The resulting 

system must have at least the same measurement capabilities and accuracies as the 

current system. This goal was specified to yield measurements that were accurate to 

±1.5 m/s in both the U- and V-component velocity measurements. In order to meet these 

objectives the entire optics system, with the exception of the final zoom lens and pan/tilt 

mirror, would be replaced with more robust hardware that could be remotely controlled 

from outside of the plenum. Additionally the signal processing hardware would be 

replaced with high-speed analog-to-digital converters to capture signal bursts with 

processing performed by software. This would require the development of data acquisition, 

signal processing, and data processing software that would yield comparable, or better, 

real-time feedback capabilities than the original system. Further, inter-arrival time 

measurements and conditional sampling capabilities must be maintained. The overall goal 

was to develop a system that could be used by test engineers without the degree of training 

required utilize the original system, yet have safeguards in place to maintain the ability to 

obtain accurate velocity measurements.

Historical Background

In 1975 Richard Margason, Head of the Subsonic Aerodynamics Branch that operated the 

NASA Langley V/STOL Wind Tunnel (14-by 22-Foot Subsonic Tunnel), requested that the 

Gas Parameter Measurements Section (GPMS) of the Instrument Research Division (IRD) 

would design, construct and validate a laser velocimeter system capable of measuring two 

components of velocity in the V/STOL Wind Tunnel. As a first step, a proof-of-concept test 

was conducted using the two-component laboratory system developed by GPMS. The 

system was configured for coaxial-backscatter operation using a negative-positive zoom 

lens (final lens diameter of 150-mm) to obtain a focal distance of 3.87-m (tunnel 

centerline). A 15-W Argon ion laser was used in single line mode yielding approximately 

4-W at 514.5 nm. The laser beam was split into three parallel beams configured in a 

45-45 degree right triangle with the hypotenuse on the bottom parallel with the upstream / 

downstream flow of the tunnel centerline. The left beam was set to vertical polarization, 

the right beam set to horizontal polarization, and the central beam polarization set to 

45-degrees. Thus polarization separation could be used to measure two velocity 

components that are ±45-degrees to free stream. Signals from the interference of the two 

beams at the extremes of the triangle would be eliminated by the polarizing beam splitter, 

and thus not affect measurement fidelity. This configuration was successfully used in an 

investigation of the flow field above a NACA 0012 airfoil in the Langley 7-x 10-foot High 

I.1
Speed Tunnel, (Young, et al (1977), Figures I.1-I.3). However this original configuration 

did not provide the directionality capability required to fully define the flow above the 

airfoil at high angles-of-attack where the flow reversed. Thus the system was reconfigured 

by placing a single 40-MHz Bragg cell in the central beam to provide measurement 

directionality to both components to eliminate this deficiency. Unfortunately once in the 

tunnel, it was found that the Bragg effect destroyed the linear polarization of the central 

beam preventing polarization separation of the two components. Thus the velocity 

components were measured sequentially by using a remote controlled beam blocker to first 

block the left beam to allow the acquisition from the -45-degree component, then block the 

right beam to allow the acquisition of the +45-degree component. The optics system is 

shown in Figure I.4.

Bragg shifted signal bursts generated by the photomultiplier as a particle passed through 

the measurement volume, were down-mixed to 5-MHz using a double-balanced mixer and 

processed with a high-speed burst counter. The digital output from the counter was 

acquired by a prototype Laser Velocimeter Auto-covariance Buffer Interface (LVABI), a 

custom interface built by Jim Clemmons of GPMS (Meyers and Clemmons (1978), 

Clemmons (1983)). This prototype LVABI was capable of acquiring/buffering up to 4000 

velocity measurements which were subsequently transferred to a minicomputer for 

processing.

The proof-of-concept investigation was essentially a repeat of the test conducted in the 7-x 

10-foot High-Speed Wind Tunnel described above, except the model, tunnel and focal 

distances were far larger. The test was expanded to include 0.6-, 4.75-, and 19.4-degree 

angles of attack of the NACA 0012 airfoil model, Figure I.5, to provide a variety of flow 

fields for investigation. Seeding was provided by a vaporization/condensation generator 

using kerosene as the medium. The particle size distribution was measured by an optical 

particle size analyzer and found to be an exponentially shaped distribution extending to 4-

microns, Figure I.6a. The sensitivity of the LV system was determined by a Monte Carlo 

simulation (Meyers and Walsh (1974), Meyers et al (1975)) that produced the probability 

distribution shown in Figure I.6b, which when multiplied by the particle distribution 

yielded the expected measurable particle range from 2- to 4-microns, Figure I.6c. The 

measured velocity maps for the three angles-of-attack are shown in Figures I.7-I.9, 

respectively. This extensive investigation resulted in several aerodynamic and 

instrumentation papers: Two NASA Technical Notes (Hoad et al (1978), Young et al 

(1978)), One invited journal article (Meyers (1979)), One referenceable NASA Technical 

Memorandum (Hoad et al (1978)), and three conference papers (Young et al (1977), Hoad 

et al (1978), and Meyers and Hoad (1979)).

With the completion of the proof-of-concept investigation, the specifications for the 

dedicated system could be developed realistically based on the practical experiences of 

using a system in the facility. The system was to measure two components of velocity at 

focal distances from 2.4- to 7.6-m. A mechanical traversing mechanism was to be 

developed that would move the measurement volume ±1.0-m in the streamwise and 

vertical directions. Additionally a pan/tilt mirror was to be employed to align the optical 

I.2
axis along angles within ±30-degrees to the tunnel centerline and ±10-degrees about the 

horizontal plane. The measurement volume was to have a diameter of 200 microns with a 

length of 1.0 cm at tunnel centerline. 

A second proof-of-concept test was conducted to determine if the planned approach for the 

dedicated LV system would provide similar measurement quality as the previous system 

while expanding its capabilities. The primary modifications to the system were the 

implementation of the two-color approach to provide multiple measurement components 

and upgrades to the LVABI to record the inter-arrival times between particle passages 

through the measurement volume and the capability of conditional sampling (Clemmons 

(1983)). Again the 150-mm diameter zoom lens and burst counters were used. The optical 

system, shown in Figure I.10, was used to measure the wake flow downstream of a large 

NACA 0012 semi-span model. The data was lost to history primarily because this test was 

designed as a performance test of the LV and not an aerodynamic test, thus the data was 

considered unimportant. The results, however, were positive and the construction of the 

dedicated system proceeded.

The construction and testing of the system utilized the talents of several people from IRD 

and SAB. Dave Rhodes (OPMS, IRD) and Steve Jones (OPMS, IRD) performed the initial 

design of the optical system. Jim Meyers (GPMS, IRD) had the overall responsibility of the 

laser velocimeter and contributed to the final optical design along with the development of 

the signal processing and data acquisition systems, and the instrument control, data 

processing, and data display software. Tim Hepner (GPMS, Army) had the responsibility 

for the final design and construction of the LV system and developing techniques and 

procedures for its alignment. Jim Clemmons (GPMS, IRD) had the responsibility for the 

development of the advanced data acquisition hardware (LVABI). Dan Hoad (SAB, Army) 

had the responsibility for the design and construction of the LV traversing mechanism and 

the seeding system. The final system is shown installed in the V/STOL tunnel in 

Figure I.11 with Tim Hepner aligning the input optics. The key to the system was turned 

over to Dan Hoad representing the Subsonic Aerodynamic Branch and the U.S. Army in 

April 1982, Figure I.12. The representatives, from left to right, were: Dave Rhodes 

(OPMS, IRD), Tim Hepner (GPMS, Army), Jim Meyers (GPMS, IRD), Jim Clemmons 

(GPMS, IRD), Dan Hoad (SAB, Army), Bill Hunter (Head GPMS, IRD), Joe Elliott (SAB, 

Army), Bill Sellers (SAB), and Steve Jones (OPMS, IRD).

The first wind tunnel test conducted with the laser velocimeter was an investigation of the 

effects of helicopter fuselage widths and shapes and rotor-fuselage separations on timeaverage and detailed time-dependent rotor wake velocity characteristics (Hoad et al 

(1983)). Unfortunately the results of the investigation were ambiguous in that no 

apparent time-dependent velocity characteristics were observed. It appeared that the timedependency was washed out in the open-throat tunnel configuration. But this did not 

explain the lack of time-dependency in the closed test section configuration. Although 

these were the findings reported by Hoad et al (1983), they most likely were not correct. 

The determination of time-dependency was obtained from the LVABI and its samples of the 

72-per rev rotor shaft encoder. If there was time jitter in the readings, e.g. ±1 count of the 

I.3
shaft encoder, the time-dependency would be lost even if the LVABI was accurate. Even 

this was questionable given that the LVABI was a prototype and conditional sampling was 

limited to one revolution or less.

The measurement problems that were found in the 1983 rotor-craft investigation led to 

several research programs to improve measurement accuracy and conditional sampling 

fidelity. The first area to be investigated was the effect particle seeding had on the LV 

signal-to-noise ratio. The 1983 test used vaporization/condensation generators with 

kerosene as the seed material. This approach yielded a polydisperse particle size 

distribution from approximately 0.4-microns to over 5.0-microns (based on measurements 

from an optical particle size analyzer with a range from 0.4-microns to 10.0 microns), 

Young et al (1978), Figure I.6. The sensitivity of the laser velocimeter was theoretically 

calculated using the Monte Carlo simulation by Meyers and Walsh (1974) to determine the 

probability of measurement as a function of particle size, Figure I.6b, yielding the 

combined probability of measurement shown in Figure I.6c. Scattered light from the other 

particle sizes produced only system noise which degraded the velocity measurement 

accuracy. 

An investigation of the capabilities of laser velocimetry to measure turbulence intensity by 

Meyers and Wilkinson (1982) used polystyrene latex (PSL) particles for the seed material. 

These particles, 0.35-to 0.55-micron diameter spheres that form the basis of latex paint, 

were small enough to follow the turbulent flow in the 2-inch pipe used in the investigation 

yet scattered sufficient light to produce acceptable signals for a short focal length LV 

system, Figure I.13. A gallon of this material, without color or binding agents, was 

obtained from the manufacturer for evaluation. The material, 50-percent PSL by weight, 

was water suspended and could be injected into the flow with a standard paint sprayer. 

This process injected too many particles into the 2-inch pipe flow and the carrier water did 

not evaporate. A custom air-jet atomizer was developed that provided better control on the 

amount of liquid injected into the 2-inch pipe than the piston driven paint sprayer. The 

amount of PSL injected was reduced by diluting the base material. Through testing, the 

carrier with the greatest evaporation rate was determined to be a 50/50 mixture of ethanol 

and water. These changes produced LV signal bursts with very high signal-to-noise ratios 

with no noise between particle arrivals. Comparisons with simultaneous hot-wire 

measurements showed excellent LV measurement accuracies (Meyers and Wilkinson 

(1982)).

While these particles yielded excellent results with short focal length LV systems, they 

were too small to generate the scattering efficiency needed for long focal length systems. 

Larger PSL particles were available commercially, but at a prohibitive cost. With the help 

and guidance of the Chemical Engineering Department of Case Western Reserve 

University, a development program was undertaken at LaRC to manufacture PSL particles 

of a size applicable to long focal length systems. This effort led to the process developed by 

Nichols (1987) which was capable of producing monodisperse particles within a range from 

0.5-microns to 2.4-microns. Aerodynamic and laser velocimetry simulations indicated that 

particles of 1.7-microns would scatter sufficient light energy to yield good signal-to-noise 

I.4
ratios yet be small enough to faithfully follow all subsonic flows expected in the wind 

tunnel. The process produced a gallon of particles (10-percent by weight) in 24-hours, a 

sufficient production rate for wind tunnel investigations. The effectiveness of these 

particles in laser velocimeter applications was reported by Meyers (1991), Figure I.14. The 

seeding system in the V/STOL Tunnel (now renamed the 14-x 22-foot Low Speed Wind 

Tunnel), was rebuilt to provide remote scan capability that allowed the user to place the 

array of agricultural spray nozzles in the appropriate position to align the plume of PSL 

particles at the desired LV measurement location within the test section, Figure I.15.

The prototype LVABI was replaced by a commercial unit (manufactured by Macrodyne, 

Inc. under license from NASA-LaRC, Cavone et al (1987)). This unit was capable of 

acquiring up to six channels of laser velocimetry data, along with measuring the interarrival times for each channel. In addition up to 10 channels of analog and/or digital data 

could be acquired simultaneously with any LV channel or the multiple LV channel 

coincidence signal. The LVABI could acquire data, LV and/or 16-bit digital, up to 650k/s or 

12-bit analog data up to 500k/s. Inter-arrival times were measured for each velocity 

component to a resolution of 0.1-microseconds up to a maximum time of 0.65 seconds 

(resolution drops to 1.0 μsec after 6.5 msec and 10 μsec after 65.5 msec). Each channel had 

a separate on-board memory of 16,384 16-bit words. Upon completion of a data acquisition 

sequence, the data was transferred via 16-bit data bus with Direct Memory Access (DMA) 

to the Hewlett-Packard model 1000 minicomputer for processing and real-time display of 

the statistics and velocity histograms.

The capabilities of the upgraded systems were determined with the investigation of the 

inlet flow to a helicopter rotor (Hoad et al (1988), Elliott et al (1988), Meyers (1988)). Maps 

of the entire velocity field were to be obtained at various rotor azimuth angles. Thus 

conditional sampling was required along with inter-arrival time measurements to 

determine if successive measurements occurred during the same revolution or a 

subsequent revolution. Sampling bias considerations required that only one measurement 

should be made at a given rotor azimuth per revolution. Thus redundant measurements 

were eliminated. The remaining measurements in each 3.0-degree azimuth angle wedge 

were thus independent and were statistically analyzed to yield the velocity maps. Example 

velocity maps of the inlet flow are shown in Figure I.16. The results obtained in this 

investigation demonstrated the capabilities of the laser velocimeter and proved that the 

system was ready for use as a flow diagnostic tool in the 14-by 22-Foot Low Speed Wind 

Tunnel, Figure I.17.

The advances in micro-electronics during the 1980's led to the possibility of replacing the 

high-speed burst counters with frequency domain signal processing systems. The increase 

in measurement accuracy was demonstrated by Meyers and Clemmons (1987) and Meyers 

and Stoughton (1988). This research led to a United States patent (Meyers et al (1988)) 

and the development of a commercially built frequency domain signal processor 

(manufactured by Macrodyne, Inc. under license from NASA-LaRC, Meyers and Murphy 

(1990)). The theoretical predictions that frequency domain processing would be more 

accurate than high-speed burst counters were proven experimentally by Hepner (1994). 

I.5
During the early 1990's three frequency domain signal processors were obtained from 

Macrodyne and incorporated into the laser velocimeter system, replacing the high-speed 

burst counters. Also during this time period a third optical component was added and 

located below the test section floor, Figure I.18. The system could be operated in either the 

two- or three-component configuration depending on the requirements of the flow field 

investigations. The system remained in this configuration until the current effort began.

Laser Velocimetry – Its Development

The Laser Doppler Velocimeter (LDV), also known as the Laser Doppler Anemometer 

(LDA) was first developed in 1964 by Yeh and Cummins (1964). They used the principles 

found in RADAR where Doppler shifted scattered radiation from a moving target was 

combined with a reference signal and passed to a square-law detector where the two 

signals heterodyned. The output signal from the detector contained the original two 

frequencies, their sum and difference. Low pass filtering yielded the difference (Doppler) 

frequency that could be measured using a frequency discriminator. Since RADAR systems 

were normally used in a coaxial backscatter configuration, multiplying the measured 

Doppler frequency by the wavelength of the transmitted radiation yielded the velocity of 

the target along the axis of the transmitted radiation. Yeh and Cummins (1964) passed a 

He-Ne laser beam through a water flow in a glass pipe using the optical configuration 

shown in Figure I.19. As shown in the figure, a portion of the forward scattered light was 

collected and passed toward a photomultiplier along with a portion of the transmitted laser 

beam. The photomultiplier served as both the square-law detector and low-pass filter 

(200 MHz) to yield an electronic signal with the Doppler frequency biased by a DC level. 

This reference-beam configuration produced the first flow velocity measurements using 

laser light.

This development at Columbia University, funded by a grant from NASA – Marshall Space 

Flight Center, had the goal of developing a method that could be expanded to measure 

three component velocities in a supersonic wind tunnel. The technology was transferred to 

NASA where it was entrusted to Brown Engineering to develop further. This research led 

to the first ever LDV measurements of an air flow (Foreman et al (1965)). However, the 

effort also showed the necessity to maintain absolute optical alignment in order to obtain 

successful measurements. Thus the technology was transferred to Raytheon where 

hardened single-component and three-component systems were developed (Fridman et al 

(1969), Huffaker et al (1969), and Huffaker (1970)). Signal processors based on RADAR 

and FM radio technology were developed by Raytheon to operate in the expected Doppler 

frequency range (Fridman et al (1969)). A schematic of the optical system is shown in 

Figure I.20 and a photograph of the system being used to measure the flow in a high-speed 

jet is shown in Figure I.21.

After seeing the problems involved in maintaining the optical alignment, Goldstein and 

Kreid (1967) from the University of Minnesota reasoned that if the laser beam was split 

into two parallel beams that were crossed by a lens, one with 99-percent of the optical 

energy and the second with 1-percent, light scattered by particles passing through the 

I.6
common volume would have a portion that would be aligned with the other beam. Thus by 

placing the photomultiplier along the axis of the low energy beam, scattered light from the 

high-energy beam would be automatically aligned and the problems with optical alignment 

sensitivity would be solved. A schematic of the configuration is shown in Figure I.22.

The breakthrough by Goldstein and Kreid led to the nearly simultaneous development of 

the dual-scatter configuration in Germany (Lehmann (1968)), France (vom Stein and 

Pfeifer (1969)), England (Rudd (1969)), and the United States (Brayton (1969), Brayton & 

Goethert (1970)). Instead of a 99:1 split of laser energy, a 50:50 division evolved in these 

systems and was used with the scattered light collecting optics placed between the two 

laser beams. The scattered light obtained from both beams heterodyned on the 

photocathode surface of the photomultiplier with the cross-beam angle maintained in the 

scattering geometry (Meyers (1971)), so the Doppler shift was constant regardless of the 

width of the collecting lens or its location in space. A schematic of the configuration is 

shown in Figure I.23, and the relationship between the Doppler frequency and the particle 

velocity is given by:

(1)

where V is the particle velocity, λ is the wavelength of the laser light, fD is the Doppler 

frequency, and θ is the angle between the two crossing laser beams.

Through experimentation researchers later reasoned that because laser light is coherent, 

the crossing of the two laser beams would produce interference fringes (Lennert et al 

(1970)), Durst and Whitelaw (1971)). The spacing between adjacent fringes can be 

determined from:

(2)

where lf is the fringe spacing, λ is the wavelength of the laser light, and θ is the angle 

between the two crossing laser beams. A schematic of the interference fringes and their 

physical dimensions is shown in Figure I.24, and a photograph of the cross section of the 

fringes is shown in Figure I.25. A schematic of this cross section is shown in Figure I.26 

along with representative signals obtained by particles passing through the fringes at 

various trajectories. The frequency of the scattered light could then be multiplied by lf to 

obtain the velocity of the particle – the same relationship as the Doppler model, 

equation (1).

Later improvements to the optical configuration included techniques to measure two 

velocity components using polarization (Lennert et al (1970, 1972)) and color (Grant and 

Orloff (1973)). The inability of the technique to measure velocity directionality was 

I.7

V=

λ f D

2sin (

θ

2

)

l f=

λ

2 sin(

θ

2

)
overcome by Mazumder (1970) through application of a rotating diffraction grating to shift 

the optical frequency of the two focusing laser beams in opposite directions. This approach 

artificially introduces an apparent velocity in the Doppler model by adding a fixed 

frequency bias in the frequency fD, equation (1). Subtracting the value of this bias 

eliminates the directional ambiguity, provided all Doppler frequencies are less than the 

bias frequency. In the fringe model, the addition on the bias frequency results in moving 

fringes. Again subtracting the bias frequency will eliminate the directional ambiguity. 

Mazumder (1970) was also attempting to use a crystal Bragg cell to perform the same 

function as the rotating grading. This work led to the current use of Bragg cells in all LDV 

(or fringe-type laser velocimeters – if the optical interference model is preferred) optical 

systems. The final component that led to the current state-of-the-art optical systems was 

the use of polarization preserving fibers to separate the laser from the transmission optics 

(Dyott (1978), Sasaki et al (1980), and Knuhtsen et al (1982)).

Although all of the developments described above are used in the current state-of-the-art 

LDV optical systems, their configuration is far different than the earlier systems. The two 

primary changes were the placement of the Bragg cell(s) and the polarization preserving 

optical fibers. Originally a Bragg cell was placed in one of the two laser beams defining a 

given measurement component to offset the Doppler frequency of that component. 

However, Rhodes (1976), and Gartrell and Jordan (1977) used a two-dimensional water 

Bragg cell to divide a single laser beam into four beams forming a square. The left two 

beams were shifted 15 MHz from the right two beams, and the upper beams were shifted 

25 MHz from the lower beams. Thus the Bragg cell not only split the input laser beam into 

the needed four beams for two-component measurements, but Bragg shifted each pair by a 

different amount so that the acquired signal frequencies obtained from a single 

photomultiplier could be separated by band-pass filters. Although there is no apparent 

traceability to this earlier development, current LDV optical systems use a single crystal 

Bragg cell to split the input all-lines Argon ion laser beam into multiple beams separated 

by color and the Bragg effect. The colors can be separated since the Bragg scattering angle 

is dependent on the wavelength of the incoming light. The cell orientation and RF drive 

power is set to equalize the energies of the zero and first order diffracted beams. Mirrors 

are then used to select the desired beams and direct them to optics that will pass the light 

to its respective polarization preserving fiber. The polarization preserving fibers are now 

used to transmit each of the four laser beams respectively, to the focusing optics instead of 

being used to transmit light energy between the laser and the splitting optics. 

Signal processing technology translated from general purpose instrumentation to 

specifically designed instrumentation is now back to general purpose instrumentation. 

The original signal processor was an analog scanning spectrum analyzer and acquisition 

consisted of visual observations. The first real signal processor was a frequency tracker 

developed by Raytheon (Fridman et al (1969)). This modified RADAR frequency tracker 

was basically an FM radio with an analog feedback loop to hold the intermediate frequency 

(IF) constant during periods of signal dropout. After a user-selected period of time, the 

tracker will begin a search in an attempt to reacquire the signal frequency. Since the 

minimum duty cycle (fraction of time a signal MUST be present) was 15-percent, a very 

I.8
high seeding density was necessary and since the occurrence of particles in the 

measurement volume is random, the technique was not practical for gas flows.

This problem was addressed at the first ever conference on laser Doppler velocimetry held 

in March 1972 at Purdue University. A lively continuing discussion of the virtues of 

processing in the time domain versus the frequency domain extended over the course of 

the entire meeting. The characteristics of frequency domain signal processing were 

addressed by Milt Huffaker (NASA – Marshall) and Jim Meyers (NASA – Langley). The 

advantages included available hardware (frequency tracker) and continuous signals whose 

amplitudes were proportional to velocity – provided the duty cycle was high. The primary 

disadvantages were the high signal-to-noise ratio required and signal dropout not clearly 

defined in the output. There was also a concern that time-of-flight broadening (short burst 

lengths leading to a broadening of the frequency peak) produced measurement 

inaccuracies. The characteristics of time domain signal processing were addressed by Andy 

Lennert, Don Brayton and Les Crosswy (USAF – AEDC), Jeff Asher (General Electric), 

and Hans Pfeifer (ISL – France). The advantages of time domain processing were the 

ability to measure the Doppler frequency from a single particle passage through the 

measurement volume, and lower signal-to-noise requirements. Roy Pike (Royal Radar 

Establishment – England) proposed using photon correlation to determine the Doppler 

frequency from very low signal levels, down to photon resolved. While the technique was a 

time domain approach, it required contributions from many signal bursts in order to build 

up the correlogram. The disadvantages of the time domain approach included the 

development of multiple approaches with no clearly superior method, and the limited 

sampling clock frequencies and processing speed of the then state-of-the-art analog-todigital converters and digital electronics, respectively.

During the next several years LDV signal processing aligned to a single direction. In the 

frequency domain, only four Raytheon frequency trackers were built (three for NASA – 

Marshall and one for NASA – Langley) because the capabilities did not justify the high 

cost. Later DISA Electronics (now Dantec) constructed a commercial unit using similar 

technology for liquid flow applications with lower signal frequency limits that reduced the 

cost to reasonable levels. Thermo Systems (now TSI) constructed a commercial unit using 

a digital feedback loop which reduced the minimum duty cycle to 1-percent. While a major 

improvement, it was still used mainly for liquid flow applications. In the time domain, 

photon correlation (Pike (1972)) was used when signals were photon resolved because of 

long focal length, limited laser power, and/or small collecting lenses. The correlators were 

custom built by Malvern Instruments in England. Unfortunately they used antiquated 

RTL circuits and the units were quite expensive. Their approach was to use AND gates to 

compute a single-bit correlation. This provided relatively high-speed processing, but the 

number of components involved resulted in limiting the correlogram to only 99 delay 

times. While the approach allowed the measurement of reasonably high Doppler 

frequencies, it required more signal bursts to reach a stable correlation than multi-bit 

correlation – thus only average velocity measurements were possible.

The time domain technique that had the greatest promise was the high-speed burst 

counter. In order to measure the relatively high Doppler frequencies obtained from air 

I.9
flows there were several approaches used. The counter developed at the USAF Arnold 

Engineering and Development Center (AEDC) used pulse stretching techniques to allow 

more reference clock pulses to be counted within the data burst (Brayton et al (1972)). At 

Brown Boveri in Switzerland an analog/digital counter was developed to measure the zero 

crossing time of the central cycle (Iten and Mastner (1974)). The counter developed at 

General Electric was another analog/digital counter, but used the entire signal burst to 

make the measurement (Asher (1972)). The GE developed technology was later 

transferred to Macrodyne who then constructed a counter for NASA – Langley. Macrodyne 

redesigned the GE counter to be pure digital using TTL logic with a 125 MHz clock and a 

maximum signal frequency of 25 MHz. These circuits were upgraded to ECL logic in the 

second generation counters, available in the mid 1970s. A pure digital counter was also 

constructed at the Institute Saint Louis in France using two counters to measure the time 

for two different number of signal cycles simultaneously (vom Stein and Pfeifer (1972)). 

By the end of the 1970's both DISA (now Dantec) and TSI were also making pure digital 

counters and digital counters remained the standard until the early 1990's when digital 

circuits became fast enough to perform FFTs of a single burst in the frequency domain 

(Meyers and Stoughton (1988) and Meyers and Murphy (1990)). Currently frequency 

domain processors performing FFTs in hardware are available from several sources, 

notably Dantec. Time domain processing using high-speed digital circuitry to employ 

correlation techniques is available from TSI. Both systems have similar measurement 

accuracies and costs.

Although not fully appreciated at the time, even by the presenter, a presentation at the 

1975 Minnesota Symposium on Laser Anemometry opened the door to the future (Griskey 

et al (1975)). Griskey was primarily presenting a method to automatically scan the LDV 

measurement volume throughout a water flow in a 2-inch pipe, when he gave a glimpse 

into the future by stating that his data was acquired by capturing each signal burst in its 

entirety using a “high-speed” (5.0 MHz) 8-bit waveform recorder with a register length of 

2048 samples. These signal traces were transferred to a minicomputer for processing using 

FFT techniques. He stated that it took a long time to process a data ensemble, but the 

results were very good. Only a few attendees grasped the significance of this revelation, 

and even those did not pursue the technology, and Griskey's work was lost to history. It 

was another 15 years before FFT-based instrumentation was developed and shown to be 

superior to high-speed burst counters. And only now, some 35 years after Griskey's 

revelation, the integration of modern electronics with software algorithms will facilitate 

the application of his concepts to production testing.

Further detail on the laser Doppler velocimetry technique can be found in Laser Doppler 

and Phase Doppler Measurement Techniques by Albrecht, H. E.; Borys, M.; 

Damaschke, N.; and, Tropea, C. (2003), and the Springer Handbook of Experimental 

Fluid Mechanics, Tropea, C.; Yarin, A. L.; and Foss, J. F. (Eds), (2007).

I.10
Figure I.1.- Two component laser velocimeter installed in the 7-x 10-foot High-Speed Wind Tunnel.

Figure I.2.- NACA 0012 airfoil installed in the 7-x 10-foot High-Speed Wind Tunnel.

I.11
Figure I.3.- Laser velocimeter measurements of the flow above a NACA 0012 airfoil at 19.4-degrees angle-ofattack.

Figure I.4.- Two-component laser velocimeter installed in the V/STOL Wind Tunnel.

I.12

VT
Figure I.5.- NACA 0012 airfoil installed in the V/STOL Wind Tunnel.

Figure I.6.- Probability of a successful measurement as a function of particle size.

I.13

1.0

0.5

0

0 1 2 3 4 5

Diameter of seed particle, m μ

(a) Particle size from smoke generator.

1.0

0.5

0

0 1 2 3 4 5

Diameter of seed particle, m μ

(c) Probability of successful velocity measurement

for seed from smoke generator.

1.0

0.5

0

0 1 2 3 4 5

Diameter of seed particle, m μ

(b) Probability of successful velocity measurement

for a given particle size.

Probability density function normalized to peak
Figure I.7.- Laser velocimeter measurements of the flow above a NACA 0012 airfoil at 0.6-degrees angle-ofattack.

Figure I.8.- Laser velocimeter measurements of the flow above a NACA 0012 airfoil at 4.75degrees angle-ofattack.

Figure I.9.- Laser velocimeter measurements of the flow above a NACA 0012 airfoil at 19.4-degrees angle-ofattack.

I.14
Figure I.10.- Upgraded proof-of-concept laser velocimeter.

Figure I.11.- Completed laser velocimeter being aligned by Tim Hepner (GPMS, Army).

I.15
Figure I.12.- “Official” turn-over of the laser velocimeter to the Subsonic Aerodynamics Branch.

Figure I.13.- Polystyrene latex (PSL) seeding in the jet exiting a 2-inch pipe.

I.16
Figure I.14.- Microscope photographs of PSL microspheres, 2000x.

Figure I.15.- PSL particle generator traversing mechanism in the V/STOL settling chamber. 

I.17

0.6 microns 1.0 micron

1.7 microns 2.0 microns

2.7 microns
Figure I.16.- Freestream removed vertical-component of velocity 1.0 chord above the rotor disk.

Figure I.17.- Laser velocimeter during routine rotorcraft testing.

I.18

-1.0 -0.5 0 0.5 1.0

r/R

1.0

0.5

Air Flow

-0.5

-1.0

-1.0 -0.5 0 0.5 1.0

r/R

1.0

0.5

-0.5

-1.0

Air Flow

1.0

0.5

Air Flow

-0.5

-1.0

-1.0 -0.5 0

r/R

0.5 1.0

1.0

0.5

Air Flow

-0.5

-1.0

-1.0 -0.5 0 0.5 1.0

r/R

-1.0 -0.5 0

r/R

0.5 1.0

1.0

0.5

Air Flow

-0.5

-1.0

-.03 -.02 -.01 0 .01 .02

Normalized V-component velocity

Azimuth = 0.0 degrees Azimuth = 22.5 degrees

Azimuth = 45.0 degrees Azimuth = 67.5 degrees

Azimuth = 90.0 degrees
Figure I.18.- Laser velocimeter expanded to three-components.

I.19
Figure I.19.- Laser Doppler velocimeter (reference beam) developed by Yeh and Cummins in 1964.

I.20

MIRROR

MIRROR

PMT

BEAMSPLITTER

TO

ELECTRONICS

LENS 2

LENS 1

V

FLOW TUBE

LENS

BEAM FROMLASER
Figure I.20.- Three-component LDV (reference beam) developed by Fridman et al for NASA - Marshall.

Figure I.21.- Three-component LDV (reference beam) measuring the flow in a supersonic jet.

I.21

Photomultipliers

Photomultiplier
Figure I.22.- Cross-beam, reference-beam LDV developed by Goldstein and Kreid (1967).

I.22

MIRROR MIRROR

PMT

BEAMSPLITTER

TO

ELECTRONICS

LENS 2 LENS 1

V

FLOW TUBE

PIN HOLES

LASER

BEAM FROM
Figure I.23.- Cross-beam, dual-scatter LDV developed by multiple researchers (1968-1970).

I.23

MIRROR

PMT

BEAMSPLITTER

TO ELECTRONICS

LENS 2

LENS 1

V

FLOW TUBE

PIN HOLE

BEAM FROMLASER
Figure I.24.- Schematic of the interference fringes produced by a cross-beam LDV.

Figure I.25.- Photograph of the cross section of the interference fringes produced by a cross-beam LDV.

I.24

Y

Gaussian Radial

Intensity Distribution

Bright Fringes

l =f

λ

2 sin ( )θ

2

Z

X

1

1/e2

D = bw

4 F λ 

π d

L = mv sin ( )θ

2 Dbw

Wavefronts

X

1/e Relative Beam

Intensity

2

λ

θ
Figure I.26.- Schematic of signals that would be generated by various particle trajectories through the 

interference fringes in the cross-beam LDV.

I.25

Z

1

2

3

4

1

2

3

4

β4

β3

Y

1/e and 1/e Relative

Beam Intensity and Relative

Peak Fringe Intensity Contours

2

Pedestal

1

2

3

4

1

2

3

4
I.26
Optical System Upgrades

The primary concerns with the current laser velocimeter optical system were focused on 

the influences that changes in temperature, flow buffeting, and tunnel vibration had on 

optical alignment, and also on the difficulty in aligning the system to obtain the maximum 

possible data rate. The objective was to remove as many of the optical components from 

the plenum area as possible and place them in a more environmentally friendly location 

that was offered by the stability typical of a laboratory environment.

Advances in polarization preserving single-mode optical fibers have increased optical 

transmission efficiency and reduced the losses that result from Brillouin scattering, a time 

dependent relative change in index of refraction caused by the transmitted laser beam. 

These modern fibers offer the ability to transmit higher optical powers over greater 

distances than their predecessors making their use a viable alternative to a free-space LV 

optical configuration. Manufacturers of laser velocimetry hardware have developed 

systems that utilize these new optical fibers to transmit the conditioned and frequency 

shifted output beams to the focusing lens using a pair of polarization preserving fibers for 

each velocity component. Additionally they have developed an optical system that uses a 

single Bragg cell to separate the colors in the all-line input laser beam, split each color to 

obtain the pair of beams needed for each measurement component, and impose a 40 MHz 

Bragg shift on one beam of each pair. This degree of integration greatly reduces the 

complexity of the transmission optics making the system more robust and easier to adjust 

in order to obtain and maintain the needed alignment tolerances. The scattered light 

collected from the particles passing through the measurement volume is transmitted to the 

color separation optics and photomultipliers via a multi-mode optical fiber. These new 

systems have reduced the need for sophisticated traversing mechanisms designed to move 

heavy optical systems including the laser. Additionally, these systems allow the primary 

optical components along with the laser to be separated from the test environment.

An updated LV system was designed based on this new technology that replaces all of the 

current optical components except for the large zoom lens and the pan/tilt mirror. The 

optical components along with some custom electronics were obtained from TSI, Inc. Once 

the various components were procured and delivered, laboratory testing was conducted to 

answer the primary questions:

1) Could the new transmission optics be used at the laser power levels needed for 

long-focal length applications?

2) Were the transmission efficiencies of the optical fibers sufficient to yield the 

needed laser power at the distal end of 15-meter long fibers?

3) Were the signal-to-noise ratios and signal levels sufficient to yield accurate 

measurements from 1.7-micron PSL particles at a focal length of 4-meters?

To answer these questions a laboratory investigation was conducted using the new optical 

system coupled to the zoom lens from the current 14-by 22-Foot ST laser velocimeter. The 

II.1
laser was set to an all-lines output power of 5.0 W. An etalon was not used in the laser. 

The optical power exiting the polarization preserving fibers was 300 mW in each green 

beam (514.5 nm) and 280 mW in each blue beam (488.0 nm). The Monte Carlo simulation 

(Chapter III and Appendix A) predicted that these optical powers would yield acceptable 

signals from 1.7-micron PSL particles at the 4.0 m focal distance needed to reach the 

center-line of the 14-by 22-Foot Subsonic Tunnel. The first test used a Royco particle 

generator to provide a low-speed flow containing 2.0-micron PSL particles to determine the 

signal strength and quality at various injection points and flow angles with respect to the 

measurement volume. The signal levels and qualities were comparable to predictions and 

were sufficient to yield accurate velocity measurements. As expected reducing the particle 

size to 1.7-microns yielded signals that were still acceptable. A wind tunnel test was then 

simulated by using the LV to measure the flow at several locations within the jet exiting a 

2-inch pipe. A six-nozzle atomizer was used to inject 1.7-micron particles into the inlet of 

the blower that provided a 50-m/s flow exiting the 2-inch pipe. The acquired signal levels 

were identical to those obtained from the Royco test using the same particles. Data rates 

and measured flow statistics were as expected based on previous measurements using 

Doppler global velocimetry (DGV) and point Doppler velocimetry (pDv).

The laser input side of the Fiberoptic LDV system, Figure II.1, is to be located in the 

environmentally controlled laser laboratory adjacent to the test section of the 14-by 

22-Foot Subsonic Tunnel. Thus this portion of the LDV is isolated from the effects of 

tunnel buffeting, environmental temperature and pressure changes, and vibration. It 

consists of the laser, turning mirrors, the TSI Fiberlight and optical fiber couplers. The 

Figure II.1.- Laser and optical fiber coupler system – to be installed in the laser laboratory adjacent to the 14-by 

22-Foot Subsonic Tunnel test section.

II.2
multi-wavelength input laser beam passes through the Fiberlight and is separated into two 

pairs of laser beams (488.0 nm and 514.5 nm) with each pair consisting of an unshifted 

beam and frequency shifted beam. The four beams are directed into individual optical 

fiber couplers where each beam is focused onto the end of a single mode, polarization 

preserving fiber and delivered to the transmit/receive fiber optic probe located in the 

plenum area about the test section of the 14-by 22-Foot Subsonic Tunnel.

Once the laser beams are delivered to the transmit/receive probe located within the tunnel 

plenum area, the four individual laser beams exit the fiber optic cables where they are 

re-collimated into parallel 2.5 mm-diameter beams within the probe. The four beams 

exiting the probe are arranged in an orthogonal pattern with the 488.0 nm beams located 

in the horizontal plane and the 514.5 nm beams located in the vertical plane. These laser 

beams are directed via turning mirrors to the two element zoom lens where they are 

focused at a desired location within the wind tunnel test section, Figure II.2. The 

characteristics of the zoom lens and the resulting measurement volume, where the four 

beams cross, are determined in Chapter VII.

Figure II.2.- Transmit / Receive Optical System – to be installed within the plenum area about the 14-by 22-Foot 

Subsonic Tunnel test section.

When particles pass through the measurement volume, a portion of the light scattered 

from those particles is collected in the backscatter direction by the zoom lens. Since the 

laser beams entering the zoom lens are collimated and parallel, the collected scattered light 

exiting the negative lens is collimated. It is then directed via the turning mirrors to the 

II.3
transmit/receive probe. The collecting lens on the probe focuses the collected scattered 

light onto a multi-mode optical fiber located at the rear of the probe. This fiber directs the 

light to the photo detector module located in the laser laboratory, Figure II.1. This module 

chromatically separates the collected scattered light, directing each wavelength to its 

respective photomultiplier to obtain the U- and V-component signal bursts which are then 

transmitted via coaxial cable to the data acquisition electronics.

The details for configuring and aligning the optics system are given in Appendix B.

II.4
Laser Velocimeter Data Acquisition System

Conceptual Design

The concern that the Frequency Domain Signal Processors utilized electronic components 

that were no longer available with no potential replacements would put wind tunnel 

testing at risk necessitated the replacement of the signal processors with something that 

could be supported. There were two potential approaches to their replacement. The 

obvious approach would be to replace the signal processors with devices affording similar 

functionality at a cost of approximately $40-50k per component. This approach would also 

require the re-engineering of the LVABI to utilize supported electronic components to 

provide the needed measurement capabilities, e.g., inter-arrival time measurements and 

conditional sampling.

An alternative option would be to use modern electronics and computers to implement the 

method first used by Griskey et al (1975) where he used a Biomation 805 waveform 

recorder to capture the signal bursts from a fringe-type laser velocimeter. After each signal 

burst was captured, the waveform was transferred to a minicomputer where it was 

analyzed using FFT techniques to determine the signal frequency, and thus the velocity of 

the particle that generated the signal burst. The technique proved to be very accurate 

because it used more information from the signal burst than the start/stop point of the 

then state-of-the-art signal processors – the high-speed burst counters. However because 

of the limited capability of electronics and computer technology in 1975, the approach was 

only useful for stable liquid flows because of the limited sampling frequency (5.0 MHz) of 

the waveform recorder and the time required to process each signal burst.

In the last 35 years high-speed electronics and computer technology have improved to the 

point where Griskey's method may now be a viable alternative for laser velocimetry data 

acquisition and signal processing, even for production testing in a wind tunnel. 

Additionally, the costs of implementing this approach using Commercial Off The Shelf 

(COTS) hardware are so low that the entire data acquisition system is cheaper than a 

single custom signal processor available from today's laser velocimetry system 

manufacturers, and could produce measurements with better precision. The challenge was 

to develop a system that maintained the capabilities of the current system, yet hopefully 

have additional capabilities and produce better measurement precision. Thus the design 

specifications include the following requirements:

1) Acquire and process signal bursts from two velocity components at rates that 

exceed the seeding arrival rates in the facility (with an option for the addition of 

the third velocity component);

2) Develop and implement a scheme which eliminates spurious signals or signal 

bursts with poor signal-to-noise ratios or inconsistent signal frequencies within 

the burst;

3) Provide the capability to enforce coincidence on the two velocity components;

4) Measurement precision of 0.2-percent of reading, e.g., 1.0 m/s for a velocity of 

III.1
100.0 m/s and a Bragg shift of 40 MHz at tunnel centerline;

5) Measure the times between successive signal bursts (interarrival time);

6) Measure the rotor azimuth angle when each signal burst is acquired (conditional 

sampling);

7) Measure other selected parameters when each signal burst is acquired 

(conditional sampling);

8) Provide real time storage for at least 1000 signal frequency / velocity 

measurements per acquired ensemble; and,

9) Provide near real time display of ensemble statistics and velocity distributions.

The advantages of this approach were lower cost, flexible processing (since the processing 

would be done in software), easier to update and support, and potentially provide more 

accurate measurements. The primary disadvantage was whether acceptable data 

acquisition rates could be obtained.

In order to determine if the COTS / software approach would support the required 

capabilities, Monte Carlo simulation technology (Meyers and Walsh (1974)) was used to 

model the optical system and generate realistic signals that could be used to test and 

evaluate various data processing schemes. If a data processing scheme could be developed 

with accuracies equal to or better than hardware solutions with acceptable data processing 

times, the COTS / software approach would be a viable solution worth pursuing. The 

simulated signals could also be converted to electronic signal bursts using an arbitrary 

waveform generator. These electronic signals would be photon resolved with known signal 

frequencies that could be used to test and evaluate the data acquisition hardware and its 

influence on data processing time and measurement accuracy. The Monte Carlo simulation 

could also provide evaluation and optimization of the proposed upgraded optical system 

prior to laboratory testing.

System Design Using Monte Carlo Simulation

Monte Carlo simulation provides a direct path from selected flow field characteristics to 

particle selection and its trajectory through the measurement volume to the generation of 

the resulting signal burst. The simulation provides a dynamic range from photon resolved 

signals to full photomultiplier saturation while maintaining the Poisson statistics of the 

collected scattered photons from a particle passing through the laser velocimeter 

measurement volume as defined by the input optical system characteristics. The signal 

burst could then be processed by candidate techniques and algorithms and the result 

evaluated based on the known velocity of the particle that generated the signal. Although 

the specifics of the Monte Carlo simulation are presented in Appendix A, the applicability 

of this technology is easier understood by following an example particle from selection to 

the presentation of the resulting signal burst to the signal processing algorithms. Along 

with the text below, the logical path of the process may also be followed with the flow 

diagram presented in Appendix A.

III.2
The Simulator

Once started, the simulator requests the user to input the characteristics for a twocomponent, two-color laser velocimeter optical system. These user inputs include: 

(examples from the Basic Aerodynamic Research Tunnel (BART) configuration, 

Figure III.1, presented in the units needed by the program)

Transmission optics:

Focal distance of the transmitting lens in meters

Focal distance: 4.36 m

Diameter of the laser beam at the focusing lens in meters

Diameter: 0.02 m

X and Y location of each of the four transmitted laser beams about the center of the 

transmitting lens in meters

Beam 1: X = -0.135 m, Y = 0.0 m

Beam 2: X = 0.135 m, Y = 0.0 m

Beam 3: X = 0.0 m, Y = 0.135 m

Beam 4: X = 0.0 m, Y = -0.135 m

Transmission fraction of each of the four transmitted laser beams (power in each 

beam divided by the total input power for that component, e.g., input power is 

2.0 W for the horizontal component, output power in Beam 1 is 0.8 W →

0.8/2.0=0.4)

Beam 1: 0.356

Beam 2: 0.280

Beam 3: 0.356

Beam 4: 0.280

Polarization of each of the four transmitted beams in degrees: 0.0 is horizontal in 

degrees

Beam 1: 84 degrees

Beam 2: 89 degrees

Beam 3: 0 degrees

Beam 4: 0 degrees

Laser wavelength of each of the beam pairs that make up a velocity component 

in micro-meters

Beams 1 & 2: 0.5145 μm

Beams 3 & 4: 0.4880 μm

Input laser power for each of the beam pairs that make up a velocity component in 

Watts

Input to beams 1 & 2: 1.0 W

Input to beams 3 & 4: 1.0 W

Bragg frequency for each of the two velocity components in mega-Hertz

Beam 2: 40 MHz

Beam 4: 40 MHz

III.3

4

1 2

3
Receiver optics:

Focal distance of the receiving lens in meters

Focal distance: 4.36 m

Vertical (phi) and horizontal (theta) angles in degrees of the receiver lens with 

respect to the optical axis of the transmission optics centered at the 

measurement volume 

Phi: 0.0 degrees

Theta: 180.0 degrees

Effective lens diameter in meters: Diameter of receiver lens collecting light that 

passes through the spatial filter to the photomultipliers, e.g., a zoom lens is 

configured such that at a given focal length only the central 0.2 m diameter 

portion of the 0.3 m diameter lens collects light that passes through the 

spatial filter, thus the effective lens diameter is 0.2 m. 

Effective lens diameter: 0.3 m

Transmission fraction of the receiver optical system for each component (the 

scattered light power impinging on the photomultiplier divided by the 

collected scattered light power within the effective lens diameter, e.g., the 

power impinging the photomultiplier is 0.1 μW and the scattered light power 

collected within the effective lens diameter is 0.2 μW a transfer fraction of →

0.1/0.2=0.5) 

Horizontal component: 0.65

Vertical component: 0.65

Photomultiplier quantum efficiency as a fraction, e.g., a 21-percent quantum 

efficiency would be entered as 0.21

Quantum efficiency: 0.15

Photomultiplier gain in millions 

Gain: 1.0 M

Electronic gain in dB 

Electronic gain: 10 dB

The simulator applies the user characteristics of the transmission optical system and, 

assuming diffraction limited optics, determine the location and size of the measurement 

volumes. Optics corrected for chromatic aberrations and collimated laser beams are 

assumed so that the beam waist for all four laser beams is located at the common crossover point. The optical power distribution of each laser beam is assumed to be Gaussian 

along any diameter. The starting point for each particle will be in a vertical plane defined 

to extend to the 1/e3 power limits as defined by the laser power at the center of the 

measurement volume for the horizontal velocity component. This plane is located 

upstream from the measurement volume at the 1/e3 power point in the plane defined by 

the horizontal velocity component, i.e., beams 1 & 2. The particle is tracked through the 

measurement volume based on its original trajectory until it passes through the exit plane, 

the 1/e3 power point downstream of the measurement volume.

III.4
Now that the characteristics of the laser velocimeter optical system have been defined, the 

input flow field must be established. The flow field is assumed to have Gaussian 

distributions of velocity magnitude and the two flow angles alpha (vertical plane) and beta 

(horizontal plane). The user defines the desired flow field by inputting the mean and 

standard deviation of velocity magnitude in meters per second. Then the user defines the 

desired flow angles by inputting the means and standard deviations for the two flow angles 

in degrees. The velocity magnitude and the two flow angles are assumed to be independent 

variables, e.g., no cross coupling among the selection of the respective random numbers.

The user then inputs the index of refraction (real and imaginary) of the seeding particles 

and the desired particle size distribution from the following:

single size size in microns selected by the user 

Gaussian lower and upper standard deviation bounds selected by the user 

(Calculated inclusive to three standard deviation limits, 

e.g., 2 microns ±0.2 microns would be entered as 1.8 microns to 

2.2 microns and calculated from 1.4- to 2.6-microns)

uniform minimum and maximum sizes in microns selected by the user, 

and a uniform distribution in between

1/r3 (Junge (1955)) minimum and maximum sizes in microns selected by the user

(NOTE: The form of this distribution is automatically adjusted

to map the selected limits to the distribution limits set to 

0.4- to 1.0-microns (actual distribution in the atmosphere 

extends from 0.1- to 10.0-microns (Junge (1955))

The example particle size (0.1-micron resolution) is obtained from a random number 

generator configured to the characteristics of the selected particle size distribution. The 

velocity magnitude and two flow angles are obtained from their respective Gaussian 

random number generators. The starting point within the entrance plane is determined 

from two uniform random number generators that identify the vertical and on-axis 

locations respectively.

As the particle passes through the measurement volume along the randomly selected 

trajectory, an ideal signal based on Mie scattering theory as modified by Adrian and Earley 

(1975) is computed. The modified theory describes the scattering characteristics of a 

particle passing through two crossing coherent laser beams with a portion of the scattered 

light being collected within a given solid angle along a given direction. The theoretical 

amplitude of the collected light in watts is computed at spatial locations along the particle 

trajectory corresponding to a sample rate of 1.0 GHz until the particle passes through the 

exit plane. However, the scattered light amplitude is so low that it must be simulated as 

the arrival of single photons, (Mayo (1975)). This can be accomplished by integrating the 

III.5
sampled ideal signal to yield a plot of acquired light energy as a function of time. The first 

sample step of the integrated ideal signal represents the energy acquired during the first 

nanosecond that the particle was within the measurement volume. Knowing that photon 

arrivals obey Poisson statistics, a Poisson random number generator was used to generate 

the number of photon equivalent energies to match or exceed the ideal energy of the first 

step. The integrated energy of the first and second steps then sets the equivalent total 

photon energies needed for the Poisson random number generator to produce for the 

second step. This process continues at each step until the particle has left the 

measurement volume at the exit plane. The number of random counts needed to reach the 

integrated energy of the ideal waveform by the Poisson random number generator is the 

simulated number of integrated photon arrivals. Differentiating this integral yields the 

simulated signal burst generated by the particle as it passed through the measurement 

volume with a temporal resolution of 1.0 ns.

The approach used in the current simulation is a bit simpler and more direct. The 

amplitude of the ideal signal at each time step represents the “instantaneous” collected 

scattered optical power at that point. At a given step, the ideal amplitude establishes the 

average number of photons per second scattered by the particle at that point in time. 

Inverting this rate yields the mean time between photon arrivals. Using this mean time as 

the mean of the Poisson distribution governing the random number generator, photons are 

generated at this rate until the arrival time exceeds the ideal time for that step. The 

photon that was acquired beyond the ideal time becomes the first photon and arrival time 

for the next step. This approach increases the fidelity of the photon arrivals because the 

assumption that the “last” photon always increases the energy above the ideal level is not 

needed. Additionally, this model provides the temporal spacings of the photons within the 

step sample times, i.e., temporal resolutions less than 1.0 ns.

The resulting impulse train is then interrogated by the model of the photomultiplier 

quantum efficiency. Quantum efficiency is defined as the amount of light energy actually 

converted to photo-electrons within the photomultiplier. In an analog sense, 1.0 micro 

Joule of energy would be multiplied by the quantum efficiency, e.g., 15-percent, to yield the 

amount of energy, e.g., 0.15 micro Joules being converted to photo-electrons or current in 

the analog sense. A Monte Carlo simulation of this process would be a uniform random 

number generator yielding numbers from 0 to 1. An amplitude threshold would be 

established representing the quantum efficiency, e.g., 0.15, where random numbers less 

than or equal to 0.15 would allow the impulse to pass to the photomultiplier, and numbers 

greater than 0.15 would block that impulse. Thus for every impulse in the photon train a 

uniform random number is generated. If the random number allows passage, the impulse 

remains along with its arrival time, otherwise it is excluded. Each remaining impulse 

representing a single accepted photon is converted to a photo electron by replacing the 

impulse by the photomultiplier response function, assumed to be a triangle function with a 

2.5 ns rise time and a 2.5 ns fall time (Appendix A and Figure A.12). If there is any overlap 

among successive triangles, their amplitudes are added together to yield an analog, albeit 

noisy signal that has the characteristics of photon pile-up. This signal is then multiplied 

III.6
by the gain of the photomultiplier to yield the simulated signal exiting the photomultiplier. 

It is noted that electron gain is a Gaussian random process with the number of electrons 

multiplying at each dynode obeying Gaussian statistics. This is not simulated as this noise 

is far less that the noise imposed by the photon arrival process, and is thus considered 

negligible. Example signals from particles with velocities nominally 100 m/s passing 

through various trajectories at points along the optical axis in the plane of the horizontal 

component laser beams are shown in Appendix A, Figures A.13-A.19.

The final step in the signal generation process is to apply the characteristics of the system 

electronics and, if selected, down-mix the signal to lower the effective signal frequency. 

The TSI Fiberlight Laser Velocimeter contains circuitry that filters the pedestal from the 

signal burst. The simulator must perform this task with a high-pass filter whose value is 

user selected to match the Fiberlight system characteristics. The Fiberlight also allows the 

user to select a low-pass filter to reduce high frequency noise. This function is also 

included in the simulator with a user selected low-pass filter setting. If down-mixing is 

desired, the user selects the reference frequency to produce a signal matching the desired 

frequency difference using a model of a double-balanced mixer. The reference signal is a 

sine wave at the selected frequency which is mixed with the photon-resolved signal burst 

resulting in a burst containing the difference frequency being output from the mixer.

Now that an equivalent signal burst to that produced by the Fiberlight system has been 

simulated, a simulation of the data acquisition electronics can be performed. The input 

signal is digitized using a high-speed analog-to-digital converter (ADC) with the user 

defined sample rate that can be up to a maximum rate of 1.0 GHz. The ADC bit depth is 

set to 8-bits to match typical acquisition boards. If the ADC is used normally with 

triggering set to some fixed level, signal processing would be required to determine if the 

trigger setting was satisfactory to obtain signal bursts with good signal-to-noise ratios. 

This process was considered too time consuming for production testing. An alternative 

approach would employ a digital oscilloscope to monitor the signals in real time. In this 

way the researcher could adjust the trigger level until acceptable signals were viewed. As 

the oscilloscope generates an external trigger pulse each time a signal burst is acquired, 

this signal could be used to trigger the ADC to capture the same signal burst viewed on the 

oscilloscope.

Normally when viewing signal bursts of the type produced by a laser velocimeter, the 

threshold is set to a fairly low amplitude so that the majority of the signal burst may be 

inspected. This approach also allows signals with low signal levels and signal-to-noise 

ratios to trigger the scope near the middle of the burst. This has two disadvantages. First 

the noise contained in these low level signals will increase the measurement standard 

deviation and potentially affect the other statistical quantities. And secondly, the 

measurement volume is increased because the majority of the low signal levels are 

produced by particles passing through the edges of the measurement volume. The problem 

becomes even worse if poly-disperse particles are used for flow seeding. However the use of 

an ADC with pretriggering capabilities would allow one to trigger the oscilloscope at higher 

III.7
amplitudes thus viewing only signal bursts with good signal-to-noise ratios. Setting the 

pretrigger timing so that the circular storage registers on the ADC board would maintain 

the captured signal for a time that approximates half of the signal burst length to yield 

symmetric signal bursts. Applying the pretriggering capabilities available in the digital 

oscilloscope, the entire signal burst can be displayed even though triggering is set at 

amplitude levels near the center of the burst, which provides a display of the signals 

captured by the ADC. Thus only high signal-to-noise ratio signals generated by particles 

passing through the central portion of the measurement volume can be captured. 

Although the data rate would be reduced, the resulting measurements would be more 

accurate.

An additional benefit of viewing the signal bursts on the oscilloscope is that it also provides 

a measure of the signal amplitude. This feedback allows the input amplifier for the ADC to 

be adjusted to produce the desired amplitude resolution for the captured signals. A 

capture length of 10,000 samples would provide the processing software with the 

opportunity to interrogate the trace and optimize the selection of the portion to be Fourier 

transformed up to a length of 8192 samples. 

The data acquisition capability of the simulator models the operation described above. The 

1.0 GHz sampled floating point array containing the pedestal-removed signal burst 

generated by the model of the photomultiplier is filtered to simulate any in-line filters, and 

if selected, down-mixed to provide a signal for the model of the analog-to-digital converter. 

The signal burst is re-sampled at the user-selected rate and the amplitudes converted from 

floating point to an 8-bit integer array based on the user-selected ADC range. The integer 

array is then interrogated to determine if it triggers a burst capture based on the userselected trigger level. With center (high-level) triggering and pretrigger capabilities 

selected, a successful capture will store a 10,000 element array with half of the elements 

occurring before the trigger. 

Signal Processing

Now that the signal burst has been captured in the simulator or by the data acquisition 

hardware, signal processing can begin. The first step is to interrogate the signal trace and 

locate the peak voltage. This location is assumed to be at the center of the burst with the 

extent of the burst being defined at a cycle peak equal to 1/e2 times the peak voltage. A 

Bartlett (triangle) window is centered at the peak voltage location with its width set to the 

length of the burst. The remainder of the array containing the Bartlett window is set to 

the value of zero. Multiplying the captured signal trace by the Bartlett window will 

produce a symmetric signal burst without discontinuities. The resulting array is shifted to 

move the first non-zero value to the first array location and fast Fourier transformed with 

a length of the smallest power of 2 (from 7 (128 samples) to 13 (8,192 samples)) that would 

encompass the entire burst. 

III.8
The array containing the frequency domain representation of the signal burst is then 

transferred to the signal processing subroutine under investigation. Frequency domain 

processing was selected because higher measurement accuracies can be obtained with less 

computational resources than equivalent time-domain approaches. The following six 

frequency domain processing schemes were written, verified and evaluated:

Peak Location The highest peak is found and its frequency value returned

Gaussian Fit A Gaussian fit is applied to the highest peak ±1 frequency step – 

the calculated frequency at the peak of the fit is returned

Histogram Fit (3) The highest peak, ±1 frequency step, is processed as if it was a 

histogram where the weighted average frequency is returned

Histogram Fit (5) The highest peak, ±2 frequency steps, is processed as if it was a 

histogram where the weighted average frequency is returned

Half Power The amplitude of the highest peak is used to determine the 

frequency steps that lie within the half power limits – weighted 

average frequency is returned

True Half Power Same as Half Power except the true locations of the half power 

points are determined using linear interpolation to find the 

weights and frequencies at the half power points – weighted 

average frequency is returned.

Example Particles 

The primary advantage of the Monte Carlo simulation approach to investigate the 

characteristics of the system being designed is the ability to track a single particle and its 

resultant signal through the entire optical, electronic, and processing path. This can be 

easily followed by selecting example parameters that represent the upgraded laser 

velocimeter and sending a particle through the measurement volume at a random 

trajectory to generate a signal burst. This signal burst can then be processed to yield the 

measured component velocities from each of the six processing schemes and determine the 

exact error from each method. Although all of the random number generators will be used 

in this example, seven example particle trajectories will be selected that pass through the 

vertical center of the measurement volume at the 1/e, 1/e2, and 1/e3 locations along the 

optical axis. The particles selected are 1.7-micron diameter PSL particles thus matching 

those currently used in the 14-by 22-Foot Subsonic Tunnel. The resultant signals, Figures 

A.13-A.19 in Appendix A, illustrate the variations in signal characteristics based on 

particle trajectory, and the morphing of the signal from theory, to the Poisson statistics of 

the photomultiplier output, to the effects of pedestal removal and digitizing by the ADC.

III.9
The example laser velocimeter parameters are set to match the upgraded laser velocimeter 

with a focal distance to place the measurement volume at the tunnel centerline:

Transmission optics:

4.877 Focal distance of the transmitting lens, m

0.0175 Diameter of the laser beam at the focusing lens, m

-0.1294, 0.0 U-component, Beam 1 Location (X, Y), m

0.1294, 0.0 U-component, Beam 2 Location (X, Y), m

0.0, -0.1294 V-component, Beam 1 Location (X, Y), m

0.0, 0.1294 V-component, Beam 2 Location (X, Y), m

0.31 U-component, Beam 1 transmission fraction

0.28 U-component, Beam 2 transmission fraction

0.31 V-component, Beam 1 transmission fraction

0.28 V-component, Beam 2 transmission fraction

84.0 U-component, Beam 1 polarization, degrees (90 = vertical)

89.0 U-component, Beam 2 polarization, degrees (90 = vertical)

0.0 V-component, Beam 1 polarization, degrees

0.0 V-component, Beam 2 polarization, degrees

0.5145 U-component wavelength, microns

0.4880 V-component wavelength, microns

1.0 U-component power, W

1.0 V-component power, W

40.0 U-component Bragg frequency, MHz

40.0 V-component Bragg frequency, MHz

Receiver optics:

4.877 Focal distance of the receiving lens, m

0.0 Vertical (phi) angle of the receiver lens, degrees

180.0 Horizontal (theta) angle of the receiver lens, degrees

0.275 Effective receiving lens diameter, m

0.65 U-component transmission factor

0.65 V-component transmission factor

0.15 Photomultiplier quantum efficiency, fraction

1.0 Photomultiplier gain, M

10.0 Electronic gain, dB

2.0 U-component high-pass filter, MHz

2.0 V-component high-pass filter, MHz

100.0 U-component low-pass filter, MHz

100.0 V-component low-pass filter, MHz

Particle characteristics:

1.59, 0.0 Index of refraction, real, imaginary

1.7 Particle size

III.10
Flow characteristics:

100.0, 3.0 Mean velocity magnitude, standard deviation, m/s

0.0,4.0 Mean vertical flow angle, standard deviation, degrees

0.0,0.0 Mean horizontal flow angle, standard deviation, degrees

ADC characteristics:

0.05 Triggering threshold, V

1.0 ±Full-scale ADC voltage, V

1000.0 Sample rate, MHz

The comparison of the six signal processing techniques applied to the seven example 

particle trajectories provides insight into the capabilities of the techniques, Table III.1. 

The two histogram techniques provided measurements from all of the particles whereas 

the remaining techniques only yielded five measurements each, all from the vertical center 

of the measurement volume. The True Half Power scheme yielded the greatest accuracy 

for the U-component measurement (0.04 m/s ±0.14 m/s), whereas the Histogram (5) 

scheme yielded the greatest accuracy for the V-component measurement (0.06 m/s 

±0.12 m/s). The worst case among these two processing schemes was 0.15 m/s ±0.21 m/s, 

well within the required specifications.

Statistical Comparisons

In order to determine how the performance of True Half Power and Histogram (5) 

processing schemes would translate to the real world, a wind tunnel test simulation was 

conducted. An ensemble of 10,000 particles was launched through the entrance plane in 

the simulator based on a mean velocity magnitude of 100.0 m/s with a standard deviation 

of 3.0 m/s, and a vertical flow angle of 0.0 degrees with a standard deviation of 4.0 degrees. 

Histograms of particle position at the entrance plane, Figure III.2, indicate that the 

particles were uniformly distributed within the plane except at the extents of the 

measurement volume. The vertical distributions in the exit plane show the effects of the 

4.0-degree standard deviation in flow angle. The statistics of the injection position 

ensembles are compared with the requested characteristics in Table III.2. The statistics of 

the randomly selected particle velocity magnitude and flow angle are also in Table III.2 and 

have an average velocity magnitude of 99.98 m/s with a standard deviation of 2.96 m/s, 

versus 100.0 m/s and 3.0 m/s requested. The vertical flow angle was found to have a mean 

of 0.01 degrees with a standard deviation of 4.02 degrees, versus 0.0 degrees and 

4.0 degrees requested. This produced a U-component mean of 99.74 m/s with a standard 

deviation of 2.98 m/s, and a V-component mean of 0.02 m/s with a standard deviation of 

7.0 m/s. Of the 9382 particles that triggered data capture, the U-component mean was 

99.72 m/s with a standard deviation of 2.98 m/s, and a V-component mean of -0.01 m/s with 

a standard deviation of 6.97. The distributions of velocity and flow angle are shown in 

Figure III.3 for the randomly selected particles, and in Figure III.4 for the triggering 

particles. The statistics and distributions indicate that the simulator matched the desired 

particle characteristics with good fidelity. And as expected, with the relatively small 

III.11
standard deviations in velocity magnitude and flow angle, the distributions for the U- and 

V-components were nearly Gaussian.

The ability of the simulator to record the actual velocity and trajectory for each particle 

along with the measured results provides the information needed to separate measurement 

precision from measurement accuracy. For example, from Table III.3 the effects of 

reducing the number of potential measurements to only those with signal levels sufficient 

to trigger the oscilloscope (9382 bursts) are found by a slight decrease in measurement 

accuracy and a relatively small change in their distributions, Figure III.4. The trend of 

reduced accuracy continues when the signal processing technique excludes signal bursts 

that have insufficient signal-to-noise ratios or other exclusions inherent with the 

processing technique. For example from Table III.3, the Peak processing technique 

reduces the accepted number of signal bursts to 6040.

From experience it is known that laser velocimeter signal processors of any type will allow 

spurious measurements to be made. This was particularly true with the high-speed burst 

counters developed in the 1970s. In the late 1980's researchers began to investigate causes 

of measurement uncertainty in laser velocimetry measurements and to develop methods to 

correct or eliminate those uncertainties (Edwards (1987)). The common practice of 

eliminating measurements that were found to be outside the limits of three standard 

deviations of the measurement ensemble was found to be ineffective. This was due to the 

nature of the spurious measurements in that they could occur far from the actual 

distribution. The inclusion of these outliers in the calculation of standard deviation would 

artificially increase its value, even to the point of including outliers within the allowed 

three standard deviation window. Meyers and Hepner (1988) reasoned that these spurious 

measurements were randomly distributed and typically well away from the true velocity 

measurements. Thus instead of assuming that the velocity distribution was Gaussian in 

form and thus followed Gaussian statistics, they developed a method to determine the 

limits of the distribution regardless of its form or underlying statistics. They reasoned that 

if the measurement ensemble contained sufficient data points, the velocity histogram of 

the ensemble would be contiguous until the limits were reached. The limits were 

determined by developing an amplitude threshold based on 5-percent of the value of the 

peak histogram bin, or the value of 3 whichever is larger. This level would correspond to 

the amplitude of a Gaussian distribution at the three standard deviation location. The 

envelope of the histogram would be followed from the peak toward the right (higher 

velocities) until the envelope went below the threshold for three consecutive bins. The 

limit of the histogram was then located at the last bin before the envelope went below the 

threshold. All data to the right of this location was considered spurious and eliminated 

along with corresponding data obtained from the other measurement components if the 

data was acquired in coincidence. As each spurious datum was removed from the 

component ensemble, the neighboring interarrival times were adjusted to maintain the 

integrity of measurement time. The process was then repeated on the left side of the 

histogram. This method has been incorporated in the current data processing schemes. 

Application of this technique to the results from the Peak processing technique, reduced 

III.12
the number of acceptable signals to 4264. Although the errors, (mean and standard 

deviation of the velocity differences based on measured versus actual particle velocity on 

particle-by-particle computations and thus measurement precision), shown in Table III.3 

have increased, they are still within the acceptable range. However, when the histograms 

are inspected, Figure III.5, one finds that the distribution of particle velocity has deviated 

from a Gaussian form (overlay), especially in the V-component. These distributions are 

further distorted by the Peak processing technique, resulting in measurements that should 

be considered unacceptable.

Replacing the Peak processing technique with the other techniques produced 

measurements of increased accuracy in both the statistics and in the distributions. The 

Gaussian processing technique accepted the same number of signal bursts as the Peak 

processing technique, but had fewer outliers, Table III.3. The increased number of 

accepted bursts (5909) improved the fidelity of the particle velocity histograms when 

compared to the theoretical Gaussian distributions. The measurement statistics and 

histograms also improved, but not to the point of acceptability, Figure III.6. The two 

Histogram processing techniques improved measurement fidelity in two ways, increased 

number of accepted signal bursts (7633) and distributions that closely matched the 

theoretical Gaussian distributions. Although the Histogram (3) approach yielded slightly 

better precision, Table III.3, the Histogram (5) approach produced far better distributions 

and thus should be considered the superior method, Figures III.7-III.8. Finally the two 

Half Power processing techniques also yielded acceptable measurement errors and nearly 

matching the theoretical Gaussian distributions, Figures III.9-III.10, but only 6040 signal 

bursts were accepted which may be the cause of the decrease in fidelity in the 

distributions. All techniques required approximately the same amount of time to process 

the data ensemble, thus there is no clear advantage of one over the rest. It is also noted 

that in this simulation investigation neither the Histogram or Half Power methods had 

outliers. Therefore, based on the simulation results, it appears that the Histogram (5) 

method is the superior approach based on measurement precision and the fidelity of the 

measured histograms when compared with the particle velocity histograms.

The characteristics of the six signal processing schemes found in the velocity magnitude 

and flow angle measurements continued with the U- and V-component measurements, 

Table III.3 and Figures III.11-III.16. Therefore the selected signal processing scheme was 

the Histogram (5) approach, which was then incorporated into the data processing 

software for the final system. A summary of all ensemble characteristics is given in 

Table III.2.

Analyzing the Statistical Results

The previous section indicated that the Histogram (5) approach yielded the best 

measurement accuracy of the six techniques. Yet one of the contributors to its superior 

performance was the larger number of signal bursts accepted, leading to better fidelity of 

the statistical stationarity of the particle velocity and, because of its better measurement 

III.13
precision, increased measurement accuracy of the velocity distributions. Thus the 

measurement accuracy was improved and found superior to the other techniques. 

However, if the characteristics of the original distribution are unknown, e.g, flow field 

measurements in a wind tunnel, there is no current method to determine when the 

measurement distribution actually reflects the true distribution with acceptable fidelity. 

From classic statistical analysis it is known that the uncertainty in the measure of the 

ensemble mean and its standard deviation is dependent on the number of measurements in 

the ensemble (Yule and Kendall (1940)):

(3)

(4)

where σ is the ensemble standard deviation, N is the number of independent data points 

in the ensemble and E is the statistical excess (kurtosis -3) of the ensemble. Excess 

provides an adjustment to the uncertainty in standard deviation to account for nonGaussian distributions. Since the characteristics of the “flow field” are known with the 

simulation, the statistical uncertainties can be computed for a series of partial ensembles 

derived from the original measurement ensembles. For example, the mean and standard 

deviation would be calculated along with their respective measurement uncertainties for 

the first 100 measurements. Then the next 100 measurements are included in the first 

ensemble and the statistics calculated again. The process would continue until the entire 

measurement ensemble was included. This was performed on the measurement ensembles 

obtained from the six data processing schemes. The calculations of the statistical mean 

velocity magnitude as a function of ensemble size are shown in Figure III.17. The results 

from the Peak processing technique never reach the true mean of the velocity magnitude, 

which reinforces the earlier conclusion that this technique was unacceptable. While the 

Gaussian processing technique stabilizes at approximately 2000 measurements and the 

true mean is within the statistical uncertainty region, it is still marginally acceptable 

because of the poor representation of the velocity distribution. The two Histogram 

processing techniques stabilize at approximately 700 measurements with a small positive 

velocity bias. The two Half Power processing techniques stabilize at approximately 2000 

measurements, also with a small positive velocity bias. Tracking the standard deviation 

measurements in Figure III.18 indicate similar trends, an underestimation with Peak 

processing, marginal underestimation with the Gaussian processing and virtually no error 

with the other methods. Tracking the skew measurements in Figure III.19 indicate 

marginally better performance by the Histogram methods over the Half Power methods 

with the Peak and Gaussian unacceptable. The results for excess, Figure III.20, indicate 

that the Half Power method was virtually perfect, the True Half Power and Histogram 

methods slightly worse and the Peak and Gaussian methods unacceptable. These trends 

continued with the flow angle (Figures III.21-III.24), U-component velocity (Figures III.25-

III.28), and V-component velocity (Figures III.29-III.32). 

III.14

Uncertainty in the mean = 2σ

√ N

Uncertainty in standard deviation = σ √

2

N (

1+

E

2 )
This exercise has shown that tracking the measurement statistics as a function of 

ensemble size yields an asymptotic approach to the true statistics of the flow field. This 

may provide an indicator during the acquisition process that could be used in a feedback 

sense to determine when sufficient data points have been acquired. Since it was found in 

the previous section that histograms of the measurement distributions did not necessarily 

match the particle velocity histograms even though the means and standard deviations 

were fairly accurate, is tracking the means and standard deviations as a function of 

ensemble size sufficient to predict measurement fidelity? Although the statistical 

measures of skew and excess (kurtosis – 3) require larger ensembles than the means and 

standard deviations, they do converge to the true values for the Histogram and Half-Power 

methods, Figures III.19 and III.20. They also track the skew and excess statistics from the 

true particle velocity ensembles with good fidelity. 

The overlay of the measurement statistics on the particle statistics appears to show that 

measurement precision is independent of measurement accuracy. To test whether this is 

true, the errors between the particle velocity/flow angle and the measured velocity/flow 

angle were computed on a particle-by-particle basis and the resulting error ensembles 

processed in the same manner as the convergence tests above. As shown in Figures III.33-

III.36, the convergence of the error statistics occurs in the neighborhood of 500 particles. 

This indicates that sparse data sets within narrow error distributions is the cause of any 

convergence, not a dependency on the processing. As a comparison, these errors were well 

within the statistical uncertainties of the velocity/flow angle measurements.

In summary, a Monte Carlo simulator was used to model the upgraded 14-by 22-Foot 

Subsonic Tunnel laser velocimeter system. The simulator produced signal bursts from a 

simulated flow with a mean velocity magnitude of 100.0 m/s with a standard deviation of 

3.0 m/s, and a mean vertical flow angle of 0.0 degrees with a standard deviation of 

4.0 degrees. The horizontal flow angle was held at 0.0 degrees with no standard deviation 

as the laser velocimeter was incapable of measuring the on-axis component, and the 

inclusion of this angle could potentially modify the velocity distributions in the U- and Vcomponents from being nominally Gaussian. The particles were injected within a plane 

defined by the 1/e3 power locations in the on-axis and vertical directions based on the 

optical power at the center of the measurement volume. This plane was located upstream 

at the 1/e3 power location. The simulator generated 10,000 1.7-micron PSL particles that 

entered this injection plane in a random manner with uniform statistics, Figure III.2, 

following the selected velocity magnitude and flow angle characteristics to generate 

random velocity magnitudes and flow angles with Gaussian statistics. The selection of 

velocity and flow angle was independent for each particle, thus no cross-dependence 

occurred between the two parameters. Of the 10,000 particles generated, 9382 passed 

through the measurement volume with sufficient signal strength to trigger the data 

acquisition system. Of these 9382 triggered signal bursts, only between 4264 to 7633 were 

processed depending on the signal/data processing scheme applied. 

III.15
All six signal/data processing schemes under investigation processed the signal bursts in 

the frequency domain. The simplest was to detect the highest peak in the frequency 

spectra and output its location. This method processed the fewest signal bursts, with the 

worst measurement precision and measurement accuracy of the six schemes. The 

Gaussian approach detected the highest peak in the frequency spectra and curve fit the 

peak level ±1 frequency step with a Gaussian fit and then determined the location of the 

peak of the curve. This method was an improvement on the Peak method, but only 

slightly. Two Histogram approaches were evaluated with the highest peak location in the 

frequency spectra being the central element of a 3-bin and a 5-bin histogram. The signal 

frequency was determined by the weighted statistics of the histogram. These methods 

accepted the greatest number of signal bursts and thus, along with excellent measurement 

precision, yielded good measurement accuracy. The 5-bin method produced the best 

fidelity of any method when the measurement velocity histograms were compared to the 

particle velocity histograms. The final two approaches were similar to the histogram 

approaches in that the frequency spectra was processed as a histogram. The difference was 

that only bins yielding counts within the half-power of the peak level were included. One 

method used just the bins with levels greater than the half-power value, whereas the other 

interpolated the bin levels to obtain the exact locations of the half-power points, thus 

extending the width of the histogram by fractions of a bin. These methods accepted fewer 

signal bursts than the histogram methods, but measurement precision was the best except 

the velocity distributions did not have the fidelity of the Histogram (5) method. All 

methods showed strong convergence trends to their final values as the ensemble size was 

increased providing a method to determine when measurement and flow statistical 

stationarity was reached. Of the statistical quantities examined, standard deviation 

appears to provide the least deviation from the true particle velocity characteristics yet 

maintained the most stable convergence to the true value.

The following conclusions can be drawn from this simulation:

1) Measurement precision and measurement accuracy could be determined 

independently;

2) Measurement precision was virtually constant regardless of ensemble size;

3) Measurement accuracy depends on ensemble size with an asymptotic approach to 

the true value;

4) The measurement statistics track the particle statistics through the ensemble 

size range;

5) The true velocity/flow angle means and standard deviations fall within the 

statistical uncertainty calculations of mean and standard deviation of the 

particle and measurement ensembles;

6) Peak and Gaussian signal processing schemes are unacceptable;

7) The two Histogram methods and the Half-Power methods yield acceptable 

statistical results;

8) The two Histogram methods accept the greatest number of signal bursts;

9) The Histogram (5) method best replicates the true distributions and thus is 

III.16
selected as the prime signal/data processing method even though its statistical 

results were slightly less accurate than the Half-Power methods; 

 10) Measurement accuracy can be defined in different ways. If the true mean velocity 

magnitude and flow angle was 100.0 m/s and 0.0 degrees, respectively, the errors 

in the corresponding means were 0.07 m/s and 0.01 degrees for both the 

Histogram (5) and True Half Power methods. The true standard deviations were 

3.0 m/s and 4.0 degrees with measurement errors of 0.01 m/s and 0.03 degrees for 

the Histogram (5) method and 0.04 m/s and 0.05 degrees for the True Half Power 

method. However, the true mean velocity and flow angle for the particle 

ensemble that was actually measured was 99.95 m/s and -0.03 degrees with 

standard deviations of 2.97 m/s and 4.03 degrees for the Histogram (5) set and 

2.96 m/s and 4.05 degrees for the True Half Power set. In this case both the 

Histogram (5) and True Half Power methods would have errors in the mean of 

0.12 m/s and 0.04 degrees with the only error in standard deviation being 

0.02 m/s by the Histogram (5) method. 

 11) On a particle-by-particle basis, both the Histogram (5) and True Half Power 

methods have an error in the mean of 0.12 m/s and 0.05 degrees which match the 

measurement accuracies for the ensembles of signal bursts actually measured. 

The standard deviation of the particle-by-particle errors are much larger than the 

accuracy results, 0.40 m/s and 0.23 degrees for the Histogram (5) method and 

0.28 m/s and 0.14 degrees for the True Half Power.

 12) It appears that the instrument precision in the means account for all of the 

errors in the mean measurements when considering the ensemble of signal 

bursts actually measured. It also appears that the standard deviation portion of 

the instrument precision must average out and makes no contribution to 

measurement error in standard deviation. 

 13) The above statistical results were obtained once the standard deviation had 

converged to the statistically stationary value.

Therefore, based on the results from the Monte Carlo simulation, the required 

measurement accuracy of ±1.5 m/s can be theoretically satisfied. Additionally, a method to 

track measurement statistics as a function of ensemble size is necessary to insure that the 

flow measurements faithfully represent the characteristics of the actual flow field before 

termination of data acquisition at a selected measurement location. Otherwise no matter 

how precise the laser velocimetry measurements were, there can be no assurance that the 

flow measurements would be accurate. Even after convergence, there would still be no 

guarantee that the signal bursts being processed will accurately represent the true flow 

with statistical stationarity.

III.17
Table III.1.a.- Laser velocimeter Monte Carlo simulation results – Single particle passage.

III.18

Beam Waist 182.6 microns (Meyers (1971))

Sample Volume Length 4.868 mm

Particle Vertical distance On axis distance Particle Vectors

Y/Beam Waist Radius 2*Z/Sample volume length Vel-mag Alpha Beta

Start End Start End (m/s) (degrees) (degrees)

1 0.011 0.342 -1.483 -1.483 103.29 6.31 0.00

2 0.012 0.392 -1.006 -1.006 99.18 7.22 0.00

3 0.02 -0.319 -0.503 -0.503 100.57 -6.44 0.00

4 -0.009 0.266 -0.006 -0.006 105.32 5.23 0.00

5 0.01 -0.156 0.491 0.491 98.05 -3.18 0.00

6 0.022 -0.055 0.994 0.994 100.05 -1.46 0.00

7 0.009 0.161 1.499 1.499 97.46 2.9 0.00

U-Component (m/s)

Actual Peak Location Gaussian Fit Histogram (3) Histogram (5) Half Power Half Power True

1 102.666 102.27 102.8

2 98.398 97.58 97.93 98.26 98.47 98.69 98.65

3 99.936 99.95 99.97 100.01 100.25 99.98 99.99

4 104.885 104.68 104.77 104.93 104.99 104.87 104.87

5 97.896 97.58 97.67 97.79 97.79 97.76 97.76

6 100.02 99.95 100.01 100.12 100.54 100.04 100.07

7 97.337 97.32 97.34

U-Component Error (m/s)

1 -0.4 0.14

2 -0.82 -0.47 -0.14 0.07 0.29 0.25

3 0.01 0.03 0.07 0.32 0.04 0.05

4 -0.2 -0.12 0.04 0.11 -0.01 -0.01

5 -0.32 -0.22 -0.1 -0.11 -0.13 -0.13

6 -0.07 -0.01 0.1 0.52 0.02 0.05

7 -0.02 0.01

Average: -0.28 -0.16 -0.06 0.15 0.04 0.04

Sigma: 0.33 0.20 0.17 0.21 0.15 0.14

V-Component (m/s)

Actual Peak Location Gaussian Fit Histogram (3) Histogram (5) Half Power Half Power True

1 11.358 11.49 11.36

2 12.462 11.68 11.93 12.33 12.62 12.72 12.69

3 -11.279 -10.78 -10.9 -11.09 -11.35 -10.98 -11.03

4 9.601 9.44 9.49 9.58 9.58 9.55 9.55

5 -5.437 -6.29 -6.06 -5.64 -5.31 -5.24 -5.24

6 -2.555 -1.8 -2.01 -2.31 -2.58 -2.79 -2.73

7 4.931 5.15 5.18

V-Component Error (m/s)

1 0.13 0 

2 -0.78 -0.53 -0.13 0.16 0.26 0.22

3 0.5 0.38 0.19 -0.07 0.3 0.25

4 -0.17 -0.11 -0.02 -0.02 -0.05 -0.05

5 -0.85 -0.63 -0.2 0.13 0.19 0.19

6 0.76 0.55 0.24 -0.02 -0.23 -0.18

7 0.21 0.25 

Average: -0.11 -0.07 0.06 0.06 0.09 0.09

Sigma: 0.73 0.53 0.18 0.12 0.23 0.19
Table III.1.b.- Calculated results for the selected particles based on six signal processing algorithms 

based on FFT processing.

III.19

Particle Vertical distance On axis distance U-component V-component

Y/Beam Waist Radius 2*Z/Sample volume length Actual Measured Error Actual Measured Error

Start End Start End m/s m/s m/s m/s m/s m/s

Peak Location

1 0.011 0.342 -1.483 -1.483 102.666 11.358

2 0.012 0.392 -1.006 -1.006 98.398 97.58 -0.82 12.462 11.68 -0.78

3 0.02 -0.319 -0.503 -0.503 99.936 99.95 0.01 -11.279 -10.78 0.5

4 -0.009 0.266 -0.006 -0.006 104.885 104.68 -0.2 9.601 9.44 -0.17

5 0.01 -0.156 0.491 0.491 97.896 97.58 -0.32 -5.437 -6.29 -0.85

6 0.022 -0.055 0.994 0.994 100.02 99.95 -0.07 -2.555 -1.8 0.76

7 0.009 0.161 1.499 1.499 97.337 4.931

Gaussian Fit

1 0.011 0.342 -1.483 -1.483 102.666 11.358

2 0.012 0.392 -1.006 -1.006 98.398 97.93 -0.47 12.462 11.93 -0.53

3 0.02 -0.319 -0.503 -0.503 99.936 99.97 0.03 -11.279 -10.9 0.38

4 -0.009 0.266 -0.006 -0.006 104.885 104.77 -0.12 9.601 9.49 -0.11

5 0.01 -0.156 0.491 0.491 97.896 97.67 -0.22 -5.437 -6.06 -0.63

6 0.022 -0.055 0.994 0.994 100.02 100.01 -0.01 -2.555 -2.01 0.55

7 0.009 0.161 1.499 1.499 97.337 4.931

Histogram (3)

1 0.011 0.342 -1.483 -1.483 102.666 102.27 -0.4 11.358 11.49 0.13

2 0.012 0.392 -1.006 -1.006 98.398 98.26 -0.14 12.462 12.33 -0.13

3 0.02 -0.319 -0.503 -0.503 99.936 100.01 0.07 -11.279 -11.09 0.19

4 -0.009 0.266 -0.006 -0.006 104.885 104.93 0.04 9.601 9.58 -0.02

5 0.01 -0.156 0.491 0.491 97.896 97.79 -0.1 -5.437 -5.64 -0.2

6 0.022 -0.055 0.994 0.994 100.02 100.12 0.1 -2.555 -2.31 0.24

7 0.009 0.161 1.499 1.499 97.337 97.32 -0.02 4.931 5.15 0.21

Histogram (5)

1 0.011 0.342 -1.483 -1.483 102.666 102.8 0.14 11.358 11.36 0

2 0.012 0.392 -1.006 -1.006 98.398 98.47 0.07 12.462 12.62 0.16

3 0.02 -0.319 -0.503 -0.503 99.936 100.25 0.32 -11.279 -11.35 -0.07

4 -0.009 0.266 -0.006 -0.006 104.885 104.99 0.11 9.601 9.58 -0.02

5 0.01 -0.156 0.491 0.491 97.896 97.79 -0.11 -5.437 -5.31 0.13

6 0.022 -0.055 0.994 0.994 100.02 100.54 0.52 -2.555 -2.58 -0.02

7 0.009 0.161 1.499 1.499 97.337 97.34 0.01 4.931 5.18 0.25

Half Power

1 0.011 0.342 -1.483 -1.483 102.666 11.358

2 0.012 0.392 -1.006 -1.006 98.398 98.69 0.29 12.462 12.72 0.26

3 0.02 -0.319 -0.503 -0.503 99.936 99.98 0.04 -11.279 -10.98 0.3

4 -0.009 0.266 -0.006 -0.006 104.885 104.87 -0.01 9.601 9.55 -0.05

5 0.01 -0.156 0.491 0.491 97.896 97.76 -0.13 -5.437 -5.24 0.19

6 0.022 -0.055 0.994 0.994 100.02 100.04 0.02 -2.555 -2.79 -0.23

7 0.009 0.161 1.499 1.499 97.337 4.931

Half Power True

1 0.011 0.342 -1.483 -1.483 102.666 11.358

2 0.012 0.392 -1.006 -1.006 98.398 98.65 12.69 12.462 0.25 0.22

3 0.02 -0.319 -0.503 -0.503 99.936 99.99 -11.03 -11.279 0.05 0.25

4 -0.009 0.266 -0.006 -0.006 104.885 104.87 9.55 9.601 -0.01 -0.05

5 0.01 -0.156 0.491 0.491 97.896 97.76 -5.24 -5.437 -0.13 0.19

6 0.022 -0.055 0.994 0.994 100.02 100.07 -2.73 -2.555 0.05 -0.18

7 0.009 0.161 1.499 1.499 97.337 4.931
Table III.2.a.- Laser Velocimeter Results: Theory, Simulated, Selected and Signal Processing – Peak and 

Gaussian.

III.20

P article Injection L ocatio n

Theo ret ical Simulat ion

Y-st art Z-st art Y-st art Z-st art Y-en d Z -end

(*1/e^2) (*1/e^2) (*1/e^2) ( *1/e^2) (*1/e^2) (*1/e^2)

Numb er 10000 10000 10000 10000

M axim um 1.50 1.50 1.50 1.50 2.04 1.50M inimu m -1.50 -1.50 -1.50 -1.50 -2.11 -1.50M ean 0.00 0.00 0.01 0.00 0.01 0.00

0.91 0.91 0.87 0.87 0.89 0.87

Skew 0.00 0.00 -0.03 0.01 -0.01 0.01Excess -1.20 -1.20 -1.21 -1.19 -1.07 -1.19

Select ed fro m Ideal Dist rib utio n Trigg ered

Alph a U -in V- in U-select V-select

( m/s) (deg ree) (m/s) (m/s) ( m/s) (m/s)

Numb er 10000 10000 10000 10000 9382 9382

M axim um 110.31 15.97 110.10 27.32 110.10 27.32M inimu m 89.23 -15.34 88.86 -26.45 88.86 -26.45M ean 99.98 0.01 99.74 0.02 99.72 -0.01

2.96 4.02 2.98 7.00 2.98 6.97

Skew -0.03 0.00 -0.03 0.00 -0.02 0.00Excess 0.00 -0.01 -0.01 -0.02 -0.02 -0.01? Mean 0.06 0.08 0.06 0.14 0.06 0.14

0.04 0.06 0.04 0.10 0.04 0.10

(S ig nal bu rsts have trigg ered the o scilloscop e, sat isfied sig nal-t o-n oise th resh olds for th e processing alg orith m, and out liers remo ved)

Peak Sig nal P ro cessin g Algo rithm

Alph a Mag-m eas Alph a- meas Error-Mag E rror-Alp ha U-select V-select U-m eas V-meas Error U Erro r V

( m/s) (deg ree) (m/s) (deg ree) ( m/s) (deg ree) ( m/s) (m/s) ( m/s) (m/s) ( m/s) (m/s)

Numb er 4264 4264 4264 4264 4264 4264 4264 4264 4264 4264 4264 4264

M axim um 106.03 3.59 105.03 3.05 1.92 0.93 105.95 6.13 104.68 4.94 1.93 1.55M inimu m 89.95 -5.83 90.48 -5.39 -1.78 -0.73 89.83 -9.97 90.47 -8.54 -1.75 -1.29M ean 99.73 -0.69 99.83 -0.65 0.09 0.04 99.64 -1.19 99.73 -1.12 0.09 0.07

2.76 2.42 2.83 2.41 0.70 0.38 2.77 4.21 2.83 4.19 0.70 0.66

Skew -0.21 -0.19 -0.23 -0.20 0.05 0.03 -0.21 -0.19 -0.23 -0.19 0.05 0.03Excess -0.21 -1.02 -0.28 -1.06 -1.08 -1.14 -0.22 -1.03 -0.29 -1.07 -1.09 -1.15? Mean 0.08 0.07 0.09 0.07 0.02 0.01 0.08 0.13 0.09 0.13 0.02 0.02

0.06 0.04 0.06 0.04 0.01 0.01 0.06 0.06 0.06 0.06 0.01 0.01

Gau ssian Signal Processing A lgorith m

Alph a Mag-m eas Alph a- meas Error-Mag E rror-Alp ha U-select V-select U-m eas V-meas Error U Erro r V

( m/s) (deg ree) (m/s) (deg ree) ( m/s) (deg ree) ( m/s) (m/s) ( m/s) (m/s) ( m/s) (m/s)

Numb er 5909 5909 5909 5909 5909 5909 5909 5909 5909 5909 5909 5909

M axim um 108.21 8.91 108.08 8.76 1.61 0.77 108.12 15.19 107.31 14.23 1.70 1.33M inimu m 89.23 -11.93 88.64 -11.77 -1.42 -0.62 88.86 -20.88 88.35 -20.06 -1.39 -1.08M ean 99.90 -0.18 100.01 -0.13 0.11 0.04 99.68 -0.31 99.78 -0.23 0.11 0.08

2.91 3.83 2.96 3.83 0.51 0.28 2.93 6.66 2.97 6.67 0.51 0.48

Skew -0.07 -0.17 -0.07 -0.18 0.04 0.02 -0.07 -0.17 -0.07 -0.18 0.04 0.01Excess -0.07 -0.34 -0.09 -0.34 -0.97 -1.07 -0.08 -0.35 -0.08 -0.35 -0.97 -1.08? Mean 0.08 0.10 0.08 0.10 0.01 0.01 0.08 0.17 0.08 0.17 0.01 0.01

0.05 0.06 0.05 0.06 0.01 0.00 0.05 0.11 0.05 0.11 0.01 0.01

St andard D ev

Vel- mag

St andard D ev

? Stand ard Dev

Vel- mag

St andard D ev

? Stand ard Dev

Vel- mag

St andard D ev

? Stand ard Dev
Table III.2.a. (cont'd) - Laser Velocimeter Results: Signal Processing – Histogram (3), Histogram (5), Half 

Power, and True Half Power.

III.21

Hist ogram ( 3) Sign al P rocessing Algorithm

Alph a Mag-m eas Alph a- meas Error-M ag Error-Alp ha U-select V -select U-m eas V-meas Error U Erro r V

( m/s) (deg ree) (m/s) (deg ree) (m/s) (deg ree) (m/s) (m/s) (m/s) (m/s) (m/s) (m /s)

Numb er 7633 7633 7633 7633 7633 7633 7633 7633 7633 7633 7633 7633

M axim um 110.31 13.96 110.59 14.06 1.85 1.02 110.10 25.12 109.89 25.20 1.85 1.71M inimu m 89.23 -15.34 88.96 -15.20 -1.53 -1.14 88.86 -26.45 88.40 -26.36 -1.56 -1.97M ean 99.95 -0.03 100.06 0.01 0.11 0.05 99.70 -0.06 99.81 0.02 0.11 0.08

2.97 4.03 2.98 4.03 0.31 0.18 2.98 7.01 3.00 7.02 0.31 0.31

Skew -0.01 -0.01 0.00 -0.01 0.10 -0.07 -0.01 -0.01 0.00 -0.01 0.07 -0.10Excess 0.01 0.00 0.03 0.01 1.46 2.66 0.00 -0.01 0.02 0.00 1.47 2.54? Mean 0.07 0.09 0.07 0.09 0.01 0.00 0.07 0.16 0.07 0.16 0.01 0.01

0.05 0.07 0.05 0.07 0.01 0.00 0.05 0.11 0.05 0.11 0.01 0.01

Hist ogram ( 5) Sign al P rocessing Algorithm

Alph a Mag-m eas Alph a- meas Error-M ag Error-Alp ha U-select V -select U-m eas V-meas Error U Erro r V

( m/s) (deg ree) (m/s) (deg ree) (m/s) (deg ree) (m/s) (m/s) (m/s) (m/s) (m/s) (m /s)

Numb er 7633 7633 7633 7633 7633 7633 7633 7633 7633 7633 7633 7633

M axim um 110.31 13.96 110.75 14.02 2.84 1.41 110.10 25.12 110.49 25.23 2.85 2.36M inimu m 89.23 -15.34 88.44 -15.24 -2.33 -1.33 88.86 -26.45 87.85 -26.35 -2.61 -2.31M ean 99.95 -0.03 100.07 0.01 0.12 0.05 99.70 -0.06 99.82 0.02 0.12 0.08

2.97 4.03 2.99 4.03 0.40 0.23 2.98 7.01 3.01 7.03 0.41 0.40

Skew -0.01 -0.01 0.00 -0.01 -0.05 -0.18 -0.01 -0.01 -0.01 -0.01 -0.09 -0.19Excess 0.01 0.00 0.04 0.00 2.85 4.83 0.00 -0.01 0.03 -0.01 2.93 4.74? Mean 0.07 0.09 0.07 0.09 0.01 0.01 0.07 0.16 0.07 0.16 0.01 0.01

0.05 0.07 0.05 0.07 0.01 0.01 0.05 0.11 0.05 0.11 0.01 0.01

Half P ow er S ig nal Pro cessing Algo rithm

Alph a Mag-m eas Alph a- meas Error-M ag Error-Alp ha U-select V -select U-m eas V-meas Error U Erro r V

( m/s) (deg ree) (m/s) (deg ree) (m/s) (deg ree) (m/s) (m/s) (m/s) (m/s) (m/s) (m /s)

Numb er 6040 6040 6040 6040 6040 6040 6040 6040 6040 6040 6040 6040

M axim um 110.31 13.96 110.68 13.99 1.64 0.64 110.10 25.12 110.42 25.18 1.66 1.08M inimu m 89.23 -15.34 89.40 -15.29 -1.30 -0.71 88.86 -26.45 89.07 -26.41 -1.40 -1.12M ean 99.94 -0.02 100.07 0.02 0.12 0.05 99.69 -0.04 99.82 0.04 0.12 0.08

2.96 4.05 2.96 4.06 0.33 0.16 2.97 7.06 2.98 7.07 0.33 0.28

Skew 0.00 -0.01 0.01 -0.01 -0.03 -0.03 0.00 -0.01 0.01 -0.01 -0.03 -0.03Excess 0.05 0.01 0.09 0.01 -0.04 -0.12 0.04 0.00 0.07 0.01 -0.01 -0.14? Mean 0.08 0.10 0.08 0.10 0.01 0.00 0.08 0.18 0.08 0.18 0.01 0.01

0.05 0.07 0.06 0.07 0.01 0.00 0.05 0.13 0.06 0.13 0.01 0.00

True Half P ow er Sig nal Processing Alg orithm

Alph a Mag-m eas Alph a- meas Error-M ag Error-Alp ha U-select V -select U-m eas V-meas Error U Erro r V

( m/s) (deg ree) (m/s) (deg ree) (m/s) (deg ree) (m/s) (m/s) (m/s) (m/s) (m/s) (m /s)

Numb er 6040 6040 6040 6040 6040 6040 6040 6040 6040 6040 6040 6040

M axim um 110.31 13.96 110.62 13.99 1.53 0.56 110.10 25.12 110.39 25.19 1.55 1.02M inimu m 89.23 -15.34 89.39 -15.27 -1.21 -0.64 88.86 -26.45 88.97 -26.39 -1.28 -1.01M ean 99.94 -0.02 100.07 0.02 0.12 0.05 99.69 -0.04 99.82 0.04 0.12 0.08

2.96 4.05 2.96 4.05 0.28 0.14 2.97 7.06 2.97 7.07 0.28 0.24

Skew 0.00 -0.01 0.01 -0.01 -0.02 -0.06 0.00 -0.01 0.01 -0.01 -0.02 -0.05Excess 0.05 0.01 0.09 0.01 0.22 0.15 0.04 0.00 0.06 0.01 0.26 0.15? Mean 0.08 0.10 0.08 0.10 0.01 0.00 0.08 0.18 0.08 0.18 0.01 0.01

0.05 0.07 0.06 0.07 0.01 0.00 0.05 0.13 0.05 0.13 0.01 0.00

Vel- mag

St andard D ev

? Stand ard Dev

Vel- mag

St andard D ev

? Stand ard Dev

Vel- mag

St andard D ev

? Stand ard Dev

Vel- mag

St andard D ev

? Stand ard Dev
Table III.2.b. - Laser Velocimeter Results: Selected signal bursts – Statistics and First 100 selected.

III.22

Alpha Y-start Y-end Z-start Z-end U-in V-in U-select V-select

Number 10000 10000 10000 10000 10000 10000 10000 10000 9382 9382

Maximum 110.31 15.97 1.50 2.04 1.50 1.50 110.10 27.32 110.10 27.32

Minimum 89.23 -15.34 -1.50 -2.11 -1.50 -1.50 88.86 -26.45 88.86 -26.45

Mean 99.98 0.01 0.01 0.01 0.00 0.00 99.74 0.02 99.72 -0.01

2.96 4.02 0.87 0.89 0.87 0.87 2.98 7.00 2.98 6.97

Skew -0.03 0.00 -0.03 -0.01 0.01 0.01 -0.03 0.00 -0.02 0.00

Excess 0.00 -0.01 -1.21 -1.07 -1.19 -1.19 -0.01 -0.02 -0.02 -0.01

? Mean 0.06 0.08 0.02 0.02 0.02 0.02 0.06 0.14 0.06 0.14

0.04 0.06 0.01 0.01 0.01 0.01 0.04 0.10 0.04 0.10

Particle Alpha Y-start Y-end Z-start Z-end U-in V-in U-select V-select

1 102.56 7.56 -1.49 -1.09 -1.47 -1.47 101.67 13.50 101.67 13.50

2 101.80 -4.64 0.81 0.57 -1.03 -1.03 101.47 -8.24 101.47 -8.24

3 101.39 5.00 0.74 1.00 1.49 1.49 101.00 8.83 101.00 8.83

4 101.44 0.86 1.03 1.07 -0.40 -0.40 101.43 1.52 101.43 1.52

5 101.90 -0.86 -1.19 -1.24 1.01 1.01 101.89 -1.53 101.89 -1.53

6 98.63 4.11 -1.25 -1.04 0.30 0.30 98.37 7.07 98.37 7.07

7 102.65 3.79 0.61 0.81 0.37 0.37 102.42 6.78 102.42 6.78

8 100.28 4.13 1.38 1.60 0.98 0.98 100.02 7.22

9 96.60 -4.50 -0.31 -0.55 -0.94 -0.94 96.30 -7.58 96.30 -7.58

10 99.52 3.46 -1.05 -0.87 0.37 0.37 99.34 6.00 99.34 6.00

11 96.54 -3.54 0.57 0.38 -0.75 -0.75 96.36 -5.96 96.36 -5.96

12 104.99 3.63 1.36 1.55 0.24 0.24 104.78 6.64 104.78 6.64

13 98.51 1.36 1.01 1.08 -1.43 -1.43 98.48 2.34 98.48 2.34

14 97.87 2.76 -0.85 -0.71 0.80 0.80 97.76 4.71 97.76 4.71

15 98.23 -1.36 -0.18 -0.25 -0.94 -0.94 98.20 -2.34 98.20 -2.34

16 100.63 3.41 1.10 1.28 -1.22 -1.22 100.45 5.98 100.45 5.98

17 97.20 4.19 -0.36 -0.14 -1.43 -1.43 96.94 7.10 96.94 7.10

18 102.15 0.50 0.62 0.65 -0.68 -0.68 102.15 0.89 102.15 0.89

19 99.59 -9.05 0.44 -0.04 1.34 1.34 98.35 -15.66 98.35 -15.66

20 100.34 -6.08 -0.11 -0.43 0.04 0.04 99.78 -10.63 99.78 -10.63

21 98.96 -1.04 1.01 0.96 0.60 0.60 98.95 -1.79 98.95 -1.79

22 97.89 -4.40 0.63 0.40 -0.24 -0.24 97.61 -7.52 97.61 -7.52

23 99.15 1.35 0.28 0.35 0.06 0.06 99.12 2.34 99.12 2.34

24 105.90 -0.42 0.43 0.41 -0.25 -0.25 105.89 -0.78 105.89 -0.78

25 102.59 -0.69 -0.75 -0.79 -0.31 -0.31 102.58 -1.24 102.58 -1.24

26 102.14 0.06 0.22 0.22 1.28 1.28 102.14 0.12 102.14 0.12

27 99.33 -2.96 -0.78 -0.93 1.05 1.05 99.20 -5.13 99.20 -5.13

28 100.95 -4.65 1.16 0.92 -0.84 -0.84 100.62 -8.18 100.62 -8.18

29 97.03 6.65 -0.43 -0.09 -0.76 -0.76 96.38 11.24 96.38 11.24

30 101.83 -0.50 -0.28 -0.31 0.18 0.18 101.83 -0.89 101.83 -0.89

31 99.30 -2.89 -1.48 -1.64 0.33 0.33 99.18 -5.01

32 101.79 -6.21 -0.97 -1.29 0.56 0.56 101.19 -11.01 101.19 -11.01

33 95.98 9.34 1.34 1.84 -0.08 -0.08 94.71 15.57 94.71 15.57

34 99.96 4.87 0.87 1.12 -0.39 -0.39 99.60 8.48 99.60 8.48

35 104.13 -5.26 0.65 0.37 -1.15 -1.15 103.70 -9.54 103.70 -9.54

36 103.87 -1.06 -0.53 -0.58 -1.36 -1.36 103.85 -1.93 103.85 -1.93

37 104.94 -2.36 0.82 0.70 1.12 1.12 104.85 -4.31 104.85 -4.31

38 99.12 -1.10 0.82 0.77 0.55 0.55 99.10 -1.91 99.10 -1.91

39 100.92 7.91 1.30 1.72 -0.56 -0.56 99.96 13.90

40 93.67 -2.37 -0.97 -1.09 1.01 1.01 93.59 -3.88 93.59 -3.88

41 102.58 -4.01 -0.87 -1.08 1.33 1.33 102.33 -7.17 102.33 -7.17

42 104.88 5.32 -0.61 -0.33 1.09 1.09 104.43 9.73 104.43 9.73

43 96.87 8.06 0.32 0.74 0.41 0.41 95.92 13.58 95.92 13.58

44 102.20 2.07 0.91 1.01 0.04 0.04 102.13 3.69 102.13 3.69

45 101.06 3.18 1.07 1.23 -0.28 -0.28 100.91 5.60 100.91 5.60

46 102.35 1.98 0.63 0.73 -0.62 -0.62 102.29 3.54 102.29 3.54

47 105.58 -2.56 0.13 0.00 -0.33 -0.33 105.48 -4.72 105.48 -4.72

Vel-mag

Standard Dev

? Standard Dev

Vel-mag
Table III.2.b. (cont'd) - Laser Velocimeter Results: Selected signal bursts – Statistics and First 100 

selected.

III.23

48 101.61 2.14 0.82 0.93 -0.59 -0.59 101.54 3.79 101.54 3.79

49 101.24 5.01 0.05 0.31 -1.01 -1.01 100.85 8.85 100.85 8.85

50 105.53 0.47 -0.96 -0.94 0.38 0.38 105.52 0.87 105.52 0.87

51 101.78 2.43 -0.53 -0.40 -0.62 -0.62 101.69 4.32 101.69 4.32

52 99.07 3.58 -1.28 -1.09 0.54 0.54 98.87 6.18 98.87 6.18

53 100.62 3.43 -1.29 -1.11 1.13 1.13 100.44 6.03 100.44 6.03

54 98.68 -5.32 -1.44 -1.72 -0.82 -0.82 98.26 -9.15

55 104.07 5.25 -1.39 -1.11 0.84 0.84 103.64 9.53 103.64 9.53

56 98.55 -0.39 0.89 0.87 -0.08 -0.08 98.55 -0.67 98.55 -0.67

57 100.93 -6.04 -1.08 -1.39 -0.17 -0.17 100.37 -10.61 100.37 -10.61

58 101.23 -1.68 1.47 1.39 -0.34 -0.34 101.18 -2.97 101.18 -2.97

59 94.35 -3.10 -0.02 -0.18 -0.52 -0.52 94.21 -5.11 94.21 -5.11

60 103.33 2.75 -0.15 0.00 -0.65 -0.65 103.21 4.96 103.21 4.96

61 98.44 -2.96 1.20 1.05 -1.00 -1.00 98.31 -5.09 98.31 -5.09

62 103.46 0.45 1.44 1.47 -0.16 -0.16 103.45 0.81 103.45 0.81

63 102.47 4.41 0.91 1.15 0.34 0.34 102.17 7.88 102.17 7.88

64 101.78 3.50 0.92 1.10 1.49 1.49 101.59 6.22 101.59 6.22

65 101.34 -4.53 1.43 1.20 0.88 0.88 101.03 -8.01 101.03 -8.01

66 101.18 -1.50 -0.94 -1.02 -1.21 -1.21 101.14 -2.65 101.14 -2.65

67 104.19 1.09 -1.06 -1.01 -1.05 -1.05 104.17 1.99 104.17 1.99

68 101.71 -0.37 -0.92 -0.94 -0.04 -0.04 101.71 -0.65 101.71 -0.65

69 104.24 1.67 -0.88 -0.79 -0.33 -0.33 104.20 3.03 104.20 3.03

70 104.97 -3.77 0.24 0.04 -0.91 -0.91 104.74 -6.91 104.74 -6.90

71 105.06 1.60 -0.85 -0.76 0.86 0.86 105.02 2.93 105.02 2.93

72 100.14 6.57 0.85 1.19 -0.55 -0.55 99.48 11.45 99.48 11.45

73 105.34 -1.02 -0.40 -0.46 -0.51 -0.51 105.32 -1.87 105.32 -1.87

74 95.88 1.37 0.07 0.15 -0.71 -0.71 95.86 2.29 95.86 2.29

75 99.00 -6.19 -1.21 -1.54 -1.50 -1.50 98.42 -10.67 98.42 -10.67

76 100.16 1.47 0.81 0.89 0.68 0.68 100.13 2.57 100.13 2.57

77 96.80 -0.84 -0.38 -0.43 -1.41 -1.41 96.79 -1.42 96.79 -1.42

78 98.61 -1.83 -0.74 -0.84 -0.78 -0.78 98.56 -3.15 98.56 -3.15

79 99.63 -0.72 0.17 0.13 0.09 0.09 99.62 -1.25 99.62 -1.25

80 106.14 -2.08 -0.81 -0.92 -0.82 -0.82 106.07 -3.85 106.07 -3.85

81 101.79 7.53 -1.45 -1.05 -0.24 -0.24 100.91 13.34 100.91 13.34

82 97.77 5.82 -1.39 -1.08 0.11 0.11 97.26 9.92 97.26 9.92

83 96.23 -1.46 -1.10 -1.18 -1.02 -1.02 96.20 -2.45 96.20 -2.45

84 99.68 -5.59 -1.12 -1.41 0.96 0.96 99.20 -9.71 99.20 -9.71

85 99.64 -0.74 0.82 0.78 0.38 0.38 99.63 -1.29 99.63 -1.29

86 100.77 -6.75 0.62 0.26 0.45 0.45 100.07 -11.84 100.07 -11.84

87 97.16 -5.12 -0.99 -1.26 -1.32 -1.32 96.77 -8.68 96.77 -8.68

88 97.54 -1.67 -0.67 -0.76 -1.44 -1.44 97.50 -2.85 97.50 -2.84

89 98.32 -6.37 -1.11 -1.44 0.44 0.44 97.72 -10.91 97.72 -10.91

90 95.68 10.60 -0.47 0.09 -0.23 -0.23 94.04 17.60 94.04 17.60

91 101.11 -2.58 -0.22 -0.36 0.34 0.34 101.01 -4.56 101.01 -4.56

92 96.25 -1.79 -1.29 -1.39 -0.11 -0.11 96.20 -3.01 96.20 -3.01

93 103.74 6.30 0.36 0.69 1.36 1.36 103.11 11.38 103.11 11.37

94 101.04 1.68 0.53 0.62 -0.95 -0.95 100.99 2.97 100.99 2.97

95 98.01 -2.92 -1.19 -1.34 -0.93 -0.93 97.89 -5.00 97.89 -5.00

96 100.19 2.19 -0.11 0.01 -0.52 -0.52 100.12 3.82 100.11 3.82

97 99.81 -6.59 -1.08 -1.42 0.83 0.83 99.15 -11.45 99.15 -11.45

98 101.49 3.80 -0.64 -0.44 -1.36 -1.36 101.27 6.73 101.27 6.73

99 100.88 3.78 -0.34 -0.14 -0.50 -0.50 100.66 6.66 100.66 6.66

100 100.60 4.50 -1.39 -1.15 0.29 0.29 100.29 7.89 100.29 7.89
Table III.2.c. - Laser Velocimeter Results: Peak Signal Processing – Statistics and First 100 selected.

III.24

Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V

Number 4264 4264 4264 4264 4264 4264 4264 4264 4264 4264 4264 4264

Maximum 106.03 3.59 105.03 3.05 1.92 0.93 105.95 6.13 104.68 4.94 1.93 1.55

Minimum 89.95 -5.83 90.48 -5.39 -1.78 -0.73 89.83 -9.97 90.47 -8.54 -1.75 -1.29

Mean 99.73 -0.69 99.83 -0.65 0.09 0.04 99.64 -1.19 99.73 -1.12 0.09 0.07

2.76 2.42 2.83 2.41 0.70 0.38 2.77 4.21 2.83 4.19 0.70 0.66

Skew -0.21 -0.19 -0.23 -0.20 0.05 0.03 -0.21 -0.19 -0.23 -0.19 0.05 0.03

Excess -0.21 -1.02 -0.28 -1.06 -1.08 -1.14 -0.22 -1.03 -0.29 -1.07 -1.09 -1.15

? Mean 0.08 0.07 0.09 0.07 0.02 0.01 0.08 0.13 0.09 0.13 0.02 0.02

0.06 0.04 0.06 0.04 0.01 0.01 0.06 0.06 0.06 0.06 0.01 0.01

Particle Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V

2 101.80 -4.64 102.67 -4.77 0.87 -0.13 101.47 -8.24 102.32 -8.54 0.85 -0.30

4 101.44 0.86 102.32 0.25 0.87 -0.61 101.43 1.52 102.32 0.45 0.88 -1.08

9 96.60 -4.50 97.95 -5.00 1.35 -0.50 96.30 -7.58 97.58 -8.54 1.28 -0.96

11 96.54 -3.54 95.42 -3.78 -1.13 -0.24 96.36 -5.96 95.21 -6.29 -1.15 -0.33

14 97.87 2.76 97.70 2.90 -0.17 0.14 97.76 4.71 97.58 4.94 -0.18 0.23

15 98.23 -1.36 97.60 -1.06 -0.63 0.31 98.20 -2.34 97.58 -1.80 -0.62 0.54

18 102.15 0.50 102.32 0.25 0.17 -0.25 102.15 0.89 102.32 0.45 0.17 -0.44

21 98.96 -1.04 99.96 -1.03 1.00 0.01 98.95 -1.79 99.95 -1.80 1.00 -0.01

22 97.90 -4.40 97.95 -5.00 0.06 -0.60 97.61 -7.52 97.58 -8.54 -0.03 -1.02

23 99.15 1.35 99.98 1.55 0.84 0.19 99.12 2.34 99.95 2.70 0.83 0.36

25 102.59 -0.69 102.33 -1.01 -0.26 -0.31 102.58 -1.24 102.32 -1.80 -0.26 -0.56

26 102.14 0.07 102.32 0.25 0.18 0.19 102.14 0.12 102.32 0.45 0.18 0.33

30 101.83 -0.50 102.33 -1.01 0.50 -0.50 101.83 -0.89 102.32 -1.80 0.49 -0.90

35 104.14 -5.26 105.03 -4.66 0.90 0.60 103.70 -9.54 104.68 -8.54 0.99 1.00

38 99.12 -1.10 99.96 -1.03 0.85 0.07 99.10 -1.91 99.95 -1.80 0.85 0.11

44 102.20 2.07 102.35 1.51 0.15 -0.56 102.13 3.69 102.32 2.70 0.18 -0.99

45 101.06 3.18 100.07 2.83 -0.99 -0.35 100.91 5.60 99.95 4.94 -0.96 -0.66

46 102.35 1.98 102.35 1.51 0.00 -0.47 102.29 3.54 102.32 2.70 0.03 -0.84

47 105.58 -2.56 104.76 -2.21 -0.82 0.35 105.48 -4.72 104.68 -4.04 -0.79 0.68

48 101.61 2.14 102.35 1.51 0.74 -0.63 101.54 3.79 102.32 2.70 0.77 -1.09

50 105.53 0.47 104.69 0.25 -0.84 -0.23 105.52 0.87 104.68 0.45 -0.84 -0.42

51 101.78 2.43 102.44 2.77 0.65 0.33 101.69 4.32 102.32 4.94 0.63 0.62

56 98.55 -0.39 97.58 0.26 -0.97 0.65 98.55 -0.67 97.58 0.45 -0.97 1.12

59 94.35 -3.10 95.30 -2.43 0.95 0.67 94.21 -5.11 95.21 -4.04 1.00 1.07

60 103.33 2.75 102.44 2.77 -0.90 0.01 103.21 4.96 102.32 4.94 -0.90 -0.02

68 101.71 -0.37 102.33 -1.01 0.62 -0.64 101.71 -0.65 102.32 -1.80 0.61 -1.15

69 104.24 1.67 104.72 1.48 0.48 -0.19 104.20 3.03 104.68 2.70 0.49 -0.33

70 104.97 -3.77 104.87 -3.44 -0.10 0.33 104.74 -6.91 104.68 -6.29 -0.06 0.62

71 105.06 1.60 104.72 1.48 -0.34 -0.12 105.02 2.93 104.68 2.70 -0.33 -0.23

73 105.34 -1.02 104.70 -0.98 -0.64 0.03 105.32 -1.87 104.68 -1.80 -0.63 0.07

74 95.89 1.37 95.25 1.62 -0.64 0.25 95.86 2.29 95.21 2.70 -0.65 0.41

76 100.16 1.47 99.98 1.55 -0.18 0.08 100.13 2.57 99.95 2.70 -0.18 0.13

77 96.80 -0.84 97.60 -1.06 0.80 -0.21 96.79 -1.42 97.58 -1.80 0.79 -0.38

78 98.61 -1.83 97.66 -2.37 -0.95 -0.54 98.56 -3.15 97.58 -4.04 -0.98 -0.89

79 99.63 -0.72 99.96 -1.03 0.34 -0.31 99.62 -1.25 99.95 -1.80 0.33 -0.55

85 99.64 -0.74 99.96 -1.03 0.32 -0.29 99.63 -1.29 99.95 -1.80 0.31 -0.51

91 101.11 -2.58 102.40 -2.26 1.28 0.32 101.01 -4.56 102.32 -4.04 1.31 0.51

94 101.04 1.68 99.98 1.55 -1.05 -0.14 100.99 2.97 99.95 2.70 -1.05 -0.27

96 100.19 2.19 100.07 2.83 -0.12 0.65 100.12 3.82 99.95 4.94 -0.17 1.12

Vel-mag

Standard Dev

? Standard Dev

Vel-mag
Table III.2.d. - Laser Velocimeter Results: Gaussian Signal Processing – Statistics and First 100 selected.

III.25

Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V

Number 5909 5909 5909 5909 5909 5909 5909 5909 5909 5909 5909 5909

Maximum 108.21 8.91 108.08 8.76 1.61 0.77 108.12 15.19 107.31 14.23 1.70 1.33

Minimum 89.23 -11.93 88.64 -11.77 -1.42 -0.62 88.86 -20.88 88.35 -20.06 -1.39 -1.08

Mean 99.90 -0.18 100.01 -0.13 0.11 0.04 99.68 -0.31 99.78 -0.23 0.11 0.08

2.91 3.83 2.96 3.83 0.51 0.28 2.93 6.66 2.97 6.67 0.51 0.48

Skew -0.07 -0.17 -0.07 -0.18 0.04 0.02 -0.07 -0.17 -0.07 -0.18 0.04 0.01

Excess -0.07 -0.34 -0.09 -0.34 -0.97 -1.07 -0.08 -0.35 -0.08 -0.35 -0.97 -1.08

? Mean 0.08 0.10 0.08 0.10 0.01 0.01 0.08 0.17 0.08 0.17 0.01 0.01

0.05 0.06 0.05 0.06 0.01 0.00 0.05 0.11 0.05 0.11 0.01 0.01

Particle Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V

2 101.80 -4.64 102.55 -4.65 0.74 -0.01 101.47 -8.24 102.21 -8.31 0.74 -0.07

4 101.44 0.86 102.05 0.41 0.61 -0.46 101.43 1.52 102.05 0.72 0.62 -0.80

6 98.63 4.11 98.15 4.19 -0.48 0.08 98.37 7.07 97.88 7.18 -0.49 0.10

7 102.65 3.79 102.62 3.96 -0.03 0.17 102.42 6.78 102.38 7.09 -0.05 0.31

9 96.60 -4.50 97.57 -4.82 0.97 -0.32 96.30 -7.58 97.22 -8.20 0.92 -0.62

10 99.53 3.46 100.05 3.96 0.53 0.50 99.34 6.00 99.82 6.90 0.47 0.90

11 96.54 -3.54 95.74 -3.71 -0.80 -0.17 96.36 -5.96 95.54 -6.20 -0.82 -0.24

14 97.87 2.76 97.67 2.88 -0.21 0.12 97.76 4.71 97.54 4.91 -0.22 0.20

15 98.23 -1.36 97.84 -1.10 -0.39 0.26 98.20 -2.34 97.82 -1.89 -0.38 0.45

18 102.15 0.50 102.36 0.31 0.21 -0.19 102.15 0.89 102.36 0.55 0.21 -0.34

19 99.59 -9.05 99.07 -8.96 -0.52 0.09 98.35 -15.66 97.86 -15.43 -0.49 0.23

20 100.34 -6.08 100.50 -6.12 0.15 -0.04 99.78 -10.63 99.92 -10.71 0.14 -0.08

21 98.96 -1.04 99.76 -0.97 0.80 0.07 98.95 -1.79 99.75 -1.69 0.80 0.10

22 97.90 -4.40 97.96 -4.82 0.07 -0.42 97.61 -7.52 97.62 -8.24 0.01 -0.72

23 99.15 1.35 99.82 1.51 0.67 0.16 99.12 2.34 99.78 2.63 0.66 0.29

24 105.90 -0.42 106.83 -0.84 0.94 -0.41 105.89 -0.78 106.82 -1.56 0.93 -0.78

25 102.59 -0.69 102.44 -0.92 -0.14 -0.23 102.58 -1.24 102.43 -1.64 -0.15 -0.40

26 102.14 0.07 102.27 0.22 0.13 0.15 102.14 0.12 102.27 0.39 0.13 0.27

29 97.03 6.65 97.95 6.78 0.92 0.13 96.38 11.24 97.26 11.57 0.88 0.33

30 101.83 -0.50 102.23 -0.88 0.40 -0.38 101.83 -0.89 102.22 -1.57 0.39 -0.67

34 99.96 4.87 100.33 5.27 0.37 0.40 99.60 8.48 99.90 9.21 0.31 0.73

35 104.14 -5.26 104.85 -4.77 0.72 0.49 103.70 -9.54 104.49 -8.71 0.79 0.83

38 99.12 -1.10 99.71 -1.03 0.59 0.07 99.10 -1.91 99.69 -1.79 0.59 0.12

42 104.88 5.32 105.15 5.20 0.27 -0.12 104.43 9.73 104.72 9.54 0.29 -0.19

43 96.88 8.06 96.44 8.25 -0.44 0.20 95.92 13.58 95.44 13.84 -0.48 0.27

44 102.20 2.07 102.30 1.66 0.10 -0.41 102.13 3.69 102.25 2.96 0.12 -0.73

45 101.06 3.18 100.41 2.95 -0.65 -0.22 100.91 5.60 100.28 5.17 -0.63 -0.43

46 102.35 1.98 102.44 1.67 0.09 -0.31 102.29 3.54 102.40 2.98 0.11 -0.56

47 105.58 -2.56 104.94 -2.28 -0.64 0.28 105.48 -4.72 104.86 -4.17 -0.61 0.55

48 101.61 2.14 102.18 1.69 0.57 -0.45 101.54 3.79 102.14 3.01 0.60 -0.78

49 101.24 5.01 100.73 5.29 -0.51 0.28 100.85 8.85 100.30 9.29 -0.55 0.44

50 105.53 0.47 104.97 0.33 -0.56 -0.14 105.52 0.87 104.97 0.60 -0.56 -0.27

51 101.78 2.43 102.26 2.69 0.47 0.25 101.69 4.32 102.14 4.79 0.45 0.47

56 98.55 -0.39 97.87 0.10 -0.68 0.49 98.55 -0.67 97.87 0.17 -0.68 0.84

59 94.35 -3.10 95.02 -2.62 0.68 0.48 94.21 -5.11 94.92 -4.35 0.72 0.76

60 103.33 2.75 102.74 2.77 -0.59 0.02 103.21 4.96 102.62 4.97 -0.59 0.01

63 102.47 4.41 102.56 4.16 0.09 -0.25 102.17 7.88 102.29 7.43 0.13 -0.45

68 101.71 -0.37 102.24 -0.88 0.53 -0.51 101.71 -0.65 102.23 -1.56 0.52 -0.91

69 104.24 1.67 104.61 1.55 0.36 -0.11 104.20 3.03 104.57 2.84 0.37 -0.19

70 104.97 -3.77 104.91 -3.51 -0.06 0.26 104.74 -6.91 104.72 -6.42 -0.03 0.48

71 105.06 1.60 104.82 1.54 -0.23 -0.06 105.02 2.93 104.79 2.81 -0.23 -0.12

72 100.14 6.57 100.47 6.69 0.33 0.12 99.48 11.45 99.79 11.70 0.31 0.24

73 105.34 -1.02 104.93 -0.99 -0.41 0.03 105.32 -1.87 104.91 -1.80 -0.41 0.07

74 95.89 1.37 95.45 1.56 -0.43 0.20 95.86 2.29 95.42 2.61 -0.44 0.32

76 100.16 1.47 100.11 1.53 -0.05 0.06 100.13 2.57 100.08 2.67 -0.05 0.10

77 96.80 -0.84 97.42 -0.92 0.62 -0.08 96.79 -1.42 97.41 -1.57 0.62 -0.14

78 98.61 -1.83 98.02 -2.23 -0.59 -0.40 98.56 -3.15 97.95 -3.82 -0.61 -0.66

79 99.63 -0.72 99.90 -0.92 0.28 -0.20 99.62 -1.25 99.89 -1.60 0.27 -0.36

80 106.14 -2.08 106.86 -2.19 0.72 -0.11 106.07 -3.85 106.78 -4.09 0.71 -0.24

81 101.79 7.53 103.07 7.73 1.28 0.21 100.91 13.34 102.13 13.87 1.22 0.54

85 99.64 -0.74 99.92 -0.93 0.28 -0.19 99.63 -1.29 99.91 -1.62 0.28 -0.33

86 100.77 -6.75 100.60 -6.29 -0.17 0.46 100.07 -11.84 99.99 -11.02 -0.08 0.82

91 101.11 -2.58 102.13 -2.33 1.01 0.26 101.01 -4.56 102.04 -4.14 1.03 0.41

94 101.04 1.68 100.30 1.61 -0.74 -0.07 100.99 2.97 100.26 2.82 -0.73 -0.15

96 100.19 2.19 100.12 2.66 -0.07 0.48 100.12 3.82 100.01 4.65 -0.11 0.83

99 100.88 3.79 100.41 4.06 -0.48 0.27 100.66 6.66 100.15 7.10 -0.51 0.44

Vel-mag

Standard Dev

? Standard Dev

Vel-mag
Table III.2.e. - Laser Velocimeter Results: Histogram (3) Signal Processing – Statistics and First 100 

selected.

III.26

Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V

Number 7633 7633 7633 7633 7633 7633 7633 7633 7633 7633 7633 7633

Maximum 110.31 13.96 110.59 14.06 1.85 1.02 110.10 25.12 109.89 25.20 1.85 1.71

Minimum 89.23 -15.34 88.96 -15.20 -1.53 -1.14 88.86 -26.45 88.40 -26.36 -1.56 -1.97

Mean 99.95 -0.03 100.06 0.01 0.11 0.05 99.70 -0.06 99.81 0.02 0.11 0.08

2.97 4.03 2.98 4.03 0.31 0.18 2.98 7.01 3.00 7.02 0.31 0.31

Skew -0.01 -0.01 0.00 -0.01 0.10 -0.07 -0.01 -0.01 0.00 -0.01 0.07 -0.10

Excess 0.01 0.00 0.03 0.01 1.46 2.66 0.00 -0.01 0.02 0.00 1.47 2.54

? Mean 0.07 0.09 0.07 0.09 0.01 0.00 0.07 0.16 0.07 0.16 0.01 0.01

0.05 0.07 0.05 0.07 0.01 0.00 0.05 0.11 0.05 0.11 0.01 0.01

Particle Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V

2 101.80 -4.64 102.34 -4.40 0.54 0.24 101.47 -8.24 102.04 -7.85 0.57 0.39

4 101.44 0.86 101.55 0.65 0.11 -0.21 101.43 1.52 101.54 1.15 0.11 -0.37

6 98.63 4.11 98.57 4.09 -0.06 -0.03 98.37 7.07 98.32 7.02 -0.06 -0.05

7 102.65 3.79 102.75 3.84 0.10 0.06 102.42 6.78 102.52 6.89 0.09 0.11

9 96.60 -4.50 97.12 -4.56 0.52 -0.06 96.30 -7.58 96.81 -7.72 0.51 -0.14

10 99.53 3.46 99.83 3.72 0.31 0.27 99.34 6.00 99.62 6.48 0.28 0.48

11 96.54 -3.54 96.24 -3.64 -0.30 -0.10 96.36 -5.96 96.05 -6.12 -0.31 -0.15

14 97.87 2.76 97.58 2.87 -0.29 0.11 97.76 4.71 97.46 4.89 -0.30 0.18

15 98.23 -1.36 98.13 -1.14 -0.10 0.23 98.20 -2.34 98.11 -1.95 -0.09 0.39

17 97.20 4.19 97.16 4.22 -0.04 0.03 96.94 7.10 96.90 7.15 -0.04 0.05

18 102.15 0.50 102.42 0.39 0.27 -0.11 102.15 0.89 102.41 0.70 0.27 -0.19

19 99.59 -9.05 99.52 -9.07 -0.07 -0.02 98.35 -15.66 98.27 -15.69 -0.08 -0.03

20 100.34 -6.08 100.46 -6.04 0.11 0.04 99.78 -10.63 99.90 -10.58 0.12 0.05

21 98.96 -1.04 99.51 -0.83 0.54 0.21 98.95 -1.79 99.49 -1.44 0.55 0.35

22 97.90 -4.40 97.97 -4.57 0.07 -0.16 97.61 -7.52 97.66 -7.80 0.05 -0.28

23 99.15 1.35 99.61 1.45 0.46 0.10 99.12 2.34 99.58 2.52 0.46 0.18

24 105.90 -0.42 106.40 -0.60 0.51 -0.18 105.89 -0.78 106.40 -1.11 0.51 -0.33

25 102.59 -0.69 102.59 -0.82 0.00 -0.12 102.58 -1.24 102.58 -1.46 0.00 -0.22

26 102.14 0.07 102.27 0.15 0.13 0.09 102.14 0.12 102.27 0.27 0.13 0.16

27 99.33 -2.96 99.66 -2.72 0.33 0.24 99.20 -5.13 99.54 -4.74 0.35 0.40

28 100.95 -4.65 100.76 -4.74 -0.20 -0.09 100.62 -8.18 100.41 -8.32 -0.21 -0.14

29 97.03 6.65 97.65 6.70 0.61 0.05 96.38 11.24 96.98 11.39 0.60 0.15

30 101.83 -0.50 102.03 -0.66 0.20 -0.16 101.83 -0.89 102.02 -1.17 0.20 -0.28

32 101.79 -6.21 102.23 -6.28 0.44 -0.07 101.19 -11.01 101.62 -11.17 0.42 -0.16

34 99.96 4.87 100.24 5.05 0.29 0.19 99.60 8.48 99.85 8.83 0.26 0.35

35 104.14 -5.26 104.53 -4.88 0.39 0.38 103.70 -9.54 104.15 -8.89 0.45 0.65

36 103.87 -1.06 103.50 -1.05 -0.37 0.01 103.85 -1.93 103.48 -1.90 -0.37 0.03

37 104.94 -2.36 104.95 -2.27 0.01 0.08 104.85 -4.31 104.87 -4.17 0.02 0.15

38 99.12 -1.10 99.24 -1.01 0.13 0.09 99.10 -1.91 99.23 -1.75 0.13 0.15

40 93.67 -2.37 93.73 -2.78 0.06 -0.41 93.59 -3.88 93.62 -4.55 0.03 -0.67

42 104.88 5.32 105.31 5.29 0.43 -0.03 104.43 9.73 104.86 9.71 0.43 -0.02

43 96.88 8.06 96.71 8.15 -0.16 0.09 95.92 13.58 95.74 13.71 -0.18 0.13

44 102.20 2.07 102.20 1.93 0.00 -0.14 102.13 3.69 102.14 3.45 0.01 -0.24

45 101.06 3.18 100.85 3.16 -0.21 -0.02 100.91 5.60 100.70 5.56 -0.21 -0.04

46 102.35 1.98 102.58 1.96 0.23 -0.02 102.29 3.54 102.52 3.51 0.23 -0.03

47 105.58 -2.56 105.29 -2.42 -0.30 0.15 105.48 -4.72 105.19 -4.44 -0.28 0.28

48 101.61 2.14 101.99 1.94 0.38 -0.20 101.54 3.79 101.94 3.44 0.39 -0.35

49 101.24 5.01 101.18 5.13 -0.06 0.12 100.85 8.85 100.77 9.05 -0.08 0.20

50 105.53 0.47 105.41 0.47 -0.12 0.00 105.52 0.87 105.41 0.86 -0.12 -0.01

51 101.78 2.43 102.05 2.56 0.27 0.12 101.69 4.32 101.95 4.55 0.26 0.23

52 99.07 3.58 99.59 3.66 0.52 0.09 98.87 6.18 99.38 6.36 0.51 0.18

56 98.55 -0.39 98.34 -0.14 -0.21 0.25 98.55 -0.67 98.34 -0.25 -0.21 0.42

57 100.93 -6.04 100.93 -5.91 0.00 0.13 100.37 -10.61 100.39 -10.39 0.02 0.23

59 94.35 -3.10 94.71 -2.88 0.36 0.22 94.21 -5.11 94.59 -4.76 0.38 0.35

60 103.33 2.75 103.19 2.78 -0.14 0.03 103.21 4.96 103.07 5.01 -0.15 0.05

63 102.47 4.41 102.56 4.38 0.09 -0.03 102.17 7.88 102.26 7.84 0.09 -0.04

68 101.71 -0.37 102.04 -0.64 0.32 -0.27 101.71 -0.65 102.03 -1.14 0.32 -0.49

69 104.24 1.67 104.48 1.70 0.24 0.03 104.20 3.03 104.43 3.10 0.24 0.07

70 104.97 -3.77 104.94 -3.63 -0.03 0.14 104.74 -6.91 104.73 -6.64 -0.02 0.27

71 105.06 1.60 104.95 1.63 -0.11 0.03 105.02 2.93 104.91 2.98 -0.11 0.06

72 100.14 6.57 100.38 6.75 0.24 0.19 99.48 11.45 99.68 11.81 0.20 0.35

73 105.34 -1.02 105.29 -0.98 -0.05 0.03 105.32 -1.87 105.27 -1.81 -0.05 0.06

74 95.89 1.37 95.75 1.48 -0.13 0.11 95.86 2.29 95.72 2.47 -0.14 0.18

76 100.16 1.47 100.28 1.50 0.12 0.03 100.13 2.57 100.25 2.63 0.12 0.06

77 96.80 -0.84 96.77 -0.65 -0.02 0.19 96.79 -1.42 96.77 -1.10 -0.02 0.32

78 98.61 -1.83 98.56 -2.02 -0.05 -0.19 98.56 -3.15 98.50 -3.48 -0.06 -0.32

79 99.63 -0.72 99.83 -0.74 0.21 -0.02 99.62 -1.25 99.82 -1.28 0.21 -0.04

80 106.14 -2.08 106.40 -2.29 0.26 -0.21 106.07 -3.85 106.31 -4.25 0.24 -0.41

81 101.79 7.53 102.87 7.66 1.08 0.14 100.91 13.34 101.95 13.72 1.04 0.38

82 97.77 5.82 98.01 5.55 0.24 -0.27 97.26 9.92 97.55 9.48 0.29 -0.44

85 99.64 -0.74 99.88 -0.73 0.24 0.01 99.63 -1.29 99.87 -1.28 0.24 0.01

86 100.77 -6.75 100.75 -6.49 -0.02 0.26 100.07 -11.84 100.10 -11.38 0.03 0.46

88 97.54 -1.67 97.51 -0.94 -0.04 0.73 97.50 -2.85 97.49 -1.60 -0.01 1.24

89 98.32 -6.37 98.14 -6.30 -0.18 0.07 97.72 -10.91 97.55 -10.77 -0.17 0.14

90 95.68 10.60 96.06 10.70 0.39 0.10 94.04 17.60 94.39 17.84 0.35 0.24

91 101.11 -2.58 101.64 -2.44 0.53 0.15 101.01 -4.56 101.55 -4.32 0.54 0.23

92 96.25 -1.79 95.50 -1.46 -0.75 0.33 96.20 -3.01 95.47 -2.44 -0.74 0.57

93 103.74 6.30 103.33 6.21 -0.41 -0.09 103.11 11.38 102.72 11.18 -0.39 -0.20

94 101.04 1.68 100.84 1.68 -0.19 -0.01 100.99 2.97 100.80 2.95 -0.19 -0.02

96 100.19 2.19 100.16 2.40 -0.02 0.21 100.12 3.82 100.08 4.19 -0.04 0.37

97 99.81 -6.59 99.71 -5.93 -0.10 0.66 99.15 -11.45 99.18 -10.30 0.02 1.15

98 101.49 3.80 101.60 3.97 0.10 0.17 101.27 6.73 101.35 7.04 0.08 0.31

99 100.88 3.79 100.70 3.96 -0.18 0.18 100.66 6.66 100.46 6.96 -0.20 0.30

100 100.60 4.50 100.60 4.37 0.00 -0.13 100.29 7.89 100.31 7.66 0.02 -0.23

Vel-mag

Standard Dev

? Standard Dev

Vel-mag
Table III.2.f. - Laser Velocimeter Results: Histogram (5) Signal Processing – Statistics and First 100 

selected.

III.27

Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V

Number 7633 7633 7633 7633 7633 7633 7633 7633 7633 7633 7633 7633

Maximum 110.31 13.96 110.75 14.02 2.84 1.41 110.10 25.12 110.49 25.23 2.85 2.36

Minimum 89.23 -15.34 88.44 -15.24 -2.33 -1.33 88.86 -26.45 87.85 -26.35 -2.61 -2.31

Mean 99.95 -0.03 100.07 0.01 0.12 0.05 99.70 -0.06 99.82 0.02 0.12 0.08

2.97 4.03 2.99 4.03 0.40 0.23 2.98 7.01 3.01 7.03 0.41 0.40

Skew -0.01 -0.01 0.00 -0.01 -0.05 -0.18 -0.01 -0.01 -0.01 -0.01 -0.09 -0.19

Excess 0.01 0.00 0.04 0.00 2.85 4.83 0.00 -0.01 0.03 -0.01 2.93 4.74

? Mean 0.07 0.09 0.07 0.09 0.01 0.01 0.07 0.16 0.07 0.16 0.01 0.01

0.05 0.07 0.05 0.07 0.01 0.01 0.05 0.11 0.05 0.11 0.01 0.01

Particle Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V

2 101.80 -4.64 102.65 -4.01 0.85 0.63 101.47 -8.24 102.40 -7.18 0.93 1.06

4 101.44 0.86 100.83 0.85 -0.62 -0.01 101.43 1.52 100.82 1.49 -0.62 -0.03

6 98.63 4.11 98.81 3.92 0.19 -0.19 98.37 7.07 98.58 6.76 0.21 -0.31

7 102.65 3.79 103.02 3.78 0.38 -0.01 102.42 6.78 102.80 6.79 0.38 0.01

9 96.60 -4.50 97.04 -4.38 0.44 0.12 96.30 -7.58 96.76 -7.41 0.46 0.17

10 99.53 3.46 99.75 3.49 0.22 0.03 99.34 6.00 99.56 6.07 0.22 0.07

11 96.54 -3.54 96.55 -3.63 0.01 -0.09 96.36 -5.96 96.36 -6.12 0.00 -0.15

14 97.87 2.76 97.80 2.85 -0.07 0.09 97.76 4.71 97.68 4.87 -0.08 0.15

15 98.23 -1.36 98.18 -1.13 -0.05 0.24 98.20 -2.34 98.16 -1.93 -0.04 0.40

17 97.20 4.19 96.75 4.24 -0.45 0.05 96.94 7.10 96.48 7.15 -0.45 0.05

18 102.15 0.50 102.44 0.43 0.29 -0.07 102.15 0.89 102.44 0.78 0.29 -0.12

19 99.59 -9.05 99.13 -9.31 -0.46 -0.26 98.35 -15.66 97.82 -16.03 -0.53 -0.37

20 100.34 -6.08 100.43 -5.92 0.09 0.16 99.78 -10.63 99.89 -10.36 0.11 0.27

21 98.96 -1.04 99.47 -0.50 0.50 0.54 98.95 -1.79 99.46 -0.87 0.52 0.92

22 97.90 -4.40 97.95 -4.39 0.05 0.02 97.61 -7.52 97.66 -7.49 0.05 0.02

23 99.15 1.35 99.59 1.32 0.45 -0.03 99.12 2.34 99.57 2.30 0.45 -0.04

24 105.90 -0.42 106.00 -0.35 0.10 0.07 105.89 -0.78 105.99 -0.65 0.10 0.13

25 102.59 -0.69 102.34 -0.80 -0.25 -0.11 102.58 -1.24 102.33 -1.44 -0.25 -0.19

26 102.14 0.07 102.27 0.02 0.13 -0.05 102.14 0.12 102.27 0.03 0.13 -0.09

27 99.33 -2.96 99.96 -2.80 0.64 0.16 99.20 -5.13 99.85 -4.88 0.65 0.25

28 100.95 -4.65 100.90 -4.69 -0.05 -0.04 100.62 -8.18 100.56 -8.25 -0.06 -0.07

29 97.03 6.65 97.62 6.65 0.59 0.00 96.38 11.24 96.96 11.31 0.59 0.07

30 101.83 -0.50 101.67 -0.49 -0.16 0.01 101.83 -0.89 101.67 -0.87 -0.16 0.03

32 101.79 -6.21 101.89 -6.51 0.10 -0.31 101.19 -11.01 101.23 -11.56 0.04 -0.55

34 99.96 4.87 100.61 4.85 0.65 -0.02 99.60 8.48 100.25 8.50 0.65 0.02

35 104.14 -5.26 104.07 -4.97 -0.07 0.29 103.70 -9.54 103.68 -9.01 -0.02 0.53

36 103.87 -1.06 102.92 -1.18 -0.95 -0.11 103.85 -1.93 102.90 -2.11 -0.96 -0.19

37 104.94 -2.36 104.95 -2.27 0.01 0.09 104.85 -4.31 104.87 -4.15 0.02 0.16

38 99.12 -1.10 98.99 -0.96 -0.13 0.14 99.10 -1.91 98.97 -1.67 -0.13 0.24

40 93.67 -2.37 93.36 -3.31 -0.31 -0.94 93.59 -3.88 93.21 -5.39 -0.38 -1.51

42 104.88 5.32 105.33 5.43 0.45 0.11 104.43 9.73 104.86 9.97 0.43 0.24

43 96.88 8.06 96.96 8.09 0.08 0.03 95.92 13.58 95.99 13.65 0.07 0.07

44 102.20 2.07 101.94 2.16 -0.26 0.09 102.13 3.69 101.87 3.84 -0.26 0.15

45 101.06 3.18 101.14 3.35 0.08 0.18 100.91 5.60 100.96 5.91 0.06 0.32

46 102.35 1.98 102.80 2.15 0.45 0.17 102.29 3.54 102.73 3.86 0.44 0.32

47 105.58 -2.56 105.73 -2.59 0.15 -0.03 105.48 -4.72 105.62 -4.77 0.14 -0.05

48 101.61 2.14 102.03 2.12 0.42 -0.02 101.54 3.79 101.96 3.77 0.42 -0.02

49 101.24 5.01 101.45 5.06 0.21 0.05 100.85 8.85 101.06 8.95 0.21 0.10

50 105.53 0.47 105.22 0.54 -0.31 0.06 105.52 0.87 105.22 0.98 -0.31 0.11

51 101.78 2.43 102.04 2.50 0.26 0.07 101.69 4.32 101.94 4.45 0.25 0.13

52 99.07 3.58 100.03 3.33 0.96 -0.25 98.87 6.18 99.86 5.81 0.99 -0.37

56 98.55 -0.39 98.68 -0.21 0.13 0.19 98.55 -0.67 98.68 -0.35 0.13 0.32

57 100.93 -6.04 101.37 -5.70 0.44 0.34 100.37 -10.61 100.87 -10.07 0.50 0.54

59 94.35 -3.10 94.72 -3.02 0.38 0.09 94.21 -5.11 94.59 -4.99 0.38 0.12

60 103.33 2.75 103.54 2.78 0.21 0.03 103.21 4.96 103.42 5.02 0.20 0.06

63 102.47 4.41 102.25 4.61 -0.22 0.20 102.17 7.88 101.92 8.22 -0.24 0.34

68 101.71 -0.37 101.89 -0.42 0.18 -0.05 101.71 -0.65 101.89 -0.74 0.18 -0.09

69 104.24 1.67 104.58 1.76 0.33 0.09 104.20 3.03 104.53 3.21 0.33 0.18

70 104.97 -3.77 104.94 -3.67 -0.03 0.10 104.74 -6.91 104.73 -6.72 -0.01 0.18

71 105.06 1.60 104.95 1.67 -0.11 0.07 105.02 2.93 104.91 3.06 -0.11 0.13

72 100.14 6.57 100.17 6.94 0.03 0.37 99.48 11.45 99.43 12.10 -0.05 0.65

73 105.34 -1.02 105.43 -0.98 0.10 0.03 105.32 -1.87 105.42 -1.81 0.10 0.06

74 95.89 1.37 96.00 1.34 0.11 -0.03 95.86 2.29 95.97 2.24 0.11 -0.05

76 100.16 1.47 100.54 1.51 0.38 0.04 100.13 2.57 100.51 2.64 0.38 0.07

77 96.80 -0.84 96.42 -0.27 -0.38 0.57 96.79 -1.42 96.42 -0.46 -0.37 0.97

78 98.61 -1.83 98.79 -1.66 0.18 0.17 98.56 -3.15 98.75 -2.87 0.19 0.29

79 99.63 -0.72 99.85 -0.62 0.23 0.10 99.62 -1.25 99.85 -1.08 0.23 0.16

80 106.14 -2.08 105.86 -2.60 -0.28 -0.52 106.07 -3.85 105.75 -4.80 -0.32 -0.95

81 101.79 7.53 102.49 7.47 0.70 -0.06 100.91 13.34 101.62 13.33 0.71 -0.01

82 97.77 5.82 98.42 5.53 0.65 -0.29 97.26 9.92 97.96 9.48 0.70 -0.44

85 99.64 -0.74 99.89 -0.53 0.25 0.21 99.63 -1.29 99.89 -0.92 0.25 0.37

86 100.77 -6.75 100.81 -6.55 0.04 0.20 100.07 -11.84 100.15 -11.50 0.08 0.34

88 97.54 -1.67 98.65 -0.78 1.11 0.89 97.50 -2.85 98.64 -1.35 1.14 1.49

89 98.32 -6.37 98.14 -6.55 -0.19 -0.18 97.72 -10.91 97.50 -11.20 -0.22 -0.29

90 95.68 10.60 95.70 10.61 0.02 0.01 94.04 17.60 94.06 17.62 0.02 0.02

91 101.11 -2.58 101.01 -2.49 -0.10 0.09 101.01 -4.56 100.92 -4.40 -0.09 0.16

92 96.25 -1.79 95.59 -1.85 -0.67 -0.06 96.20 -3.01 95.54 -3.08 -0.67 -0.08

93 103.74 6.30 103.71 6.05 -0.03 -0.25 103.11 11.38 103.13 10.92 0.02 -0.45

94 101.04 1.68 101.19 1.69 0.15 0.00 100.99 2.97 101.15 2.98 0.15 0.01

96 100.19 2.19 100.14 2.21 -0.05 0.03 100.12 3.82 100.07 3.87 -0.05 0.04

97 99.81 -6.59 100.06 -6.01 0.25 0.57 99.15 -11.45 99.51 -10.48 0.36 0.97

98 101.49 3.80 102.33 3.98 0.83 0.17 101.27 6.73 102.08 7.09 0.81 0.36

99 100.88 3.79 100.78 3.93 -0.10 0.15 100.66 6.66 100.54 6.91 -0.12 0.25

100 100.60 4.50 100.89 4.54 0.29 0.05 100.29 7.89 100.58 7.99 0.29 0.11

Vel-mag

Standard Dev

? Standard Dev

Vel-mag
Table III.2.g. - Laser Velocimeter Results: Half Power Signal Processing – Statistics and First 100 

selected.

III.28

Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V

Number 6040 6040 6040 6040 6040 6040 6040 6040 6040 6040 6040 6040

Maximum 110.31 13.96 110.68 13.99 1.64 0.64 110.10 25.12 110.42 25.18 1.66 1.08

Minimum 89.23 -15.34 89.40 -15.29 -1.30 -0.71 88.86 -26.45 89.07 -26.41 -1.40 -1.12

Mean 99.94 -0.02 100.07 0.02 0.12 0.05 99.69 -0.04 99.82 0.04 0.12 0.08

2.96 4.05 2.96 4.06 0.33 0.16 2.97 7.06 2.98 7.07 0.33 0.28

Skew 0.00 -0.01 0.01 -0.01 -0.03 -0.03 0.00 -0.01 0.01 -0.01 -0.03 -0.03

Excess 0.05 0.01 0.09 0.01 -0.04 -0.12 0.04 0.00 0.07 0.01 -0.01 -0.14

? Mean 0.08 0.10 0.08 0.10 0.01 0.00 0.08 0.18 0.08 0.18 0.01 0.01

0.05 0.07 0.06 0.07 0.01 0.00 0.05 0.13 0.06 0.13 0.01 0.00

Particle Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V

2 101.80 -4.64 102.41 -4.22 0.61 0.42 101.47 -8.24 102.13 -7.54 0.66 0.70

4 101.44 0.86 101.22 0.88 -0.23 0.02 101.43 1.52 101.21 1.55 -0.23 0.03

6 98.63 4.11 98.94 4.14 0.31 0.02 98.37 7.07 98.68 7.13 0.31 0.06

7 102.65 3.79 102.66 3.92 0.02 0.13 102.42 6.78 102.42 7.01 0.00 0.23

9 96.60 -4.50 96.70 -4.40 0.10 0.10 96.30 -7.58 96.41 -7.43 0.11 0.16

10 99.53 3.46 99.19 3.52 -0.34 0.07 99.34 6.00 99.00 6.10 -0.34 0.09

11 96.54 -3.54 96.54 -3.66 0.00 -0.12 96.36 -5.96 96.35 -6.16 -0.02 -0.20

14 97.87 2.76 97.63 2.88 -0.24 0.12 97.76 4.71 97.51 4.90 -0.25 0.19

15 98.23 -1.36 98.62 -1.12 0.39 0.25 98.20 -2.34 98.60 -1.92 0.40 0.42

18 102.15 0.50 102.38 0.34 0.23 -0.16 102.15 0.89 102.38 0.61 0.23 -0.28

19 99.59 -9.05 100.06 -9.33 0.47 -0.28 98.35 -15.66 98.74 -16.22 0.38 -0.56

20 100.34 -6.08 100.48 -6.09 0.14 -0.01 99.78 -10.63 99.91 -10.66 0.13 -0.03

21 98.96 -1.04 98.95 -0.93 -0.01 0.11 98.95 -1.79 98.94 -1.60 -0.01 0.19

22 97.90 -4.40 97.92 -4.36 0.02 0.05 97.61 -7.52 97.64 -7.44 0.03 0.08

23 99.15 1.35 99.73 1.49 0.58 0.13 99.12 2.34 99.69 2.59 0.57 0.25

24 105.90 -0.42 106.66 -0.36 0.76 0.06 105.89 -0.78 106.66 -0.68 0.76 0.11

25 102.59 -0.69 102.51 -0.87 -0.08 -0.18 102.58 -1.24 102.50 -1.56 -0.08 -0.32

26 102.14 0.07 102.27 0.19 0.13 0.13 102.14 0.12 102.27 0.34 0.13 0.23

29 97.03 6.65 97.14 6.80 0.11 0.15 96.38 11.24 96.46 11.50 0.08 0.26

30 101.83 -0.50 102.15 -0.41 0.32 0.09 101.83 -0.89 102.14 -0.74 0.32 0.16

34 99.96 4.87 100.23 4.80 0.27 -0.07 99.60 8.48 99.87 8.39 0.28 -0.10

35 104.14 -5.26 104.01 -4.85 -0.13 0.41 103.70 -9.54 103.63 -8.79 -0.06 0.75

38 99.12 -1.10 98.90 -1.04 -0.22 0.07 99.10 -1.91 98.88 -1.79 -0.22 0.12

42 104.88 5.32 105.21 5.24 0.33 -0.08 104.43 9.73 104.77 9.60 0.34 -0.12

43 96.88 8.06 97.23 8.15 0.35 0.10 95.92 13.58 96.25 13.79 0.33 0.21

44 102.20 2.07 102.28 2.14 0.08 0.07 102.13 3.69 102.21 3.81 0.08 0.12

45 101.06 3.18 101.28 3.40 0.22 0.22 100.91 5.60 101.10 6.01 0.20 0.41

46 102.35 1.98 102.52 2.12 0.17 0.14 102.29 3.54 102.45 3.79 0.16 0.25

47 105.58 -2.56 105.08 -2.33 -0.51 0.23 105.48 -4.72 104.99 -4.27 -0.49 0.45

48 101.61 2.14 101.40 2.15 -0.21 0.01 101.54 3.79 101.33 3.80 -0.21 0.01

49 101.24 5.01 101.53 5.19 0.29 0.18 100.85 8.85 101.11 9.19 0.26 0.34

50 105.53 0.47 105.82 0.38 0.29 -0.09 105.52 0.87 105.82 0.71 0.30 -0.17

51 101.78 2.43 101.43 2.65 -0.35 0.22 101.69 4.32 101.33 4.70 -0.37 0.37

56 98.55 -0.39 98.75 -0.39 0.20 0.01 98.55 -0.67 98.75 -0.67 0.20 0.01

59 94.35 -3.10 94.29 -3.10 -0.06 0.00 94.21 -5.11 94.15 -5.10 -0.06 0.01

60 103.33 2.75 103.59 2.76 0.25 0.01 103.21 4.96 103.47 4.99 0.25 0.02

63 102.47 4.41 102.62 4.62 0.15 0.21 102.17 7.88 102.28 8.26 0.12 0.38

68 101.71 -0.37 102.17 -0.78 0.46 -0.42 101.71 -0.65 102.16 -1.40 0.45 -0.75

69 104.24 1.67 104.54 1.61 0.30 -0.06 104.20 3.03 104.50 2.94 0.30 -0.09

70 104.97 -3.77 104.93 -3.56 -0.04 0.21 104.74 -6.91 104.72 -6.51 -0.02 0.39

71 105.06 1.60 104.88 1.57 -0.18 -0.02 105.02 2.93 104.84 2.88 -0.18 -0.05

72 100.14 6.57 99.71 6.75 -0.43 0.19 99.48 11.45 99.02 11.72 -0.46 0.27

73 105.34 -1.02 105.79 -0.98 0.45 0.04 105.32 -1.87 105.77 -1.81 0.45 0.06

74 95.89 1.37 96.25 1.52 0.37 0.15 95.86 2.29 96.22 2.55 0.36 0.26

76 100.16 1.47 100.92 1.51 0.76 0.04 100.13 2.57 100.88 2.65 0.75 0.08

77 96.80 -0.84 96.72 -0.47 -0.08 0.37 96.79 -1.42 96.71 -0.80 -0.07 0.63

78 98.61 -1.83 98.79 -1.74 0.18 0.09 98.56 -3.15 98.74 -3.01 0.19 0.15

79 99.63 -0.72 99.86 -0.47 0.24 0.25 99.62 -1.25 99.86 -0.82 0.24 0.42

80 106.14 -2.08 106.01 -2.24 -0.13 -0.16 106.07 -3.85 105.93 -4.13 -0.14 -0.29

81 101.79 7.53 102.98 7.71 1.19 0.18 100.91 13.34 102.04 13.82 1.13 0.48

85 99.64 -0.74 99.90 -0.85 0.26 -0.11 99.63 -1.29 99.89 -1.49 0.26 -0.20

86 100.77 -6.75 100.73 -6.76 -0.04 -0.01 100.07 -11.84 100.03 -11.86 -0.04 -0.02

90 95.68 10.60 95.65 10.50 -0.03 -0.10 94.04 17.60 94.05 17.43 0.01 -0.18

91 101.11 -2.58 101.22 -2.39 0.11 0.20 101.01 -4.56 101.13 -4.22 0.12 0.34

94 101.04 1.68 101.12 1.63 0.08 -0.05 100.99 2.97 101.08 2.88 0.09 -0.09

96 100.19 2.19 100.11 2.20 -0.07 0.01 100.12 3.82 100.04 3.84 -0.08 0.02

99 100.88 3.79 101.25 3.99 0.37 0.20 100.66 6.66 101.01 7.04 0.35 0.38

Vel-mag

Standard Dev

? Standard Dev

Vel-mag
Table III.2.h. - Laser Velocimeter Results: True Half Power Signal Processing – Statistics and First 100 

selected.

III.29

Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V

Number 6040 6040 6040 6040 6040 6040 6040 6040 6040 6040 6040 6040

Maximum 110.31 13.96 110.62 13.99 1.53 0.56 110.10 25.12 110.39 25.19 1.55 1.02

Minimum 89.23 -15.34 89.39 -15.27 -1.21 -0.64 88.86 -26.45 88.97 -26.39 -1.28 -1.01

Mean 99.94 -0.02 100.07 0.02 0.12 0.05 99.69 -0.04 99.82 0.04 0.12 0.08

2.96 4.05 2.96 4.05 0.28 0.14 2.97 7.06 2.97 7.07 0.28 0.24

Skew 0.00 -0.01 0.01 -0.01 -0.02 -0.06 0.00 -0.01 0.01 -0.01 -0.02 -0.05

Excess 0.05 0.01 0.09 0.01 0.22 0.15 0.04 0.00 0.06 0.01 0.26 0.15

? Mean 0.08 0.10 0.08 0.10 0.01 0.00 0.08 0.18 0.08 0.18 0.01 0.01

0.05 0.07 0.06 0.07 0.01 0.00 0.05 0.13 0.05 0.13 0.01 0.00

Particle Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V

2 101.80 -4.64 102.35 -4.24 0.55 0.41 101.47 -8.24 102.07 -7.56 0.60 0.68

4 101.44 0.86 101.22 0.87 -0.22 0.01 101.43 1.52 101.21 1.54 -0.22 0.01

6 98.63 4.11 98.91 4.12 0.28 0.01 98.37 7.07 98.65 7.11 0.28 0.03

7 102.65 3.79 102.69 3.88 0.05 0.10 102.42 6.78 102.46 6.96 0.04 0.18

9 96.60 -4.50 96.71 -4.41 0.11 0.10 96.30 -7.58 96.42 -7.43 0.12 0.16

10 99.53 3.46 99.29 3.53 -0.23 0.07 99.34 6.00 99.11 6.11 -0.24 0.10

11 96.54 -3.54 96.53 -3.64 -0.02 -0.10 96.36 -5.96 96.33 -6.13 -0.03 -0.17

14 97.87 2.76 97.61 2.87 -0.26 0.11 97.76 4.71 97.49 4.89 -0.27 0.18

15 98.23 -1.36 98.56 -1.13 0.34 0.23 98.20 -2.34 98.54 -1.95 0.34 0.39

18 102.15 0.50 102.40 0.37 0.25 -0.13 102.15 0.89 102.40 0.66 0.25 -0.24

19 99.59 -9.05 100.02 -9.29 0.42 -0.25 98.35 -15.66 98.70 -16.15 0.35 -0.49

20 100.34 -6.08 100.47 -6.07 0.12 0.01 99.78 -10.63 99.90 -10.63 0.12 0.00

21 98.96 -1.04 99.02 -0.89 0.06 0.15 98.95 -1.79 99.01 -1.54 0.06 0.25

22 97.90 -4.40 97.93 -4.36 0.04 0.04 97.61 -7.52 97.65 -7.45 0.04 0.07

23 99.15 1.35 99.66 1.47 0.51 0.12 99.12 2.34 99.63 2.56 0.51 0.22

24 105.90 -0.42 106.53 -0.36 0.64 0.06 105.89 -0.78 106.53 -0.68 0.64 0.11

25 102.59 -0.69 102.55 -0.84 -0.03 -0.15 102.58 -1.24 102.54 -1.50 -0.04 -0.26

26 102.14 0.07 102.26 0.18 0.12 0.11 102.14 0.12 102.26 0.31 0.12 0.20

29 97.03 6.65 97.19 6.76 0.16 0.11 96.38 11.24 96.51 11.45 0.13 0.21

30 101.83 -0.50 102.09 -0.43 0.26 0.07 101.83 -0.89 102.09 -0.77 0.26 0.12

34 99.96 4.87 100.21 4.82 0.25 -0.05 99.60 8.48 99.86 8.42 0.26 -0.06

35 104.14 -5.26 104.06 -4.88 -0.08 0.37 103.70 -9.54 103.68 -8.86 -0.02 0.68

38 99.12 -1.10 98.93 -1.03 -0.19 0.07 99.10 -1.91 98.92 -1.78 -0.18 0.13

42 104.88 5.32 105.24 5.26 0.36 -0.06 104.43 9.73 104.80 9.65 0.37 -0.08

43 96.88 8.06 97.16 8.14 0.28 0.08 95.92 13.58 96.18 13.75 0.26 0.17

44 102.20 2.07 102.25 2.14 0.05 0.07 102.13 3.69 102.18 3.81 0.05 0.12

45 101.06 3.18 101.26 3.38 0.19 0.21 100.91 5.60 101.08 5.97 0.17 0.38

46 102.35 1.98 102.55 2.12 0.20 0.14 102.29 3.54 102.48 3.80 0.19 0.26

47 105.58 -2.56 105.18 -2.37 -0.40 0.20 105.48 -4.72 105.09 -4.34 -0.38 0.38

48 101.61 2.14 101.49 2.14 -0.12 0.01 101.54 3.79 101.42 3.80 -0.12 0.01

49 101.24 5.01 101.51 5.16 0.27 0.14 100.85 8.85 101.10 9.12 0.25 0.27

50 105.53 0.47 105.80 0.42 0.28 -0.05 105.52 0.87 105.80 0.78 0.28 -0.09

51 101.78 2.43 101.52 2.61 -0.26 0.18 101.69 4.32 101.42 4.63 -0.27 0.31

56 98.55 -0.39 98.74 -0.38 0.19 0.01 98.55 -0.67 98.73 -0.65 0.19 0.02

59 94.35 -3.10 94.34 -3.08 -0.01 0.02 94.21 -5.11 94.20 -5.08 -0.01 0.03

60 103.33 2.75 103.57 2.77 0.24 0.01 103.21 4.96 103.45 5.00 0.24 0.03

63 102.47 4.41 102.60 4.61 0.14 0.20 102.17 7.88 102.27 8.25 0.11 0.37

68 101.71 -0.37 102.11 -0.72 0.40 -0.35 101.71 -0.65 102.11 -1.28 0.40 -0.63

69 104.24 1.67 104.50 1.65 0.26 -0.01 104.20 3.03 104.46 3.01 0.26 -0.02

70 104.97 -3.77 104.94 -3.59 -0.03 0.18 104.74 -6.91 104.73 -6.57 -0.01 0.33

71 105.06 1.60 104.92 1.60 -0.14 0.00 105.02 2.93 104.88 2.93 -0.14 0.00

72 100.14 6.57 99.83 6.76 -0.31 0.20 99.48 11.45 99.14 11.76 -0.35 0.30

73 105.34 -1.02 105.74 -0.98 0.41 0.04 105.32 -1.87 105.73 -1.81 0.41 0.06

74 95.89 1.37 96.18 1.50 0.30 0.13 95.86 2.29 96.15 2.51 0.29 0.22

76 100.16 1.47 100.80 1.50 0.64 0.03 100.13 2.57 100.77 2.64 0.64 0.07

77 96.80 -0.84 96.80 -0.48 0.00 0.36 96.79 -1.42 96.79 -0.82 0.01 0.61

78 98.61 -1.83 98.79 -1.77 0.18 0.07 98.56 -3.15 98.74 -3.05 0.19 0.11

79 99.63 -0.72 99.84 -0.51 0.22 0.21 99.62 -1.25 99.84 -0.89 0.22 0.36

80 106.14 -2.08 106.01 -2.26 -0.13 -0.18 106.07 -3.85 105.93 -4.18 -0.14 -0.33

81 101.79 7.53 102.90 7.69 1.11 0.16 100.91 13.34 101.98 13.77 1.07 0.44

85 99.64 -0.74 99.89 -0.80 0.25 -0.06 99.63 -1.29 99.88 -1.40 0.24 -0.10

86 100.77 -6.75 100.75 -6.74 -0.01 0.01 100.07 -11.84 100.06 -11.83 -0.01 0.02

90 95.68 10.60 95.66 10.53 -0.01 -0.07 94.04 17.60 94.05 17.48 0.01 -0.12

91 101.11 -2.58 101.22 -2.41 0.11 0.17 101.01 -4.56 101.13 -4.26 0.12 0.30

94 101.04 1.68 101.12 1.66 0.08 -0.03 100.99 2.97 101.08 2.92 0.08 -0.05

96 100.19 2.19 100.14 2.20 -0.05 0.02 100.12 3.82 100.06 3.85 -0.05 0.03

99 100.88 3.79 101.19 3.97 0.30 0.18 100.66 6.66 100.94 7.00 0.28 0.34

Vel-mag

Standard Dev

? Standard Dev

Vel-mag
Table III.2.i. - Laser Velocimeter Results: Statistics and Errors – Peak, Gaussian and Histogram (3) 

Signal Processing.

III.30

Peak Processing

Measurements Mag-meas Alpha-meas U-select U-meas V-select V-meas

Number 6040 6040 9382 6040 9382 6040

Mean 100.05 0.02 99.72 99.80 -0.01 0.04

Standard Deviation 3.05 4.07 2.98 3.03 6.97 7.09

Errors:

Mean 0.11 0.04 0.10 0.08

Standard Deviation 0.70 0.38 0.70 0.65

Outliers Removed

Number 4264 4264 4264 4264 4264 4264

Mean 99.83 -0.65 99.64 99.73 -1.19 -1.12

Standard Deviation 2.83 2.41 2.77 2.83 4.21 4.19

Errors:

Mean 0.09 0.04 0.09 0.07

Standard Deviation 0.70 0.38 0.70 0.66

Gaussian Processing

Mag-meas Alpha-meas U-select U-meas V-select V-meas

Number 6040 6040 9382 6040 9382 6040

Mean 100.05 0.02 99.72 99.80 -0.01 0.04

Standard Deviation 3.00 4.06 2.98 3.02 6.97 7.07

Errors:

Mean 0.11 0.04 0.11 0.08

Standard Deviation 0.51 0.28 0.51 0.48

Outliers Removed

Number 5909 5909 5909 5909 5909 5909

Mean 100.01 -0.13 99.68 99.78 -0.31 -0.23

Standard Deviation 2.96 3.83 2.93 2.97 6.66 6.67

Errors:

Mean 0.11 0.04 0.11 0.08

Standard Deviation 0.51 0.28 0.51 0.48

Histogram 3 Processing

Mag-meas Alpha-meas U-select U-meas V-select V-meas

Number 7633 7633 9382 7633 9382 7633

Mean 100.06 0.01 99.72 99.81 -0.01 0.02

Standard Deviation 2.99 4.03 2.98 2.99 6.97 7.02

Errors:

Mean 0.11 0.05 0.11 0.08

Standard Deviation 0.31 0.18 0.31 0.31

Outliers Removed

Number 7633 7633 7633 7633 7633 7633

Mean 100.06 0.01 99.70 99.81 -0.06 0.02

Standard Deviation 2.98 4.03 2.98 3.00 7.01 7.02

Errors:

Mean 0.11 0.05 0.11 0.08

Standard Deviation 0.31 0.18 0.31 0.31
Table III.2.i. (cont'd) - Laser Velocimeter Results: Statistics and Errors – Histogram (5), Half Power, and 

True Half Power Signal Processing.

III.31

Histogram 5 Processing

Mag-meas Alpha-meas U-select U-meas V-select V-meas

Number 7633 7633 9382 7633 9382 7633

Mean 100.07 0.01 99.72 99.82 -0.01 0.02

Standard Deviation 3.00 4.03 2.98 3.01 6.97 7.03

Errors:

Mean 0.12 0.05 0.12 0.08

Standard Deviation 0.40 0.23 0.41 0.40

Outliers Removed

Number 7633 7633 7633 7633 7633 7633

Mean 100.07 0.01 99.70 99.82 -0.06 0.02

Standard Deviation 2.99 4.03 2.98 3.01 7.01 7.03

Errors:

Mean 0.12 0.05 0.12 0.08

Standard Deviation 0.40 0.23 0.41 0.40

Half Power Processing

Mag-meas Alpha-meas U-select U-meas V-select V-meas

Number 6040 6040 9382 6040 9382 6040

Mean 100.07 0.02 99.72 99.82 -0.01 0.04

Standard Deviation 2.97 4.06 2.98 2.98 6.97 7.07

Errors:

Mean 0.12 0.05 0.12 0.08

Standard Deviation 0.33 0.16 0.33 0.28

Outliers Removed

Number 6040 6040 6040 6040 6040 6040

Mean 100.07 0.02 99.69 99.82 -0.04 0.04

Standard Deviation 2.96 4.06 2.97 2.98 7.06 7.07

Errors:

Mean 0.12 0.05 0.12 0.08

Standard Deviation 0.33 0.16 0.33 0.28

True Half Power Processing

Mag-meas Alpha-meas U-select U-meas V-select V-meas

Number 6040 6040 9382 6040 6040 9382

Mean 100.07 0.02 99.72 99.82 -0.01 0.04

Standard Deviation 2.96 4.05 2.98 2.97 6.97 7.07

Errors:

Mean 0.12 0.05 0.12 0.08

Standard Deviation 0.28 0.14 0.28 0.24

Outliers Removed

Number 6040 6040 6040 6040 6040 6040

Mean 100.07 0.02 99.69 99.82 -0.04 0.04

Standard Deviation 2.96 4.05 2.97 2.97 7.06 7.07

Errors:

Mean 0.12 0.05 0.12 0.08

Standard Deviation 0.28 0.14 0.28 0.24
Table III.3. - Laser Velocimeter Results: Comparison of signal processing results, with and without 

outliers.

III.32

Theoretical Distribution

Velocity Magnitude Vertical Flow Angle (alpha)

Mean Sigma Mean Sigma

(m/s) (m/s) (degree) (degree)

100.00 3.00 0.00 4.00

Distribution of particles randomly selected from the Theoretical Distributions

Number of Velocity Magnitude: Vertical Flow Angle (alpha) U-component V-component

Particles Mean Sigma Mean Sigma Mean Sigma Mean Sigma

(m/s) (m/s) (degree) (degree) (m/s) (m/s) (m/s) (m/s)

10000 99.98 2.97 0.01 4.02 99.74 2.98 0.02 7.00

Distribution of particles whose signals trigger the oscilloscope based on high-trigger levels with pretriggering

Number of Velocity Magnitude: Vertical Flow Angle (alpha) U-component V-component

Particles Mean Sigma Mean Sigma Mean Sigma Mean Sigma

(m/s) (m/s) (degree) (degree) (m/s) (m/s) (m/s) (m/s)

9382 99.94 2.97 -0.02 4.05 99.72 2.98 -0.01 6.97

Measurement statistics of the processed signals

Number of Velocity Magnitude Vertical Flow Angle (alpha)

Particles Mean Error in Mean Sigma Error in Sigma Mean Error in Mean Sigma Error in Sigma

(m/s) (m/s) (m/s) (degree) (degree) (degree) (degree) (degree)

Peak 6040 100.05 0.11 3.05 0.70 0.02 0.04 4.07 0.38

Gaussian 6040 100.05 0.11 3.00 0.51 0.02 0.04 4.06 0.28

Histogram (3) 7633 100.06 0.11 2.99 0.31 0.01 0.05 4.03 0.18

Histogram (5) 7633 100.07 0.12 3.00 0.40 0.01 0.05 4.03 0.23

Half Power 6040 100.07 0.12 2.97 0.33 0.02 0.05 4.06 0.16

Half Power True 6040 100.07 0.12 2.96 0.28 0.02 0.05 4.05 0.14

Number of U-component V-component

Particles Mean Error in Mean Sigma Error in Sigma Mean Error in Mean Sigma Error in Sigma

(m/s) (m/s) (m/s) (m/s) (m/s) (m/s) (m/s) (m/s)

Peak 6040 99.80 0.10 3.03 0.70 0.04 0.08 7.09 0.65

Gaussian 6040 99.80 0.11 3.02 0.51 0.04 0.08 7.07 0.48

Histogram (3) 7633 99.81 0.11 2.99 0.31 0.02 0.08 7.02 0.31

Histogram (5) 7633 99.82 0.12 3.01 0.41 0.02 0.08 7.03 0.40

Half Power 6040 99.82 0.12 2.98 0.33 0.04 0.08 7.07 0.28

Half Power True 6040 99.82 0.12 2.97 0.28 0.04 0.08 7.07 0.24

Measurement statistics of the processed signals – outliers removed

Number of Velocity Magnitude Vertical Flow Angle (alpha)

Particles Mean Error in Mean Sigma Error in Sigma Mean Error in Mean Sigma Error in Sigma

(m/s) (m/s) (m/s) (m/s) (degree) (degree) (degree) (degree)

Peak 4264 99.83 0.09 2.82 0.70 -0.65 0.04 2.41 0.38

Gaussian 5909 100.01 0.11 2.96 0.51 -0.13 0.04 3.83 0.28

Histogram (3) 7633 100.06 0.11 2.99 0.31 0.01 0.05 4.03 0.18

Histogram (5) 7633 100.07 0.12 3.00 0.40 0.01 0.05 4.03 0.23

Half Power 6040 100.07 0.12 2.97 0.33 0.02 0.05 4.06 0.16

Half Power True 6040 100.07 0.12 2.96 0.28 0.02 0.05 4.05 0.14

Number of U-component V-component

Particles Mean Error in Mean Sigma Error in Sigma Mean Error in Mean Sigma Error in Sigma

(m/s) (m/s) (m/s) (m/s) (m/s) (m/s) (m/s) (m/s)

Peak 4264 99.73 0.09 2.80 0.70 -1.12 0.07 4.19 0.66

Gaussian 5909 99.78 0.11 2.97 0.51 -0.23 0.08 6.67 0.48

Histogram (3) 7633 99.81 0.11 2.99 0.31 0.02 0.08 7.02 0.31

Histogram (5) 7633 99.82 0.12 3.01 0.41 0.02 0.08 7.03 0.40

Half Power 6040 99.82 0.12 2.98 0.33 0.04 0.08 7.07 0.28

Half Power True 6040 99.82 0.12 2.97 0.28 0.04 0.08 7.07 0.24
Figure III.1.- Upgraded laser velocimeter optical system installed in BART.

III.33
Figure III.2.- Particle injection distribution in the vertical and on-axis plane based on uniform statistics over 

a window defined by ±150-percent of the beam waist radius (radius defined by the 1/e2 power locus).

III.34

0.01

0.5

2

10

30

50

70

90

98

99.5

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1 .5 2.0

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1 .5 2.0

0

100

200

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500

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700

800

Counts

Enterenceheight, radius

CumulativeCounts

0.01

0.5

2

10

30

50

70

90

98

99.5

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

0

100

200

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800

Counts

Exit height, radius

CumulativeCounts

0.01

0.5

2

10

30

50

70

90

98

99.5

-2.0 -1 .5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

-2.0 -1 .5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

0

100

200

300

400

500

600

700

800

Counts

On axis location, on-axis radius

Cumulative Counts
Figure III.3.- Velocity and flow angle distributions obtained by Gaussian random number selection based 

on the overlaid Gaussian distributions: Velocity magnitude = 100.0 m/s with a standard deviation of 

3.0 m/s, and a vertical flow angle = 0.0 degrees with a standard deviation of 4.0 degrees, total number of 

particles = 10,000.

III.35

0.01

0.5

2

10

30

50

70

90

98

99.5

88 90 92 94 96 98 100 102 104 106 108 110 112

88 90 92 94 96 98 100 102 104 106 108 110 112

0

200

400

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800

1000

1200

1400

C ount s

Velocitymagnitude,m/s

Cu mulat ive Co unts

0.01

0.5

2

10

30

50

70

90

98

99.5

-14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14

-14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14

0

200

400

600

800

1000

1200

1400

C ount s

Flow angle, degrees

Cu mulat ive Co unts

0.01

0.5

2

10

30

50

70

90

98

99.5

88 90 92 94 96 98 100 102 104 106 108 110 112

88 90 92 94 96 98 100 102 104 106 108 110 112

0

200

400

600

800

1000

1200

1400

C ou n ts

U-component velocity, m/s

C umulative C o un ts

0.01

0.5

2

10

30

50

70

90

98

99.5

-25 -20 -15 -10 -5 0 5 10 15 20 25

-25 -20 -15 -10 -5 0 5 10 15 20 25

0

200

400

600

800

1000

1200

1400

C ou n ts

V-component velocity, m/s

C umulative C o un ts
Figure III.4.- Velocity and flow angle distributions from particles with sufficient signal strength to trigger the 

oscilloscope, total number of particles = 9382.

III.36

0.01

0.5

2

10

30

50

70

90

98

99.5

88 90 92 94 96 98 100 102 104 106 108 110 112

88 90 92 94 96 98 100 102 104 106 108 110 112

0

200

400

600

800

1000

1200

1400

C ount s

Velocitymagnitude,m/s

Cu mulative Co unts

0.01

0.5

2

10

30

50

70

90

98

99.5

-14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14

-14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14

0

200

400

600

800

1000

1200

1400

C ount s

Flow angle, degrees

Cu mulative Co unts

0.01

0.5

2

10

30

50

70

90

98

99.5

88 90 92 94 96 98 100 102 104 106 108 110 112

88 90 92 94 96 98 100 102 104 106 108 110 112

0

200

400

600

800

1000

1200

1400

C ou n ts

U-component velocity, m/s

C umulative C o un ts

0.01

0.5

2

10

30

50

70

90

98

99.5

-25 -20 -15 -10 -5 0 5 10 15 20 25

-25 -20 -15 -10 -5 0 5 10 15 20 25

0

200

400

600

800

1000

1200

1400

C ou n ts

V-component velocity, m/s

C umulative C o un ts

Ideal Triggered Ideal Triggered
Figure III.5.- Velocity and flow angle distributions from particles that yielded velocity measurements based 

on the particle velocity determined by the peak signal frequency, total number of particles = 4264.

III.37

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

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800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: (particle), m/s Flow angle: (particle), degrees

-12 -8 -4 0 4 8 12

-14 -10 -6 -2 2 6 10 14

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: (Measured), m/s Flow angle: (Measured), degrees

-12 -8 -4 0 4 8 12

-14 -10 -6 -2 2 6 10 14

0.01

0.5

10

30

50

70

90

98

99.5

200

400

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800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: Error, m/s Flow angle: Error, degrees

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

Ideal Selected Ideal Selected

Ideal Selected Ideal Selected

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5
Figure III.6.- Velocity and flow angle distributions from particles that yielded velocity measurements based 

on the particle velocity determined by a Gaussian fit of the peak signal frequency, total number of 

particles = 5909.

III.38

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: (particle), m/s Flow angle: (particle), degrees

-12 -8 -4 0 4 8 12

-14 -10 -6 -2 2 6 10 14

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: (Measured), m/s Flow angle: (Measured), degrees

-12 -8 -4 0 4 8 12

-14 -10 -6 -2 2 6 10 14

0.01

0.5

10

30

50

70

90

98

99.5

200

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1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: Error, m/s Flow angle: Error, degrees

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

Ideal Selected Ideal Selected

Ideal Selected Ideal Selected

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5
Figure III.7.- Velocity and flow angle distributions from particles that yielded velocity measurements based 

on the particle velocity determined by 3-bin histogram average of the peak signal frequency, total number 

of particles = 7633.

III.39

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

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1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: (particle), m/s Flow angle: (particle), degrees

-12 -8 -4 0 4 8 12

-14 -10 -6 -2 2 6 10 14

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: (Measured), m/s Flow angle: (Measured), degrees

-12 -8 -4 0 4 8 12

-14 -10 -6 -2 2 6 10 14

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: Error, m/s Flow angle: Error, degrees

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

Ideal Selected Ideal Selected

Ideal Selected Ideal Selected

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5
Figure III.8.-Velocity and flow angle distributions from particles that yielded velocity measurements based 

on the particle velocity determined by 5-bin histogram average of the peak signal frequency, total number 

of particles = 7633.

III.40

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: (particle), m/s Flow angle: (particle), degrees

-12 -8 -4 0 4 8 12

-14 -10 -6 -2 2 6 10 14

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: (Measured), m/s Flow angle: (Measured), degrees

-12 -8 -4 0 4 8 12

-14 -10 -6 -2 2 6 10 14

0.01

0.5

10

30

50

70

90

98

99.5

200

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1000

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1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: Error, m/s Flow angle: Error, degrees

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

Ideal Selected Ideal Selected

Ideal Selected Ideal Selected

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5
Figure III.9.- Velocity and flow angle distributions from particles that yielded velocity measurements based 

on the particle velocity determined by half power average of the peak signal frequency, total number of 

particles = 6040.

III.41

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

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1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

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1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: (particle), m/s Flow angle: (particle), degrees

-12 -8 -4 0 4 8 12

-14 -10 -6 -2 2 6 10 14

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: (Measured), m/s Flow angle: (Measured), degrees

-12 -8 -4 0 4 8 12

-14 -10 -6 -2 2 6 10 14

0.01

0.5

10

30

50

70

90

98

99.5

200

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1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

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98

99.5

200

400

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800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: Error, m/s Flow angle: Error, degrees

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

Ideal Selected Ideal Selected

Ideal Selected Ideal Selected

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5
Figure III.10.- Velocity and flow angle distributions from particles that yielded velocity measurements 

based on the particle velocity determined by interpolated half power average of the peak signal frequency, 

total number of particles = 6040.

III.42

0

0

0

0

0

0

0

0

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

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98

99.5

200

400

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1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

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98

99.5

200

400

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1000

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1400

0

Cumulative Counts Counts

Velocity magnitude: (particle), m/s Flow angle: (particle), degrees

-12 -8 -4 0 4 8 12

-14 -10 -6 -2 2 6 10 14

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

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90

98

99.5

200

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0

Cumulative Counts Counts

0.01

0.5

10

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98

99.5

200

400

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800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: (Measured), m/s Flow angle: (Measured), degrees

-12 -8 -4 0 4 8 12

-14 -10 -6 -2 2 6 10 14

0.01

0.5

10

30

50

70

90

98

99.5

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1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

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90

98

99.5

200

400

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800

1000

1200

1400

0

Cumulative Counts Counts

Velocity magnitude: Error, m/s Flow angle: Error, degrees

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

Ideal Selected Ideal Selected

Ideal Selected Ideal Selected

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5
Figure III.11.- U- and V-component distributions from particles that yielded velocity measurements based 

on the particle velocity determined by the peak signal frequency, total number of particles = 4264.

III.43

Ideal Selected Ideal Selected

Ideal Selected Ideal Selected

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

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0

Cumulative Counts Counts

0.01

0.5

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98

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Cumulative Counts Counts

U-component velocity: (particle), m/s V-component velocity: (particle), m/s

-20 -10 0 10 20

-25 -15 -5 5 15 25

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

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98

99.5

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Cumulative Counts Counts

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Cumulative Counts Counts

U-component velocity: (Measured), m/s V-component velocity: (Measured), m/s

0.01

0.5

10

30

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98

99.5

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Cumulative Counts Counts

0.01

0.5

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0

Cumulative Counts Counts

U-component velocity: Error, m/s V-component: Error, m/s

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-20 -10 0 10 20

-25 -15 -5 5 15 25

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5
Figure III.12.- U- and V-component distributions from particles that yielded velocity measurements based 

on the particle velocity determined by a Gaussian fit of the peak signal frequency, total number of 

particles = 6040.

III.44

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

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0

Cumulative Counts Counts

0.01

0.5

10

30

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98

99.5

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1400

0

Cumulative Counts Counts

U-component velocity: (particle), m/s V-component velocity: (particle), m/s

-20 -10 0 10 20

-25 -15 -5 5 15 25

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

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98

99.5

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0

Cumulative Counts Counts

0.01

0.5

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98

99.5

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0

Cumulative Counts Counts

U-component velocity: (Measured), m/s V-component velocity: (Measured), m/s

0.01

0.5

10

30

50

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90

98

99.5

200

400

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1400

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Cumulative Counts Counts

0.01

0.5

10

30

50

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90

98

99.5

200

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1000

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1400

0

Cumulative Counts Counts

U-component velocity: Error, m/s V-component: Error, m/s

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-20 -10 0 10 20

-25 -15 -5 5 15 25

Ideal Selected Ideal Selected

Ideal Selected Ideal Selected

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5
Figure III.13.- U- and V-component distributions from particles that yielded velocity measurements based 

on the particle velocity determined by 3-bin histogram average of the peak signal frequency, total number 

of particles = 7633.

III.45

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

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1000

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1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

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1000

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1400

0

Cumulative Counts Counts

U-component velocity: (particle), m/s V-component velocity: (particle), m/s

-20 -10 0 10 20

-25 -15 -5 5 15 25

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

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1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

U-component velocity: (Measured), m/s V-component velocity: (Measured), m/s

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

U-component velocity: Error, m/s V-component: Error, m/s

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-20 -10 0 10 20

-25 -15 -5 5 15 25

Ideal Selected Ideal Selected

Ideal Selected Ideal Selected

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5
Figure III.14.- U- and V-component distributions from particles that yielded velocity measurements based 

on the particle velocity determined by 5-bin histogram average of the peak signal frequency, total number 

of particles = 7633.

III.46

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

U-component velocity: (particle), m/s V-component velocity: (particle), m/s

-20 -10 0 10 20

-25 -15 -5 5 15 25

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

U-component velocity: (Measured), m/s V-component velocity: (Measured), m/s

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

U-component velocity: Error, m/s V-component: Error, m/s

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-20 -10 0 10 20

-25 -15 -5 5 15 25

Ideal Selected Ideal Selected

Ideal Selected Ideal Selected

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5
Figure III.15.- U- and V-component distributions from particles that yielded velocity measurements based 

on the particle velocity determined by half power average of the peak signal frequency, total number of 

particles = 6040.

III.47

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

U-component velocity: (particle), m/s V-component velocity: (particle), m/s

-20 -10 0 10 20

-25 -15 -5 5 15 25

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

U-component velocity: (Measured), m/s V-component velocity: (Measured), m/s

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

U-component velocity: Error, m/s V-component: Error, m/s

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-20 -10 0 10 20

-25 -15 -5 5 15 25

Ideal Selected Ideal Selected

Ideal Selected Ideal Selected

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5
Figure III.16.- U- and V-component distributions from particles that yielded velocity measurements based 

on the particle velocity determined by interpolated half power average of the peak signal frequency, total 

number of particles = 6040.

III.48

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

U-component velocity: (particle), m/s V-component velocity: (particle), m/s

-20 -10 0 10 20

-25 -15 -5 5 15 25

90 94 98 102 106 110

88 92 96 100 104 108 112

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

U-component velocity: (Measured), m/s V-component velocity: (Measured), m/s

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

0.01

0.5

10

30

50

70

90

98

99.5

200

400

600

800

1000

1200

1400

0

Cumulative Counts Counts

U-component velocity: Error, m/s V-component: Error, m/s

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-20 -10 0 10 20

-25 -15 -5 5 15 25

Ideal Selected Ideal Selected

Ideal Selected Ideal Selected

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

-1.5 -1.0 -0.5 0 0.5 1.0 1.5
Figure III.17.- Statistical convergence of the mean velocity magnitude based on the six signal processing 

schemes. 

III.49

Input statistics (10,000)

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

98.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

Mean velocity magnitude, m/s

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

98.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

Mean velocity magnitude, m/s

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

98.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

Mean velocity magnitude, m/s

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

98.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

Mean velocity magnitude, m/s

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

98.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

Meanvelocity magnitude, m/s

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

98.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

Meanvelocity magnitude, m/s

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.18.- Statistical convergence of the velocity magnitude standard deviation based on the six 

signal processing schemes.

III.50

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

Velocity magnitude standard deviation, m/s

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

Velocity magnitude standard deviation, m/s

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

Velocity magnitude standard deviation, m/s

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

Velocity magnitude standard deviation, m/s

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

Velocity magnitude standard deviation, m/s

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

Velocity magnitude standard deviation, m/s

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.19.- Statistical convergence of the velocity magnitude skew based on the six signal processing 

schemes.

III.51

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

Velocity magnitude skew

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

Velocity magnitude skew

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

Velocity magnitude skew

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

Mean velocity skew

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

Velocity magnitudeskew

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

Velocity magnitudeskew

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.20.- Statistical convergence of the velocity magnitude excess based on the six signal 

processing schemes.

III.52

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

Velocity magnitudeexcess

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

Velocity magnitudeexcess

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

Velocity magnitudeexcess

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

Velocity magnitudeexcess

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

Velocity magnitude excess

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

Velocity magnitude excess

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.21.- Statistical convergence of the mean flow angle based on the six signal processing 

schemes.

III.53

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Mean flow angle, degrees

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 4500 5000

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Mean flow angle, degrees

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Mean flow angle, degrees

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Mean flow angle, degrees

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Meanflow angle, degrees

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Meanflow angle, degrees

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.22.- Statistical convergence of the flow angle standard deviation based on the six signal 

processing schemes.

III.54

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Flow anglestandard deviation, degrees

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Flow anglestandard deviation, degrees

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Flow anglestandard deviation, degrees

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Flow anglestandard deviation, degrees

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Flow angle standard deviation, degrees

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Flow angle standard deviation, degrees

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.23.- Statistical convergence of the flow angle skew based on the six signal processing 

schemes.

III.55

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

Flow angle skew

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

Flow angle skew

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

Flowangle skew

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

Flowangle skew

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

Flowangle skew

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

Flowangle skew

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.24.- Statistical convergence of the flow angle excess based on the six signal processing 

schemes.

III.56

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.5

-1.4

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

Flow angle excess

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.5

-1.4

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

Flow angle excess

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.5

-1.4

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

Flow angle excess

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.5

-1.4

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

Flow angle excess

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.5

-1.4

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

Flow angle excess

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.5

-1.4

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

Flow angle excess

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.25.- Statistical convergence of the mean U-component velocity based on the six signal 

processing schemes.

III.57

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

97.0

97.5

98.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

U-component velocity mean, m/s

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

97.0

97.5

98.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

U-component velocity mean, m/s

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

97.0

97.5

98.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

U-component velocity mean, m/s

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

97.0

97.5

98.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

U-component velocity mean, m/s

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

97.0

97.5

98.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

U-component velocity mean, m/s

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

97.0

97.5

98.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

U-component velocity mean, m/s

Total number in the ensemble

True Half Power processing
Figure III.26.- Statistical convergence of the U-component standard deviation based on the six signal 

processing schemes.

III.58

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

U-component velocity standard deviation, m/s

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

U-component velocity standard deviation, m/s

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

U-component velocity standarddeviation, m/s

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

U-component velocity standarddeviation, m/s

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

U-component velocity standarddeviation, m/s

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

U-component velocity standarddeviation, m/s

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.27.- Statistical convergence of the U-component skew based on the six signal processing 

schemes.

III.59

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

U-component skew

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

U-component skew

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

U-component skew

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

U-component skew

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

U-component skew

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.50

-0.45

-0.40

-0.35

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

U-component skew

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.28.- Statistical convergence of the U-component excess based on the six signal processing 

schemes.

III.60

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

U-component excess

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

U-component excess

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

U-component excess

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

U-component excess

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

U-component excess

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

U-component excess

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.29.- Statistical convergence of the mean V-component velocity based on the six signal 

processing schemes.

III.61

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

V-component velocity mean, m/s

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

V-component velocity mean, m/s

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

V-component velocity mean, m/s

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

V-component velocity mean, m/s

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

V-component velocity mean, m/s

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

V-component velocity mean, m/s

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.30.- Statistical convergence of the V-component standard deviation based on the six signal 

processing schemes.

III.62

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

V-component velocity standarddeviation,m/s

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

V-component velocity standarddeviation,m/s

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

V-component velocity standard deviation, m/s

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

V-component velocity standard deviation, m/s

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

V-component velocity standard deviation, m/s

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

V-component velocity standard deviation, m/s

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.31.- Statistical convergence of the V-component skew based on the six signal processing 

schemes.

III.63

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

V-component skew

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

V-component skew

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

V-component skew

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

V-componentskew

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

V-component skew

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

V-componentskew

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.32.- Statistical convergence of the V-component excess based on the six signal processing 

schemes.

III.64

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.5

-1.4

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

V-componentexcess

Total number in the ensemble

Peak processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.5

-1.4

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

V-componentexcess

Total number in the ensemble

Gaussian processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.5

-1.4

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

V-component excess

Total number in the ensemble

Histogram 3 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.5

-1.4

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

V-component excess

Total number in the ensemble

Histogram 5 processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.5

-1.4

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

V-component excess

Total number in the ensemble

Half Power processing

 Particle

 Measurement

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

-1.5

-1.4

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

V-component excess

Total number in the ensemble

True Half Power processing

 Particle

 Measurement
Figure III.33.- Statistical convergence of the velocity magnitude measurement errors based on the six 

signal processing schemes.

III.65

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 Mean velocity magnitude

 Velocity magnitude standard deviation

Measurementerror, m/s

Total number in the ensemble

Peak processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 Mean velocity magnitude

 Velocity magnitude standard deviation

Measurementerror, m/s

Total number in the ensemble

Gaussian processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 Mean velocity magnitude

 Velocity magnitude standard deviation

Measurementerror, m/s

Total number in the ensemble

Histogram 3 processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 Mean velocity magnitude

 Velocity magnitude standard deviation

Measurementerror, m/s

Total number in the ensemble

Histogram 5 processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 Mean velocity magnitude

 Velocity magnitude standard deviation

Measurementerror, m/s

Total number in the ensemble

Half Power processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 Mean velocity magnitude

 Velocity magnitude standard deviation

Measurementerror, m/s

Total number in the ensemble

Half Power True processing
Figure III.34.- Statistical convergence of the flow angle measurement errors based on the six signal 

processing schemes.

III.66

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

 Mean flow angle

 Flow angle standard deviation

Measurement error, degrees

Total number in the ensemble

Peak processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

 Mean flow angle

 Flow angle standard deviation

Measurement error, degrees

Total number in the ensemble

Gaussian processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

 Mean flow angle

 Flow angle standard deviation

Measurementerror, degrees

Total number in the ensemble

Histogram 3 processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

 Mean flow angle

 Flow angle standard deviation

Measurementerror, degrees

Total number in the ensemble

Histogram 5 processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

 Mean flow angle

 Flow angle standard deviation

Measurement error, degrees

Total number in the ensemble

Half Power processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

 Mean flow angle

 Flow angle standard deviation

Measurement error, degrees

Total number in the ensemble

Half Power True processing
Figure III.35.- Statistical convergence of the U-component measurement errors based on the six signal 

processing schemes.

III.67

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 U-component velocity mean

 U-component velocity standard deviation

Measurement error, m/s

Total number in the ensemble

Peak processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 U-component velocity mean

 U-component velocity standard deviation

Measurement error, m/s

Total number in the ensemble

Gaussian processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 U-component velocity mean

 U-component velocity standard deviation

Measurement error, m/s

Total number in the ensemble

Histogram 3 processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 U-component velocity mean

 U-component velocity standard deviation

Measurement error, m/s

Total number in the ensemble

Histogram 5 processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 U-component velocity mean

 U-component velocity standard deviation

Measurement error, m/s

Total number in the ensemble

Half Power processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 U-component velocity mean

 U-component velocity standard deviation

Measurement error, m/s

Total number in the ensemble

True Half Power processing
Figure III.36.- Statistical convergence of the V-component measurement errors based on the six signal 

processing schemes.

III.68

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 V-component velocity mean

 V-component velocity standard deviation Measurement error, m/s

Total number in the ensemble

Peak processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 V-component velocity mean

 V-component velocity standard deviation

Measurement error, m/s

Total number in the ensemble

Gaussian processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 V-component velocity mean

 V-component velocity standard deviation

Measurement error, m/s

Total number in the ensemble

Histogram 3 processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 V-component velocity mean

 V-component velocity standard deviation

Measurement error, m/s

Total number in the ensemble

Histogram 5 processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 V-component velocity mean

 V-component velocity standard deviation

Measurement error, m/s

Total number in the ensemble

Half Power processing

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

 V-component velocity mean

 V-component velocity standard deviation

Measurement error, m/s

Total number in the ensemble

Ture Half Power processing
Laser Velocimeter Data Acquisition System

Implementation

Now that the Monte Carlo simulation has demonstrated that the proposed system would 

have the ability to satisfy the required measurement accuracy, and that signal processing 

could be performed within the time constraints needed for real time processing, the data 

acquisition system was constructed. It consisted of two parts: hardware to capture the 

signal bursts, acquire auxiliary data, temporarily store the data, and then transfer it to the 

computers; and the software necessary to control the data acquisition process and conduct 

the signal/data processing of the captured signal bursts. To minimize the risk in a 

production environment, the data acquisition and signal/data processing functions were 

separated by using two computers connected by a 1.0 Gb/s data link. The system would be 

configured such that the data acquisition computer would have total control of the process 

including control of the signal/data processing computer. The signal/data processing would 

be autonomous with the data acquisition program responsible for transferring the data and 

the corresponding control file to the signal/data processing computer. Once the transfers 

are completed, the signal/data processing program will recognize the update of the control 

file and begin processing the new data.

Hardware

The upgraded laser velocimeter data acquisition system employs a dual channel, highspeed digitizer, along with a general purpose data acquisition system and a general purpose 

counter/timer mounted in a PXI chassis (Compact PCI standard) as the data acquisition 

hardware. Two networked PC-server class computers are used in support of this 

hardware. One computer provides the control, setup and arming of the digitizers, and data 

transfer from the digitizers to permanent storage. The second computer provides the 

signal/data processing capabilities in an automated manner to provide real-time statistics 

and distributions of the U- and V-component velocity measurement ensembles, along with 

the velocity magnitude and flow angle results computed signal burst-by-signal burst from 

the component measurements. These results are displayed in real time as feedback to the 

user to provide insight into data quality and help guide the development of the test matrix. 

The detailed specifications of the acquisition hardware follow.

PXI Data Acquisition System Specifications

The PXI-hosted data acquisition system was constructed using components manufactured 

by National Instruments, Inc. (NI). The system consists of the following subsystems:

NI PXI-1042 PXI Chassis

This 8-slot, 3U size form factor, rack-mountable chassis provides a high-output power 

supply with cooling, and a signal interconnection backplane to house and interface the 

various data acquisition modules together as a complete system. The chassis houses 

IV.1
modular 3U-sized, Eurocard standard compliant, printed circuit boards adhering to the 

compact PCI specifications. The backplane provides standardized interfacing and 

synchronization signals to allow communication and control between the various modules 

inserted in the chassis. The unit operates as an extension of the host computer's PCI bus.

NI PXI-PCI8331 Interface

This module provides the control and data transfer interface to the host computer. The 

module is composed of two components – a plug-in board that resides in the PXI chassis, 

and a PCI plug-in board residing in the host computer. The two boards are interconnected 

via a system bus cable. This interface provides MXI-4 link information transfer rates of up 

to 132 Mbytes/s (peak) and 78 Mbytes/s (sustained) 

NI PXI-5152 High-Speed Digitizers

This 8-bit digitizer is the key component in the data acquisition process as it 

simultaneously digitizes the signal bursts from both the U- and V-components of the laser 

velocimeter. It was selected because its bandwidth and sample rate were sufficient to 

obtain five samples per cycle from the highest signal frequency obtainable from the 

photomultipliers. These capabilities also allow direct measurement of the Bragg shifted 

signal frequency, thus eliminating the noise imposed by a double-balanced mixer commonly 

used in laser velocimetry to bring the signal frequencies within range of the current signal 

processors. The significant specifications of the two-channel, high-speed digitizer are:

• Sample Rates: 2 GS/s single channel, 1 GS/s simultaneous two channel;

• 8-bit resolution;

• 100 mVpp to 10 Vpp analog signal input range;

• 300 MHz analog signal bandwidth;

• 256 Mbyte/channel on-board memory (512 Mbyte total);

• Programmable sample rate, record length, and amplitude range;

• Edge, window, and external triggering capabilities;

• Programmable pretrigger and post-trigger capabilities; and,

• Time Stamp capabilities for each digitized trace (interarrival times).

NI PXI-6120 Multifunction Data Acquisition Module

This module provides the capability to sample analog or digital signals produced by 

peripheral measurement devices that must be captured each time a laser velocimeter signal 

burst is acquired (conditional sampling). Additionally this module contains analog and 

digital output channels that are available for controlling external devices, and 

counter/timers that can be used to time external events. The significant specifications of 

the multifunction data acquisition module are:

IV.2
• 4 Analog input channels – simultaneously sampled

 ±200 mVpp to ±12 Vpp Analog signal input range

 16-bit Digitizer resolution

 800 kS/s Sample rate;

• 2 Analog output channels

 ±10 V Output voltage range

 8-bit Digital output;

• 2 Counter/timers

 24-bit;

• Analog or digital triggering capability.

NI PXI-6602 Counter/Timer Module

This module provides the capability to asynchronously record rotor azimuth position by 

counting the pulses from the shaft encoder and storing the current value when the trigger 

signifying the capture of a signal burst occurs. The counter continues counting the 

encoder pulses until reset by the one-per-rev pulse from the encoder. It is recommended 

that all shaft encoders provide at least 1024 counts per shaft revolution for maximum 

azimuth measurement accuracy. The module can also be configured to simulate the 

functionality of the azimuth encoder for system verification. The significant specifications 

for the counter/timer are:

• 8-channel, 32-bit up/down counter/timer;

• 32 digital I/O lines (5 V TTL/CMOS);

• 80 MHz maximum source frequency.

Computer Specifications

Two identical PC-server class computers are networked together with 1.0 Gb/s 

communication capability to provide data acquisition hardware control and data transfer 

(data acquisition computer), and signal/data processing/display functions (signal processing 

computer). The computers use the Microsoft Windows 7, 64-bit Professional operating 

system. The data acquisition computer is equipped with LabVIEW version 11 and the 

LabVIEW compiler. The signal/data processing computer is equipped with the Intel 

Fortran 90, version 11 compiler with both 32-bit and 64-bit versions. The GrWin graphics 

libraries, in both 32-bit and 64-bit versions are available. Both computers have software to 

preform diagnostics, data manipulation, code development along with plotting and display 

software used for in situ tasks in code development, report writing, and data interrogation 

and plotting. The computers consist of the following components:

• Rack mount system case;

• SuperMicro X7DAL-E Server Motherboard with 2 Socket-J Processor Sockets, 

24-Gbyte max memory support;

IV.3
• Intel Xeon Quad Core Processor with 2.33 GHz clock speed, 1.33 GHz front side 

bus, 12 Mbyte L2 cache;

• 8 Gbyte RAM;

• 6 open 5.25-inch bays that include:

 1 RAID 0 drive using two 1.0 Tbyte SATA drives, 7200 rpm;

 1 1.0 Tbyte SATA drive, 7200 rpm – hot swappable for data backup/transfer;

 1 500 Mbyte ATA drive, 7200 rpm – hot swappable for data backup/transfer;

 1 DVD player/recorder;

• 2 in-chassis 3.5-inch bays that include:

 1 750 Mbyte SATA drive, 7200 rpm – operating system, programs, etc.

• Sapphire Radeon HD 3870 Graphics Card with on-board 512 Mbyte memory and 

775 MHz graphics processor;

• 2 1.0 Gb network ports;

• 620 W Power Supply;

• 24-inch LCD display with 1920x1200 pixel resolution.

Peripheral Components

The two peripheral components that are used during laser velocimetry investigations and 

system testing are the high-speed digital oscilloscope and the arbitrary waveform 

generator. The generator is used to convert the signal bursts created by the Monte Carlo 

laser velocimeter simulation program into known frequency electronic signal bursts for 

system testing.

Tektronix TDS 5054B Digital Phosphor Oscilloscope

Along with being a general purpose oscilloscope used during system set-up, it is also a 

critical element in the data acquisition system where it performs three functions. The first 

is to evaluate the quality of the signals obtained from the two laser velocimeter 

components before initiating a data acquisition. This evaluation can identify seeding 

number density problems, e.g., generators running out of particles, and low or mismatched 

signal levels which could be caused by laser or optics misalignment. The second task is to 

provide the user with a visual display of the signal bursts so that the trigger level can be 

set for optimum measurement accuracy. And, finally the oscilloscope provides the trigger 

to initiate the digitization of the signal burst as a particle passes through the measurement 

volume. This trigger also initiates the sampling of the auxiliary channels and 

counter/timer to conditionally sample voltages from other instrumentation and read the 

rotor azimuth encoder. The specifications of the digital oscilloscope are:

• 500 MHz bandwidth;

• 4 channels;

• 8-bit resolution;

• Max 5 GS/s sample rate;

• Max 16 M record length;

IV.4
• Max 100,000 /s waveform capture rate;

• 50-/1000k-ohm input impedance;

• Multiple acquisition modes;

• Multiple triggering modes;

• External trigger output capability.

Agilent 81150A Pulse Function Arbitrary Waveform Generator

Measurement accuracy and instrument precision can be predicted by the Monte Carlo laser 

velocimeter simulation program. This is possible, even with the randomness involved in 

the flow model, photon statistics, etc., since the velocity trajectory of every particle is 

known. Further the particle velocity can be tracked through every phase of signal 

processing to the final statistics. Any differences between the real particle velocity and the 

measured velocity is attributed to instrument precision. Measurement accuracy can be 

determined by comparing the statistical measurements of the generated particle velocities 

with the statistics of the measured velocities, assuming sufficient signal bursts are 

measured to reach statistical stationarity of the flow – real or simulated. Carrying this 

even further, instead of comparing the generated particle velocity statistics, the statistical 

characteristics of the particles actually passing through the measurement volume should 

be compared with the measured velocity statistics to determine the true measurement 

accuracy.

Unfortunately, these theoretical predictions do not provide the actual instrument precision 

or measurement accuracy. Comparisons of the laser velocimeter measurements with other 

techniques or even other laser velocimeter measurements will not provide a measure of 

accuracy since the true velocities are unknown. Only the relative statistical differences 

between the two data sets can be determined.

The solution to this dilemma was to use the signal records developed by the Monte Carlo 

simulation to drive an arbitrary waveform generator and send them to the data acquisition 

system as if they originated from the photomultiplier. A normal data acquisition cycle was 

initiated and the measurements determined from the results of the signal/data processing 

software. Since the particle velocities are now known for particles that yield acceptable 

signal bursts, the real instrument precision can be determined (discounting errors 

attributed to inaccuracies in the optical cross-beam angle which would impose a bias error 

in the mean velocity). As with the simulation, the real measurement accuracy can also be 

determined by comparing the measurement statistics with the input statistical 

characteristics and/or the randomly selected particle velocities. The only point of concern 

was whether the arbitrary waveform generator accurately reproduced the signal burst 

waveforms. A comparison of several signal bursts produced by the simulator with the 

corresponding electronic signals captured by the high-speed digitizer in the PXI system, as 

produced by the arbitrary waveform generator, were identical. Additionally the 

determination of instrument precision and measurement accuracies, this time performed 

IV.5
on the actual hardware, produced results that compared exactly with the predictions from 

the Monte Carlo simulation.

The specifications for the arbitrary waveform generator include:

• 1μ – 120 MHz pulse generation with variable rise/fall time;

• 1μ – 240 MHz sine waveform output;

• 14-bit, 2 GS/s arbitrary waveforms;

• 512k samples, arbitrary waveform memory per channel;

• Noise with a selectable crest factor and signal repetition time of 26 days;

• FM, AM, PW, PWM, FSK modulation capabilities up to 10 MHz;

• 1 or 2 channel, coupled and uncoupled;

• Differential outputs;

• Internal or external triggering capability;

• 50-/1000k-ohm output impedance;

• Fully programmable.

Software

The data acquisition and signal/data processing computers utilized Microsoft Windows 7, 

64-bit Professional as the operating system.

The instrument control and data acquisition software was developed using the National 

Instruments LabVIEW development environment. The program provides the user with an 

easy to navigate interface (GUI) that controls the configuration and operation of the PXI 

data acquisition hardware, transfer of data from the acquisition hardware to permanent 

storage on the hard drives of the data acquisition and signal/data processing computers, 

and constructing the initiation (trigger) file that executes the signal/data processing 

software. The primary capabilities of this software are as follows:

• Hardware initialization and control;

• Data acquisition management;

• Interarrival time recording;

• Conditional sampling of auxiliary signals;

• Data retrieval and archival;

• Scan rig management via GPIB-488 interface.

The details of the installation and operation of the data acquisition and control software 

are given in Appendix C with the specific variable glossary given in Appendix D. The 

details of operating the signal/data processing software along with the glossary of variables 

are given in Appendix E. Additionally several programs were written in support of the 

development of the upgraded laser velocimeter, outlined in Appendix C, and programs to 

assist in post processing the data, outlined in Appendix E.

IV.6
Laboratory Testing of the Upgraded 

14- by 22-Foot Subsonic Tunnel Laser Velocimeter

The first shakedown test of the upgraded laser velocimeter for the 14- by 22-Foot Subsonic 

Tunnel was conducted in the laboratory. The laser velocimeter was configured to operate 

at a focal distance of 4.5-meters, equivalent to reaching tunnel centerline. A small jet flow 

was used to provide an example flow with relatively low turbulence and a centerline 

velocity of approximately 70 m/s. The optical axis was angled approximately 55-degrees 

with the flow centerline because of physical constraints in the laboratory. The objective 

was to determine if the system would yield signals from 1.9-micron PSL particles with 

levels sufficient to yield acceptable velocity measurements. It is noted that 1.9-micron 

particles were used to provide a small safety factor in signal amplitude over the normally 

used 1.7-micron particles. The investigation would also serve as an operational test of the 

data acquisition electronics and software, data transmission to both acquisition and 

processing computers, and automatic data processing and display of the measurement 

results. The test would be conducted in a production mode manner to determine the time 

required for each step in the data acquisition/processing sequence.

The jet flow apparatus was driven by a squirrel cage fan exiting into a 100-mm diameter, 

1.575-m long pipe before entering a series of screens and straws. The pipe necked down to 

a 50-mm diameter, 0.56-m long pipe following the flow straighteners where the flow exits 

to form the low turbulence jet, Figures V.1 and V.2. The optical axis of the laser 

velocimeter passed through the axis of the jet with an inclination angle of approximately 

55-degrees, and located just downstream of the pipe exit, Figure V.1. The seeding particles, 

embedded in a 50:50 solution of water and ethanol, were injected into the inlet of the 

squirrel cage fan using a spray atomizer with 6 Laskin nozzles. Typically only one nozzle 

was used. The 100-mm diameter pipe allowed sufficient transit time for the water/ethanol 

solution to evaporate. The jet flow along with the entrained particles were exhausted to 

the outside of the laboratory by a blower-driven collector.

The center of the laser velocimeter measurement volume was positioned on the flow axis 

and five sets of 10,000 data point ensembles were acquired. The oscilloscope trigger level 

was set to 0.05 V (same level as used in the Monte Carlo simulation: ADC captured signals 

in Figures A.1. - A.7.). Examples of the captured signals by the high-speed digitizer, as 

triggered by the oscilloscope, are shown in Figure V.3. It is noted that all U-component 

signals, which generate the trigger, were virtually identical whereas the V-component 

signals vary by a factor of up to six. All of these signals produced acceptable measurements 

illustrating the robust nature of the signal processing algorithm. Other captures, 

Figure V.4, consisted of a fairly high level noise pulse that was a spontaneous emission 

from the photomultiplier which triggered the oscilloscope. Although these pulses were 

rejected by the signal processing software, their presence reduced the number of potential 

acquisitions of acceptable signal bursts. The seeding rate was sufficient in the jet that the 

noise represented a relatively small percentage of the data. However, when the 

measurement volume was traversed to the shear region at the edge of the jet, the particle 

V.1
data rate was overwhelmed by the noise pulses leaving too few acceptable measurements 

for any statistical meaning, and thus this data was excluded from the following 

comparisons. Histograms of peak signal level for the U- and V-component acquisitions for 

the five ensembles along with an ensemble obtained with the measurement volume located 

at half radius in the jet are shown in Figure V.5. As expected with PSL particles, the 

histograms were virtually identical. The difference between the U-component signal levels 

and the V-component signals was attributed to the lower laser energy in the 0.488-micron 

wavelength used in the V-component.

Each 10,000 element ensemble was acquired in approximately 110 seconds then stored 

locally to the disk drives installed in the data acquisition computer and to disk drives 

residing on the networked data processing computer thus supporting in-situ data backup. 

This redundant transfer of data was fairly slow, but increasing its transfer rate was not 

considered a priority at this time. Once the data was stored on both computers, the 

acquisition computer triggered the signal processing software which then began 

determining the signal frequency of each burst in the ensemble. Processing of the data 

ensembles was completed in approximately 20 seconds and the resolved distributions of 

velocity magnitude, flow angle, and the U- and V- component velocities along with their 

statistical results were presented on the processing computer's monitor. Images of the 

histograms, statistical results, and the full measurement log including interarrival times 

and azimuth angles for each particle were stored in a LOG file for that data ensemble on 

the processing computer. Once complete, the signal processing software automatically 

entered a sleep state where it was idled until the next trigger occurred from the data 

acquisition software. The system was designed to allow another acquisition cycle to be 

initiated after a new trigger pulse was generated by the acquisition program. In practice 

however, acquisition was delayed until the distributions and statistics were displayed. This 

allowed researchers to evaluate whether the data ensemble was acceptable before 

continuing the data acquisition activity.

The next phase of the laboratory investigation was to determine the convergence of the 

measurement statistics, as was performed with the Monte Carlo simulation results. For 

the data convergence study only the Histogram (5) and True Half Power processing 

approaches were used. The simulation results indicated that the Histogram (5) yielded the 

most accurate velocity distribution results, but with slightly greater uncertainties in the 

statistical results. The True Half Power method yielded the most accurate statistical 

results but suffered from “binning” (results that have specific values, not continuous, e.g, 

integer numbers versus floating point – 1.4 would be 1 in integer, but 1.4 in floating point) 

in the distribution results and thus did not produce a true representation of the velocity 

distribution. The convergence results of velocity magnitude, shown in Figure V.6 indicate 

that the mean and standard deviation trends with increased ensemble size were identical 

in form as predicted by the simulation. Additionally the trends show increased sensitivity 

in the standard deviation trends, again as predicted by the simulation. The True Half 

Power converged slightly faster, but both methods reached statistical stationarity with 

ensemble sizes of 2,500. Acceptable convergence occurs at approximately 1,000 signal 

bursts, indicated by a jitter of less than 0.1-m/s out of a “turbulence” of 0.5-m/s found in 

V.2
the 59.2 m/s jet flow (Note: freestream velocity of 72 m/s times cos(35 degrees)). The 

mean velocity magnitude varies approximately 0.2-m/s among the five data ensembles, 

most likely a measure of the long term instability of the fan and potential back pressure 

changes in the collector caused by wind external to the laboratory. This variation appears 

in both processing methods, and thus it was most likely real. These trends remain 

consistent for the flow angle, and the U- and V-component velocity measurements shown 

in Figures V.7-V.9, respectively. However, the flow angle and V-component measurements 

indicate small, but not insignificant differences in their results computed by each method. 

Since the true flow characteristics are unknown, it is impossible to ascertain which 

measurement was correct, and the simulation provided no insight into any differences in 

the statistically stationary results. The question is whether 0.25-degree differences in flow 

angle and its associated standard deviation differences of 0.25-degrees between the two 

processing methods are significant.

As predicted by the simulation, the True Half Power method converged faster, but the 

question “Do the associated velocity and flow angle distributions have the predicted 

characteristics?” remained to be answered. The distribution obtained from each 

processing method for a given data ensemble was then analyzed to determine consistency 

and if any deviations from the expected smooth distributions were found. For example, the 

velocity magnitude of the first ensemble (T144647 14 → hours, 46 minutes, 47 seconds →

time of data acquisition start) is shown in Figure V.10. As predicted by the simulation, the 

Histogram (5) yielded a smooth distribution whereas the True Half Power method showed 

significant binning. For this example all statistical results converge at low ensemble sizes 

and track well between the two methods. These trends continue for the next three data 

ensembles, Figures V.11 to V.13. However, data set T152338, Figure V.14, shows significant 

differences in the skew and excess results between the two processing methods at smaller 

ensemble sizes, but they converged to virtually the same level at larger ensemble sizes.

The flow angle results varied from virtually identical statistical trends to completely 

different with a great variation in convergence results, Figures V.15-V.19. It is also noted 

that the Histogram (5) approach would suddenly change value in skew and excess and 

begin a new convergence trace. The Histogram (5) distributions remained smooth in all 

cases and the True Half Power distributions always contained significant binning. Again 

the significance of these results must be left to the reader. As expected for low turbulent 

centerline flows, the characteristics of the U-component results, Figures V.20-V.24, track 

the characteristics found in the velocity magnitude. Likewise the characteristics of the 

V-component results, Figures V.25-V.29, track the characteristics found in the flow angle.

By moving the measurement volume away from the centerline to the half radius position, 

it was expected that there should be a drop in velocity magnitude and a potential increase 

in flow angle, Figures V.30 and V.31 respectively. While this was the case, the trends found 

at the centerline continued with the statistics, tracking well between the two methods. 

However, the skew and excess results for both methods suddenly jumped to new 

convergences for the velocity magnitude, Figure V.30. Again the U- and V-component 

V.3
results, Figures V.32 and V.33, track the velocity magnitude and flow angle trends, 

respectively.

The laboratory investigation yielded the following conclusions:

1) The trends predicted by the Monte Carlo simulation were found in the laser 

velocimetry measurements:

a) Histogram (5) distributions were smooth, True Half Power distributions were 

binned;

b) There was a distinct convergence of the statistical results as the ensemble size 

was increased;

c) The True Half Power statistics converged faster and had lower excursions at 

small ensemble sizes than the Histogram (5) method; and,

d) In general the two methods yielded virtually identical converged results.

2) There were sudden excursions in the convergence trends by both methods (more 

often in the Histogram (5) method) in skew and excess which caused new 

convergence trends to begin. This might be attributed to an errant data point that 

was not rejected by the data processing software because it remained within the 

threshold limits imposed by the software on the distribution, but significantly 

affected the skew and excess.

3) Measurement standard deviation convergence was more sensitive than the 

convergence of the mean and did not suffer from bias problems as did the mean nor 

did it exhibit sudden excursions as did the skew and excess convergences – thus 

standard deviation will be chosen to be the defining variable for statistical 

convergence.

4) The signal processing techniques proved to be robust based on the number of 

successful coincident measurements even with the variation in the V-component 

signal level. Although this variation may have contributed to the differences found 

in the flow angle and V-component statistics.

5) High-level noise pulses were generated by the photomultipliers; as these signals 

satisfied triggering requirements, they were accepted thus reducing the number of 

valid signal bursts within a given ensemble.

6) U- and V- coincidence measurements were obtained at acceptable rates for 

production testing (90 measurements per second).

7) Data transfer to the acquisition and processing computer hard drives was slow.

8) Automatic signal/data processing was successful and completed within an acceptable 

time with the display of the results being used to assess the data ensemble before 

the next data ensemble was acquired.

9) The more realistic distribution produced by the Histogram (5) method, even though 

the statistical measurements had slightly larger uncertainties, validated its selection 

as the method of choice for final implementation of the signal processing software. 

It is noted that since the original captured signals were saved, off-line processing 

using the same program can be conducted with any of the six processing methods 

described or any new method developed in the future. Manual triggering of the data 

processing program can be achieved by editing the trigger files generated by the data 

V.4
acquisition program during data collection activities that reflect the configuration of 

the targeted data ensemble(s). If more than a few ensembles are to be processed, 

the batch processing program: batchlvprocessing.exe, should be used. This program 

automatically copies the respective trigger file for each data ensemble to the target 

location, making processing totally automated. New processing techniques can also 

be easily incorporated into the existing data processing program by developing a 

subroutine to replace the Histogram (5) subroutine currently installed. It is noted 

that the new subroutine must conform to the calling variable sequence in order to 

compile without error.

V.5
Figure V.1.- Schematic of the 50-mm diameter jet used during laboratory testing of the upgraded laser

velocimeter, along with the location and orientation of the crossing laser beams.

Figure V.2.- Photograph of the 50-mm diameter jet used during laboratory testing of the upgraded laser

velocimeter.

V.6

1.575 m 0.33 m

0.05 m

0.56 m

100 mm

Screen

Straws

Screen

50 mm

1.575 m 0.33 m

0.05 m

0.56 m

100 mm

Screen

Straws

Screen

50 mm

Squirrel Cage Fan 
Figure V.3.- Example signal bursts obtained from 1.9-micron particles embedded in the 2-inch diameter

jet flow, U-component trigger level 0.05 V. Signals produced by the upgraded LV receiver.

V.7

0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

U-component signal level, V

Time, sec

0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

V-component signal level, V

Time, sec

0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

U-component signal level, V

Time, sec

0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

V-component signal level, V

Time, sec

0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

U-component signal level, V

Time, sec

0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

V-component signal level, V

Time, sec
Figure V.4.- Example noise pulses produced by the upgraded LV receiver, U-component trigger level

0.05 V.

V.8

0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

U-component signal level, V

Time, sec

0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

V-component signal level, V

Time, sec

0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

U-component signal level, V

Time, sec

0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

U-component signal level, V

Time, sec

0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

V-component signal level, V

Time, sec

0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

V-component signal level, V

Time, sec
Figure V.5.- Distributions of peak signal level obtained from 1.9-micron particles embedded in the 2-inch

diameter jet flow, U-component trigger level 0.05 V.

V.9

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

500

1000

1500

2000

2500

3000

3500

Number of occurrences

Signal amplitude, V

 U-component

D010710T144647

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

500

1000

1500

2000

2500

3000

3500

Number of occurrences

Signal amplitude, V

 V-component

 U V

Average 0.053 0.025

StDev 0.018 0.012

Old Particles - 1.9 Microns

Pipe Centerline

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

500

1000

1500

2000

2500

3000

3500

Number of occurrences

Signal amplitude, V

 U-component

D010710T145542

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

500

1000

1500

2000

2500

3000

3500

Number of occurrences

Signal amplitude, V

 V-component

 U V

Average 0.053 0.025

StDev 0.019 0.012

Old Particles - 1.9 Microns

Pipe Centerline

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

500

1000

1500

2000

2500

3000

3500

Number of occurrences

Signal amplitude, V

 U-component

D010710T150439

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

500

1000

1500

2000

2500

3000

3500

Number of occurrences

Signal amplitude, V

 V-component

 U V

Average 0.053 0.024

StDev 0.019 0.011

Old Particles - 1.9 Microns

Pipe Centerline

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

500

1000

1500

2000

2500

3000

3500

Number of occurrences

Signal amplitude, V

 U-component

D010710T151427

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

500

1000

1500

2000

2500

3000

3500

Number of occurrences

Signal amplitude, V

 V-component

 U V

Average 0.053 0.025

StDev 0.019 0.012

Old Particles - 1.9 Microns

Pipe Centerline

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

500

1000

1500

2000

2500

3000

3500

Number of occurrences

Signal amplitude, V

 U-component

D010710T152338

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

500

1000

1500

2000

2500

3000

3500

Number of occurrences

Signal amplitude, V

 V-component

 U V

Average 0.053 0.025

StDev 0.019 0.012

Old Particles - 1.9 Microns

Pipe Centerline

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

500

1000

1500

2000

2500

3000

3500

D010710T153437

Number of occurrences

Signal amplitude, V

 U-component

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

500

1000

1500

2000

2500

3000

3500

Number of occurrences

Signal amplitude, V

 V-component

 U V

Average 0.053 0.025

StDev 0.018 0.011

Old Particles - 1.9 Microns

0.5-inch Above Pipe Centerline
Figure V.6.- Convergence of the velocity magnitude mean and standard deviation for five repeated

ensembles at the centerline of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half

Power processing.

V.10

0 500 1000 1500 2000 2500 3000

58.8

58.9

59.0

59.1

59.2

59.3

59.4

59.5

59.6

 T144547

 T145542

 T150439

 T151427

 T152338

Mean velocity magnitude, m/s

Total number in the ensemble

Histogram 5

0 500 1000 1500 2000 2500 3000

58.8

58.9

59.0

59.1

59.2

59.3

59.4

59.5

59.6

 T144547

 T145542

 T150439

 T151427

 T152338

Mean velocity magnitude, m/s

Total number in the ensemble

True Half Power

0 500 1000 1500 2000 2500 3000

0.3

0.4

0.5

0.6

0.7

0.8

 T144547

 T145542

 T150439

 T151427

 T152338

Velocity magnitude standarddeviation, m/s

Total number in the ensemble

Histogram 5

0 500 1000 1500 2000 2500 3000

0.3

0.4

0.5

0.6

0.7

0.8

 T144547

 T145542

 T150439

 T151427

 T152338

Velocity magnitude standarddeviation, m/s

Total number in the ensemble

True Half Power
Figure V.7.- Convergence of the flow angle mean and standard deviation for five repeated ensembles at

the centerline of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power

processing.

V.11

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

 T144547

 T145542

 T150439

 T151427

 T152338

Mean flowangle, degrees

Total number in the ensemble

Histogram 5

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

 T144547

 T145542

 T150439

 T151427

 T152338

Mean flowangle, degrees

Total number in the ensemble

True Half Power

0 500 1000 1500 2000 2500 3000

0.3

0.4

0.5

0.6

0.7

0.8

 T144547

 T145542

 T150439

 T151427

 T152338

Total number in the ensemble

Histogram 5

Flowangle standard deviation, degree

0 500 1000 1500 2000 2500 3000

0.3

0.4

0.5

0.6

0.7

0.8

 T144547

 T145542

 T150439

 T151427

 T152338

Total number in the ensemble

True Half Power

Flowangle standard deviation, degree
Figure V.8.- Convergence of the U-component velocity mean and standard deviation for five repeated

ensembles at the centerline of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half

Power processing.

V.12

0 500 1000 1500 2000 2500 3000

58.8

58.9

59.0

59.1

59.2

59.3

59.4

59.5

59.6

 T144547

 T145542

 T150439

 T151427

 T152338

U-component velocity mean, m/s

Total number in the ensemble

Histogram 5

0 500 1000 1500 2000 2500 3000

58.8

58.9

59.0

59.1

59.2

59.3

59.4

59.5

59.6

 T144547

 T145542

 T150439

 T151427

 T152338

U-component velocity mean, m/s

Total number in the ensemble

True Half Power

0 500 1000 1500 2000 2500 3000

0.2

0.3

0.4

0.5

0.6

0.7

0.8

 T144547

 T145542

 T150439

 T151427

 T152338

U-component velocity standard deviation, m/s

Total number in the ensemble

Histogram 5

0 500 1000 1500 2000 2500 3000

0.2

0.3

0.4

0.5

0.6

0.7

0.8

 T144547

 T145542

 T150439

 T151427

 T152338

U-component velocity standard deviation, m/s

Total number in the ensemble

True Half Power
Figure V.9.- Convergence of the V-component velocity mean and standard deviation for five repeated

ensembles at the centerline of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half

Power processing.

V.13

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

 T144547

 T145542

 T150439

 T151427

 T152338

V-component velocity mean,m/s

Total number in the ensemble

Histogram 5

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

 T144547

 T145542

 T150439

 T151427

 T152338

V-component velocity mean,m/s

Total number in the ensemble

True Half Power

0 500 1000 1500 2000 2500 3000

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

 T144547

 T145542

 T150439

 T151427

 T152338

V-component velocity standard deviation, m/s

Total number in the ensemble

Histogram 5

0 500 1000 1500 2000 2500 3000

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

 T144547

 T145542

 T150439

 T151427

 T152338

V-component velocity standard deviation, m/s

Total number in the ensemble

True Half Power
Figure V.10.- Convergence of the velocity magnitude statistics and full ensemble histograms at the

centerline of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing –

ensemble T144647.

V.14

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

Velocity magnitude, m/s

Cumulative Counts

Histogram (5) True Half Power

0 500 1000 1500 2000 2500 3000

57.4

57.6

57.8

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

Meanvelocity magnitude, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Velocitymagnitude standard deviation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Velocitymagnitudeskew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

Velocity magnitude excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.11.- Convergence of the velocity magnitude statistics and full ensemble histograms at the

centerline of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing –

ensemble T145542.

V.15

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

Velocity magnitude, m/s

Cumulative Counts

Histogram (5) True Half Power

0 500 1000 1500 2000 2500 3000

57.4

57.6

57.8

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

Meanvelocity magnitude, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Velocitymagnitude standard deviation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Velocitymagnitudeskew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

Velocity magnitude excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.12.- Convergence of the velocity magnitude statistics and full ensemble histograms at the

centerline of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing –

ensemble T150439.

V.16

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

Velocity magnitude, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

57.4

57.6

57.8

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

Meanvelocity magnitude, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Velocitymagnitude standard deviation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Velocitymagnitudeskew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

Velocity magnitude excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.13.- Convergence of the velocity magnitude statistics and full ensemble histograms at the

centerline of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing –

ensemble T151427.

V.17

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

Velocity magnitude, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

57.4

57.6

57.8

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

Meanvelocity magnitude, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Velocitymagnitude standard deviation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Velocitymagnitudeskew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

Velocity magnitude excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.14.- Convergence of the velocity magnitude statistics and full ensemble histograms at the

centerline of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing –

ensemble T152338.

V.18

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

Velocity magnitude, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

57.4

57.6

57.8

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

Meanvelocity magnitude, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Velocitymagnitude standard deviation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Velocitymagnitudeskew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

Velocity magnitude excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.15.- Convergence of the flow angle statistics and full ensemble histograms at the centerline of a

2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble

T144647.

V.19

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

Flow angle, degrees

Cumulative Counts

Histogram (5) True Half Power

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

Mean flowangle, degree

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

Flowanglestandard deviation, degree

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Flow angle skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

Flowangleexcess

Number of particles

 Histogram (5)

 True Half Power
Figure V.16.- Convergence of the flow angle statistics and full ensemble histograms at the centerline of a

2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble

T145542.

V.20

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

Flow angle, degrees

Cumulative Counts

Histogram (5) True Half Power

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

Mean flowangle, degree

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

Flowanglestandard deviation, degree

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Flow angle skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

Flowangleexcess

Number of particles

 Histogram (5)

 True Half Power
Figure V.17.- Convergence of the flow angle statistics and full ensemble histograms at the centerline of a

2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble

T150439.

V.21

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

Flow angle, degrees

Cumulative Counts

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

Mean flowangle, degree

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

Flowanglestandard deviation, degree

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Flow angle skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

Flowangleexcess

Number of particles

 Histogram (5)

 True Half Power
Figure V.18.- Convergence of the flow angle statistics and full ensemble histograms at the centerline of a 

2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T151427.

V.22

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

Flow angle, degrees

Cumulative Counts

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

Mean flow angle, degree

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

Flow anglestandard deviation, degree

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Flow angle skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

Flow angleexcess

Number of particles

 Histogram (5)

 True Half Power
Figure V.19.- Convergence of the flow angle statistics and full ensemble histograms at the centerline of a 

2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T152338.

V.23

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

Flow angle, degrees

Cumulative Counts

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

Mean flow angle, degree

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

Flow anglestandard deviation, degree

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Flow angle skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

Flow angleexcess

Number of particles

 Histogram (5)

 True Half Power
Figure V.20.- Convergence of the U-component statistics and full ensemble histograms at the centerline 

of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T144647.

V.24

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

U-component velocity, m/s

Cumulative Counts

Histogram (5) True Half Power

0 500 1000 1500 2000 2500 3000

57.4

57.6

57.8

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

U-component mean, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

U-component standard deviation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

U-component skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

U-component excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.21.- Convergence of the U-component statistics and full ensemble histograms at the centerline 

of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T145542.

V.25

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

U-component velocity, m/s

Cumulative Counts

Histogram (5) True Half Power

0 500 1000 1500 2000 2500 3000

57.4

57.6

57.8

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

U-component mean, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

U-component standard deviation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

U-component skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

U-component excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.22.- Convergence of the U-component statistics and full ensemble histograms at the centerline 

of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T150439.

V.26

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

U-component velocity, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

57.4

57.6

57.8

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

U-component mean, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

U-component standard deviation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

U-component skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

U-component excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.23.- Convergence of the U-component statistics and full ensemble histograms at the centerline 

of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T151427.

V.27

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

U-component velocity, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

57.4

57.6

57.8

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

U-component mean, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

U-component standard deviation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

U-component skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

U-component excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.24.- Convergence of the U-component statistics and full ensemble histograms at the centerline 

of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T152338.

V.28

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

U-component velocity, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

57.4

57.6

57.8

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

U-component mean, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

U-component standard deviation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

U-component skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

U-component excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.25.- Convergence of the V-component statistics and full ensemble histograms at the centerline of 

a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T144647.

V.29

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

V-component velocity, m/s

Cumulative Counts

Histogram (5) True Half Power

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

V-component mean, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

V-component standard devliation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

V-component skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

V-component excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.26.- Convergence of the V-component statistics and full ensemble histograms at the centerline of 

a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T145542.

V.30

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

V-component velocity, m/s

Cumulative Counts

Histogram (5) True Half Power

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

V-component mean, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

V-component standard devliation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

V-component skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

V-component excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.27.- Convergence of the V-component statistics and full ensemble histograms at the centerline of 

a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T150439.

V.31

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

V-component velocity, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

V-component mean, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

V-component standard devliation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

V-component skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

V-component excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.28.- Convergence of the V-component statistics and full ensemble histograms at the centerline of 

a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T151427.

V.32

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

V-component velocity, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

V-component mean, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

V-component standard devliation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

V-component skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

V-component excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.29.- Convergence of the V-component statistics and full ensemble histograms at the centerline of 

a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T152338.

V.33

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

V-component velocity, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

V-component mean, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

V-component standard devliation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

V-component skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

V-component excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.30.- Convergence of the velocity magnitude statistics and histograms at 0.5-inch above centerline of a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – 

ensemble T153437.

V.34

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

Velocity magnitude, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

57.4

57.6

57.8

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

Meanvelocity magnitude, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Velocity magnitude standard deviation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Velocity magnitudeskew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

Velocity magnitude excess

Number of particles

 Histogram (5)

 True Half Power
Figure V.31.- Convergence of the flow angle statistics and histograms at 0.5-inch above center-line of a 2-

inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T153437.

V.35

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

Flow angle, degrees

Cumulative Counts

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

Mean flow angle, degree

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

Flow anglestandard deviation, degree

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Flow angle skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

Flow angleexcess

Number of particles

 Histogram (5)

 True Half Power
Figure V.32.- Convergence of the U-component statistics and histograms at 0.5-inch above center-line of 

a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T153437.

V.36

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

55 56 57 58 59 60 61 62 63 64 65

55 56 57 58 59 60 61 62 63 64 65

0

200

400

600

800

1000

1200

1400

1600

Counts

U-component velocity, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

U-component standard deviation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

U-component skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

U-component excess

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

57.4

57.6

57.8

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

U-component mean, m/s

Number of particles

 Histogram (5)

 True Half Power
Figure V.33.- Convergence of the V-component statistics and histograms at 0.5-inch above center-line of 

a 2-inch diameter jet in the laboratory using Histogram (5) and True Half Power processing – ensemble 

T153437.

V.37

Histogram (5) True Half Power

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

1600

Counts

V-component velocity, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

V-component mean, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

V-component standard devliation, m/s

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

V-component skew

Number of particles

 Histogram (5)

 True Half Power

0 500 1000 1500 2000 2500 3000

-5

0

5

10

15

20

25

V-component excess

Number of particles

 Histogram (5)

 True Half Power
V.38
Evaluation Testing of the Upgraded

14- by 22-Foot Subsonic Tunnel Laser Velocimeter

in the Basic Aerodynamics Research Tunnel

The next phase of the validation of the upgraded laser velocimeter for the 14- by 22-Foot 

Subsonic Tunnel was to measure the flow field about a backward facing step in the Basic 

Aerodynamics Research Tunnel (BART), schematic below. This model was chosen because 

the velocity flow field ranges from low turbulence freestream to a recirculating flow along 

with the associated shear flow region. In addition, this flow field has been previously 

measured by two different fringe-type laser velocimeter systems (Meyers et al (1990) and 

Hart et al (2001)).

The upgraded laser velocimeter was installed in the BART with the final configuration that 

will be used in the 14- by 22-Foot Subsonic Tunnel. The system, shown in Figure VI.1, 

consists of two subsystems. The subsystem containing the final zoom lens and the laser 

transceiver, Figures VI.2-VI.3, would be placed in the tunnel plenum chamber. The laser, 

beam splitting and fiber coupling optics along with the photomultipliers, Figure VI.1, 

would be located in the laser velocimetry laboratory adjacent to the wind tunnel test 

section to protect these components from the harsh environment in the plenum chamber, 

and to allow minor optical adjustments to be made while the tunnel is in operation. The 

two subsystems are connected with a 15-meter-long fiber optic bundle – containing four 

polarization preserving fibers to transmit the laser beams to the transceiver probe and a 

single multi-mode fiber to return the collected scattered light to the photomultipliers, 

Figure VI.4. As shown in Figure VI.4, both subsystems were located in the return leg of 

the BART for the system evaluation test. A photograph of the system in operation with 

the laser beams passing through the freestream flow at the backward facing step location 

is shown in Figure VI.5. The four photo-diode array used to measure the leakage power of 

the four laser beams through the final turning mirror just prior to the zoom lens is shown 

in Figure VI.6. This array provides the feedback needed to adjust the fiber optic coupling 

efficiency of the laser beam should the laser resonator alignment drift during testing.

VI.1

20.5”

3.5”

Flow

24.0”

Basic Aerodynamic Research Tunnel (BART)

X

Y

H
Evaluation of the Laser Velocimeter in Various Flow Fields

The first part of the evaluation was to obtain large data ensembles at several locations 

about the step to determine the statistical convergence characteristics in freestream, shear 

region, and reverse flows. The primary question was whether the statistics converged in 

the manner found in the simulation and laboratory tests, and to see if convergence varies 

with flow conditions. Since the laboratory tests indicated that the Histogram (5) approach 

provided a better representation of the flow velocity distributions, it was the only 

processing method used during this investigation. The 1.7-micron PSL particles, 

suspended in a 50:50 mixture of water and ethanol, were injected at the tunnel inlet using 

two paint sprayers. The measurement volume was set above the 3.5-inch step and slightly 

downstream (y/H = 0.34, x/H = 0.32) to evaluate the system in freestream conditions. The 

freestream velocity was set to 16.6 m/s. Four data ensembles were acquired, each with 

5,000 measurements, with the distribution for all measurements plotted along with the 

convergence statistics for the first 3,000 measurements of each ensemble. The results for 

the velocity magnitude are shown in Figure VI.7. The distribution was nearly Gaussian as 

would be expected in the freestream and the convergences occur almost immediately in the 

standard deviation with very small differences (~20 mm/s) in the stationary values. It is 

also noted that the convergence plots do not extend to 3,000 data points because the lower 

data rate, as compared to the laboratory tests, allowed the noise pulses described in 

Chapter V and shown in Figure V.4, to become a significant fraction of the data ensemble. 

These trends continued with the flow angle, U- and V-component velocity results, 

Figures VI.8-VI.10 respectively. It is also noted that, as with the laboratory data, the flow 

angle and V-component velocity means had larger differences among the four stationary 

values, in this case by 1.4-degrees and 0.4 m/s respectively. The distributions for each of 

the four ensembles are shown in Figures VI.11-VI.14. Although there are slight differences 

among the distributions, the overall characteristics remain very similar for the four 

ensembles.

This process was repeated with the measurement volume located in the shear region just 

downstream of the step (y/H = -0.17, x/H = 0.32). In this case the velocity magnitude 

distribution, Figure VI.15, has decreased indicating that the measurement volume is below 

freestream, yet the skew toward higher velocities may indicate some influence of 

freestream. The convergence of the standard deviation was very rapid for this data 

ensemble – approximately 700 measurements. However only 1,250 signal bursts were 

processed, an indication that the data rate was lower than freestream as expected, with a 

corresponding increase in the number of spurious noise pulses within the ensemble. 

Moving to the flow angle results, Figure VI.16, the peak of the distribution was located at 

130-degrees. The U- and V-component velocity distributions, Figures VI-17-VI.18, were 

nearly Gaussian which may indicate that a coupling of the component velocities caused the 

skew in the velocity magnitude distribution and not freestream. Based on these 

distributions, the flow at this location was directed upstream with an upward angle of 

50-degrees indicating that this location was near the top of the upstream portion of the 

primary separation vortex. However the large spread in the flow angle distribution also 

appears to indicate that the flow is very turbulent with angles extending from the 

VI.2
freestream direction to fully reversed flow. At this position, the flow was varying about 

1.4-m/s in the x-axis and 0.9-m/s in the vertical axis. The separation in mean flow angle 

and V-component velocity found in the freestream data was not as noticeable at this 

location, but then again convergence did not occur in the flow angle or the V-component 

standard deviations. The individual distributions are shown in Figures VI.19-VI.22.

The measurement volume was then moved further downstream directly behind the top of 

the step (y/H = 0.0, x/H = 0.69). This should have located the measurement volume in the 

primary shear region between the freestream flow and the recirculation zone. In this case 

the distribution of the velocity magnitude, Figure VI.23, had a marked skew toward lower 

velocities indicating the presence of the recirculation zone part of the time, with the peak 

of the distribution approximately 20-percent below the freestream velocity. Based on 

previous studies, Meyers et al (1990), Meyers (1991), this location should have generated 

measurements that had a fairly high velocity:data rate correlation indicating the presence 

of particle sampling bias. Also, as shown by Meyers (1991), the level and sign of the 

correlation coefficient was also dependent on the measurement instrumentation. In this 

case the data rate was sufficiently low so that there was no correlation indicating that each 

measurement was truly an independent measure of the flow. However, it does not confirm 

that sampling bias was not present because the physics of two interacting flows with 

different seeding densities would still produce a bias. This will be addressed again when 

the current measurements are compared with the results from previous investigations. 

The number of signal bursts acquired increased at this location because of the high seeding 

density in the freestream. However the high “turbulence” in this region, greater than 

10-percent of freestream, delayed convergence of the velocity magnitude standard 

deviation until 2,500 signal bursts were included in the ensemble. Excess statistics never 

converged for this data ensemble. As seen in Figure VI.24, the flow angle was directed 

approximately 5-degrees downward indicating that the freestream flow was expanding to 

fill the void behind the separation zone which also explains the lower mean velocity 

magnitude. The U- and V-component results are shown in Figures VI.25-VI.26 and the 

individual distributions shown in Figures VI.27-VI.30.

The measurement volume was then positioned deep within the separation zone at this 

downstream location (y/H = -0.40, x/H = 0.69). This location should provide a strong 

reverse flow with relatively low influence from freestream. The results presented in 

Figures VI.31-VI.34 indicate nearly Gaussian distributions in the U- and V-components and 

rapid convergence of the standard deviations occurring at approximately 1,500 signal 

bursts. However, the number of measurements was unexpectedly high with the noise 

pulses making a much smaller contribution. The distribution characteristics were similar 

to the results obtained at y/H = -0.17, x/H = 0.32, except the peak of the flow angle 

distribution was approximately 150-degrees. The Gaussian distributions in the U- and 

V-components indicated that there was no influence from freestream at this location as 

expected, and that the measurement volume was positioned at the upstream part of the 

primary separation vortex, but lower since the flow angle was approaching horizontal. The 

individual distributions are given in Figures VI.35-VI.38. 

VI.3
The final measurement location was slightly below the top of the step and further 

downstream (y/H = -0.17, x/H =1.37). The flow in this region should be an expansion of 

the freestream with a fair amount of turbulence as the shear layer mixing would be more 

significant. The results, Figures VI.39-VI.42, indicate that the turbulence was 

approximately 20-percent of the local mean velocity indicating that for a period of time the 

flow was in the upstream direction, Figure VI.41. Here again the data rate was fairly high 

and the flow was primarily in the downstream direction, but occasionally a portion of the 

separated flow passes through the measurement volume as indicated by the low level, 

noise-like segments in the flow angle distribution, Figure VI.40. Here again the standard 

deviation convergence was quite rapid occurring at approximately 1,500 signal bursts. The 

individual distributions are shown in Figures VI.43-VI.46.

In summary for this portion of the laser velocimeter evaluation, the performance was very 

similar to that observed during laboratory testing. The use of standard deviation 

convergence proved to be a good indicator of the realization of statistical stationarity. The 

spurious voltage pulses spontaneously generated by the photomultiplier were still present 

and had a significant influence on the number of signal bursts acquired, especially with the 

low data rates found in the separated region. The distributions appeared nearly Gaussian 

except in the shear region where the expected skew was found. The velocity:data rate 

correlations were nominally zero indicating that the measurements were independent; 

however there were also indications that particle sampling bias was still present. When 

comparing these findings with previous investigations there appears to be two parts to the 

origin of the sampling bias: 1) the influence of the instrumentation in accepting 

measurements, as shown by Meyers (1991) when the correlation coefficient changed signs 

after the instrument dead time was changed, and 2) the physical characteristics involved 

when two adjacent flows with different seed densities mix. 

Comparison With Other Measurements

Although the Monte Carlo simulation results indicated that the precision of the upgraded 

laser velocimeter was better than 0.3-m/s at a velocity of 100 m/s (even with direct measure 

of the 40-MHz Bragg shifted signal), a comparison with previous measurements of the 

same/similar flow is the true indicator as to system performance. The comparison data 

were obtained from two sources:

1) One component laser velocimeter measurements using the dedicated short focal 

length system in the BART to measure about a 1.5-inch backward facing step 

with a freestream velocity of 45 m/s (Hart et al (2001); and,

2) Three component laser velocimeter measurements using a 1-meter focal length 

system in a 6-inch channel with a 3-inch backward facing step and a freestream 

velocity of 50 m/s (Meyers et al (1990)).

Since the first source used a 1.5-inch step, the 3.5-inch step was removed from the test 

section and the 1.5-inch step inserted and further velocity measurements obtained. 

VI.4
Measurement volume location was normalized by step height so that data from both steps 

could be included in the comparisons. The freestream velocity was maintained at 16.6 m/s 

during all testing with only a single scan obtained with a freestream velocity of 45 m/s at 

the furthest downstream location (x/H = 1.6) using the 1.5-inch step. Here again, to allow 

direct comparison among the various freestream velocities, all measured velocities were 

normalized by freestream.

The first task in this comparative investigation was to determine if there was any 

indication of particle sampling bias. Using the velocity:data rate correlation coefficient in 

the manner described by Meyers et al (1990), the coefficient traces were plotted for both 

steps, Figure VI.47. The results from the 3.5-inch step investigation indicate a zero 

correlation in freestream at all stations, then a slow trend in the negative direction until 

approximately y/H = 0.3 where the correlation remains at -0.1. Likewise the results from 

the 1.5-inch step investigation indicate a zero correlation in freestream, but the trend in 

the negative direction did not begin until y/H = 0.4 with no indication of flattening even 

when the correlation reaches -0.15 at the lowest point measured. The estimated 

correlation time (Meyers et al (1990)), shown in Figure VI.47, was short in freestream 

increasing through the shear layer and fairly long, approximately 0.15 seconds, within the 

separated flow region for both steps. The long excursions shown in the figures were 

caused by very low data rates. These trends are in agreement which those found by 

Meyers et al (1990), but not to the level previously found. This was most likely the 

influence of the longer instrument dead time (time when the data acquisition system 

cannot accept a new measurement because it is processing/storing the current signal burst) 

of the current system.

During a Laser Induced Thermal Acoustics (LITA) proof of concept test (Hart et al (2001)), 

the dedicated laser velocimeter in the BART was used to establish the velocity 

characteristics of the flow. The laser velocimetry measurements were made at x/H = 0.53 

downstream of the 1.5-inch step with a freestream velocity of 45.0 m/s. The mean and 

standard deviation profiles measured at that location for three separate traverses are 

shown in Figure VI.48. The overlaid profiles for the current investigation are also shown 

in the Figure along with an overlay of both data sets near x/H = 0.53. Although the trends 

are very similar, there are differences in the slope of the mean velocity and the location of 

the maximum standard deviations. These differences are most likely due to the differences 

in the freestream velocity: 45.0 m/s for the previous investigation and 15.24 m/s for the 

current investigation. A further comparison is presented in Figure VI.49., where the 

vertical traverse obtained in the original investigation at x/H = 6.64 is included, and the 

current investigation about the 3.5-inch step is added. A visual comparison between the 

current data obtained from the two step heights clearly shows that they are not scalable. 

This visual difference in the data traces is accentuated by the overlays in the scaled 

velocity and flow region comparison. Here again the mean velocity near freestream and 

deep within the recirculation region match, but there are differences between the two 

investigations through the shear region. Although scalability was one problem, 

measurement volume size may also influence spatial averaging within this region. The 

problem with scalability based on step height is clearly seen with the overlay of the 

VI.5
standard deviations. There is no match between the data obtained with the 3.5-inch step 

and the other data except when the sampling bias noise floor is reached below the shear 

layer. However, the current data obtained from the 1.5-inch step is a reasonable match 

with the previous data except at and just below the peak of the turbulence – again this may 

be traced to the differences in measurement volume size and the associated averaging of 

the particle velocities.

The final comparison was obtained in a channel flow where the step height was 3-inches, 

half the height of the downstream channel, Figure VI.50 (Meyers et al (1990)). Although a 

three-component laser velocimeter was used, only the U-component velocity profiles would 

be compared and those only to the extent where the measurement locations were 

approximately the same. A photograph of the installation is shown in Figure VI.51 and the 

measured mean velocity and standard deviation maps are shown in Figure VI.52. Again 

the comparable scans for the previous investigation along with a repeat of the current 

investigation are shown in Figure VI.53. Here the basic trends of the data are similar, but 

not directly comparable. The peak standard deviations did not occur at the same location 

but had approximately the same amplitude. The residual standard deviations below the 

shear regions nearly match along with the mean velocity in the same region. Based on the 

inability to scale measurement location with step height as determined above, along with 

the potential influence of the channel ceiling on the flow field, one should expect 

differences between the results of the two investigations. However, the trends indicate 

that sampling bias is an issue of concern since the previous investigation found significant 

velocity:data rate correlations that varied with location while the current investigation had 

far less of an indication. The instrument-based biases were corrected in the previous 

investigation resulting in the data used for this comparison. Thus both data sets were 

derived from independent measures of the flow field, but both were still influenced by 

sampling bias. If the velocity:data rate correlation can not be used as an indicator of 

particle sampling bias, then another indicator must be found to provide the researcher 

with information as to when the measurements would be accurate. 

In order to insure that particle dynamics were not an issue regarding the fidelity of the 

flow measurements with the current system, signal level distributions were determined for 

a scan downstream of the 1.5-inch step (x/H = 1.6). Several sizes of PSL particles were 

used with the 50:50 mixture of water and ethanol and injected into the flow with the same 

paint sprayers. The theoretical distribution of signal levels for 1.7-micron particles passing 

randomly through the measurement volume is shown in Figure VI.54. Also the 

distribution of signal levels obtained in the laboratory using the Royco particle generator is 

also shown in Figure VI.54. A comparison of the two distributions show consistency, as do 

the distributions obtained from the 2-inch jet flow, Figure V.5. The distributions of signal 

level from 0.68-micron and 1.7-micron particles are shown in Figure VI.55 as a function of 

vertical distance. While the distributions obtained from the 0.68-micron particles are 

similar to the theoretical and laboratory distributions, the 1.7-micron distribution is totally 

different producing considerably higher signal levels. These distributions remain the same 

until the shear layer was entered where the 1.7-micron signal levels begin to reduce until 

the bottom of the scan is reached (y/H = -0.47). Here the distributions become similar to 

VI.6
the theoretical and laboratory distributions. This change in distribution is characteristic 

of an evaporating liquid particle. There would be little evaporation in freestream because 

of the lower transit time between particle generation and measurement location versus the 

longer transit time experienced by a particle entrained in the recirculation zone. Since the 

distributions for the 0.68-micron particles did not vary, it must be concluded that the 

amount of liquid attached to these particles was far less which evaporated before the test 

section was reached. Thus it appears that the use of the paint sprayer may have affected 

the results of the current investigation. A direct comparison with signal levels from the 

previous investigations is not possible as the instrumentation used did not preserve the 

signals.

In summary, the comparative investigation indicates that the upgraded laser velocimeter 

yields data comparable with previous investigations, however allowances must be made for 

differences in freestream velocity and step heights. The following conclusions can be made 

based on this comparative investigation:

1) Given the differences in the investigations, the current system yielded 

measurements that traced the main structures within the flow found in the 

previous investigations.

2) All measurement distributions were smooth and most nearly Gaussian, with the 

only exceptions being in the region of the shear layer where skewed 

distributions would be expected – thus the Histogram (5) method performs as 

predicted and as was found in the laboratory experiments.

3) The statistical convergence method also performed as predicted and as found in 

the laboratory to determine at which ensemble size statistical stationarity was 

reached.

4) The distribution of signal levels indicate that the water:ethanol used to 

transport the 1.7-micron PSL particles from the paint sprayer in the current 

investigation did not fully evaporate, which may have affected the measurement 

accuracy.

5) The Monte Carlo simulation investigation indicated that the measurement 

precision of the upgraded system was better than 0.3 m/s and that measurement 

accuracy was highly dependent on the number of measurements obtained before 

the statistics were calculated. Based on the simulation results, laboratory 

findings, and the comparative results presented above, it can be concluded that 

the upgraded laser velocimeter satisfies the required ±1.5 m/s accuracy – 

provided sufficient signal bursts are processed to reach statistical stationarity.

Recommendations

During the simulation, laboratory and especially the comparative investigations in the 

BART, several areas needing attention were found which generated the following 

recommendations:

VI.7
1) Develop a method to eliminate the spurious electronic pulses spontaneously 

generated by the photomultiplier which lead to false triggers in the data 

acquisition system – A circuit has been designed, built and tested that eliminates 

these spurious pulses from the signal before it reaches the data acquisition 

system: problem eliminated.

2) Develop a method to increase data transfer speeds to reasonable levels for 

production testing – Software has been developed to increase the transfer speed 

by almost an order of magnitude to bring the transfer times to acceptable levels.

3) Improve measurement accuracy by better defining the extent of the 

measurement distributions – Data processing software was improved to yield 

better accuracies than obtained previously. It is noted that all data, simulation 

and measurements, were reprocessed using the new software and the results 

presented in this document were obtained using the new software.

4) Develop a method to use the convergence of the measured standard deviations 

as a function of ensemble size to determine when statistical stationarity is 

reached and provide feedback to the data acquisition system when sufficient 

data has been acquired – To be implemented in the future.

5) Develop a method to separate bi-modal velocity distributions so that each of the 

two flows can be studied together and separately – To be implemented in the 

future.

6) Use Monte Carlo simulation techniques to determine the measurement precision 

of other velocimeters, e.g., PIV, LITA, pDv, DGV, Rayleigh, etc.

VI.8
Figure VI.1.- Upgraded 14- by 22-Foot Subsonic Tunnel laser velocimeter optics system.

Figure VI.2.- Subsystem of the upgraded laser velocimeter that will be placed in the tunnel plenum chamber.

VI.9
Figure VI.3.- Subsystem of the upgraded laser velocimeter that will be placed in the tunnel plenum chamber.

Figure VI.4.- Subsystem of the upgraded laser velocimeter that will be placed in the tunnel plenum chamber 

connected with the subsystem and laser that will be placed outside the tunnel via fiber optics.

VI.10
Figure VI.5.- Upgraded laser velocimeter under test in the BART – Measure the velocity flow field about a 

backward facing step.

Figure VI.6.- Prototype optical alignment sensor that will provide the signals needed to remotely realign the LV 

transmission optical system should there be alignment drifts caused by the wind tunnel environment.

VI.11
Figure VI.7.- Convergence of the velocity magnitude statistics and full ensemble histogram in the freestream 

area above of the backward facing step (y/H = 0.34, x/H = 0.32).

VI.12

0.01

0.5

2

10

30

50

70

90

98

99.5

15 16 17 18

15 16 17 18

0

200

400

600

800

1000

1200

1400

Counts

Velocity magnitude, m/s

CumulativeCounts

0 500 1000 1500 2000 2500 3000

16.58

16.60

16.62

16.64

16.66

16.68

16.70

16.72

16.74

16.76

16.78

16.80

16.82

Mean velocity magnitude, m/s

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341

0 500 1000 1500 2000 2500 3000

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Velocity magnitude excess

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341

0 500 1000 1500 2000 2500 3000

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

Velocity magnitudeskew

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341

0 500 1000 1500 2000 2500 3000

0.17

0.18

0.19

0.20

0.21

0.22

0.23

0.24

0.25

0.26

0.27

0.28

0.29

Velocity magnitude standarddeviation, m/s

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341
Figure VI.8.- Convergence of the flow angle statistics and full ensemble histogram in the freestream area above 

of the backward facing step (y/H = 0.34, x/H = 0.32).

VI.13

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2

-6 -4 -2 0 2

0

100

200

300

400

500

Counts

Flow angle, degrees

CumulativeCounts

0 500 1000 1500 2000 2500 3000

-3.4

-3.2

-3.0

-2.8

-2.6

-2.4

-2.2

-2.0

-1.8

-1.6

-1.4

-1.2

-1.0

Meanflowangle, degrees

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341

0 500 1000 1500 2000 2500 3000

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

Flowangleexcess

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341

0 500 1000 1500 2000 2500 3000

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

Flowangle skew

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341

0 500 1000 1500 2000 2500 3000

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

Flowangle standard deviation, degrees

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341
Figure VI.9.- Convergence of the U-component velocity statistics and full ensemble histogram in the freestream 

area above of the backward facing step (y/H = 0.34, x/H = 0.32).

VI.14

0.01

0.5

2

10

30

50

70

90

98

99.5

15 16 17 18

15 16 17 18

0

200

400

600

800

1000

1200

1400

Counts

U-component velocity, m/s

CumulativeCounts

0 500 1000 1500 2000 2500 3000

16.58

16.60

16.62

16.64

16.66

16.68

16.70

16.72

16.74

16.76

16.78

16.80

16.82

 T121016

 T121749

 T122518

 T123341

U-component velocity mean, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

0.17

0.18

0.19

0.20

0.21

0.22

0.23

0.24

0.25

0.26

0.27

0.28

0.29

 T121016

 T121749

 T122518

 T123341

U-component velocity standard deviation, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

U-component velocity skew

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341

0 500 1000 1500 2000 2500 3000

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

U-component velocity excess

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341
Figure VI.10.- Convergence of the V-component velocity statistics and full ensemble histogram in the freestream 

area above of the backward facing step (y/H = 0.34, x/H = 0.32).

VI.15

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

200

400

600

800

1000

1200

1400

Counts

V-component velocity, m/s

CumulativeCounts

0 500 1000 1500 2000 2500 3000

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

V-component velocity mean, m/s

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341

0 500 1000 1500 2000 2500 3000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

V-component velocity excess

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341

0 500 1000 1500 2000 2500 3000

0.3

0.4

0.5

0.6

V-component velocity standard deviation, m/s

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341

0 500 1000 1500 2000 2500 3000

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

V-component velocity skew

Total number in the ensemble

 T121016

 T121749

 T122518

 T123341
Figure VI.11.- Distribution of velocity magnitude for the individual data ensembles in the freestream area above 

of the backward facing step (y/H = 0.34, x/H = 0.32).

VI.16

0.01

0.5

2

10

30

50

70

90

98

99.5

15 16 17 18

15 16 17 18

0

50

100

150

200

250

300

350

400

450

500

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

15 16 17 18

15 16 17 18

0

50

100

150

200

250

300

350

400

450

500

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

15 16 17 18

15 16 17 18

0

50

100

150

200

250

300

350

400

450

500

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

15 16 17 18

15 16 17 18

0

50

100

150

200

250

300

350

400

450

500

Counts

Velocity magnitude, m/s

Cumulative Counts

D020410T121016 D020410T121749

D020410T122518 D020410T123341
Figure VI.12.- Distribution of flow angle for the individual data ensembles in the freestream area above of the 

backward facing step (y/H = 0.34, x/H = 0.32).

VI.17

D020410T121016 D020410T121749

D020410T122518 D020410T123341

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2

-6 -4 -2 0 2

0

50

100

150

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2

-6 -4 -2 0 2

0

50

100

150

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2

-6 -4 -2 0 2

0

50

100

150

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2

-6 -4 -2 0 2

0

50

100

150

Counts

Flow angle, degrees

Cumulative Counts
Figure VI.13.- Distribution of U-component velocity for the individual data ensembles in the freestream area 

above of the backward facing step (y/H = 0.34, x/H = 0.32).

VI.18

D020410T121016 D020410T121749

D020410T122518 D020410T123341

0.01

0.5

2

10

30

50

70

90

98

99.5

15 16 17 18

15 16 17 18

0

50

100

150

200

250

300

350

400

450

500

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

15 16 17 18

15 16 17 18

0

50

100

150

200

250

300

350

400

450

500

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

15 16 17 18

15 16 17 18

0

50

100

150

200

250

300

350

400

450

500

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

15 16 17 18

15 16 17 18

0

50

100

150

200

250

300

350

400

450

500

Counts

U-component velocity, m/s

Cumulative Counts
Figure VI.14.- Distribution of V-component velocity for the individual data ensembles in the freestream area 

above of the backward facing step (y/H = 0.34, x/H = 0.32).

VI.19

D020410T121016 D020410T121749

D020410T122518 D020410T123341

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

50

100

150

200

250

300

350

400

450

500

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

50

100

150

200

250

300

350

400

450

500

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

50

100

150

200

250

300

350

400

450

500

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

50

100

150

200

250

300

350

400

450

500

Counts

V-component velocity, m/s

Cumulative Counts
Figure VI.15.- Convergence of the velocity magnitude statistics and full ensemble histogram in the shear flow 

region just behind the backward facing step (y/H = -0.17, x/H = 0.32).

VI.20

0.01

0.5

2

10

30

50

70

90

98

99.5

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7

0

100

200

300

400

500

600

700

800

Counts

Velocity magnitude, m/s

CumulativeCounts

0 500 1000 1500 2000 2500 3000

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

Velocity magnitude excess

Total number in the ensemble

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

0 500 1000 1500 2000 2500 3000

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

Velocity magnitudeskew

Total number in the ensemble

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

0 500 1000 1500 2000 2500 3000

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

Velocity magnitude standarddeviation, m/s

Total number in the ensemble

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

0 500 1000 1500 2000 2500 3000

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

Mean velocity magnitude, m/s

Total number in the ensemble

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351
Figure VI.16.- Convergence of the flow angle statistics and full ensemble histogram in the shear flow region just 

behind the backward facing step (y/H = -0.17, x/H = 0.32).

VI.21

0.01

0.5

2

10

30

50

70

90

98

99.5

0 30 60 90 120 150 180 210 240 270 300 330 360

0 30 60 90 120 150 180 210 240 270 300 330 360

0

50

100

150

200

250

300

350

400

Counts

Flow angle, degrees

CumulativeCounts

0 500 1000 1500 2000 2500 3000

40

50

60

70

80

90

100

110

Flow angle standard deviation, degrees

Total number in the ensemble

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

0 500 1000 1500 2000 2500 3000

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Flowangle skew

Total number in the ensemble

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

0 500 1000 1500 2000 2500 3000

1.8

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

3.8

4.0

4.2

4.4

4.6

4.8

Flow angleexcess

Total number in the ensemble

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

0 500 1000 1500 2000 2500 3000

90

95

100

105

110

115

120

125

130

135

140

145

150

Meanflowangle, degrees

Total number in the ensemble
Figure VI.17.- Convergence of the U-component velocity statistics and full ensemble histogram in the shear flow 

region just behind the backward facing step (y/H = -0.17, x/H = 0.32).

VI.22

0.01

0.5

2

10

30

50

70

90

98

99.5

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

0

100

200

300

400

500

600

700

800

Counts

U-component velocity, m/s

CumulativeCounts

0 500 1000 1500 2000 2500 3000

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

U-component velocitymean, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

U-component velocitystandard deviation, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

U-component velocityskew

Total number in the ensemble

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

0 500 1000 1500 2000 2500 3000

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

U-component velocity excess

Total number in the ensemble
Figure VI.18.- Convergence of the V-component velocity statistics and full ensemble histogram in the shear flow 

region just behind the backward facing step (y/H = -0.17, x/H = 0.32).

VI.23

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

100

200

300

400

500

600

700

800

Counts

V-component velocity, m/s

CumulativeCounts

0 500 1000 1500 2000 2500 3000

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

V-component velocity mean, m/s

Total number in the ensemble

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

0 500 1000 1500 2000 2500 3000

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

V-component velocity excess

Total number in the ensemble

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

0 500 1000 1500 2000 2500 3000

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

V-component velocity skew

Total number in the ensemble

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351

0 500 1000 1500 2000 2500 3000

0.6

0.7

0.8

0.9

1.0

1.1

1.2

V-component velocity standard deviation, m/s

Total number in the ensemble

 T125104

 T130440

 T131538

 T133433

 T134402

 T135351
Figure VI.19.- Distribution of velocity magnitude for the individual data ensembles in the shear flow region just 

behind the backward facing step (y/H = -0.17, x/H = 0.32).

VI.24

0.01

0.5

2

10

30

50

70

90

98

99.5

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7

0

50

100

150

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7

0

50

100

150

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7

0

50

100

150

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7

0

50

100

150

Counts

Velocity magnitude, m/s

Cumulative Counts

D020410T125104 D020410T130440

D020410T131538 D020410T133433
Figure VI.19 (cont'd).- Distribution of velocity magnitude for the individual data ensembles in the shear flow 

region just behind the backward facing step (y/H = -0.17, x/H = 0.32).

VI.25

0.01

0.5

2

10

30

50

70

90

98

99.5

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7

0

50

100

150

Counts

Velocity magnitude, m/s

CumulativeCounts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7

0

50

100

150

Counts

Velocity magnitude, m/s

CumulativeCounts

D020410T134402 D020410T135351
Figure VI.20.- Distribution of flow angle for the individual data ensembles in the shear flow region just behind the 

backward facing step (y/H = -0.17, x/H = 0.32).

VI.26

D020410T125104 D020410T130440

D020410T131538 D020410T133433

0.01

0.5

2

10

30

50

70

90

98

99.5

0 30 60 90 120 150 180 210 240 270 300 330 360

0 30 60 90 120 150 180 210 240 270 300 330 360

0

10

20

30

40

50

60

70

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 30 60 90 120 150 180 210 240 270 300 330 360

0 30 60 90 120 150 180 210 240 270 300 330 360

0

10

20

30

40

50

60

70

80

90

100

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 30 60 90 120 150 180 210 240 270 300 330 360

0 30 60 90 120 150 180 210 240 270 300 330 360

0

10

20

30

40

50

60

70

80

90

100

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 30 60 90 120 150 180 210 240 270 300 330 360

0 30 60 90 120 150 180 210 240 270 300 330 360

0

10

20

30

40

50

60

70

80

90

100

Counts

Flow angle, degrees

Cumulative Counts
Figure VI.20 (cont'd).- Distribution of flow angle for the individual data ensembles in the shear flow region just 

behind the backward facing step (y/H = -0.17, x/H = 0.32).

VI.27

D020410T134402 D020410T135351

0.01

0.5

2

10

30

50

70

90

98

99.5

0 30 60 90 120 150 180 210 240 270 300 330 360

0 30 60 90 120 150 180 210 240 270 300 330 360

0

10

20

30

40

50

60

70

80

90

100

Counts

Flow angle, degrees

CumulativeCounts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 30 60 90 120 150 180 210 240 270 300 330 360

0 30 60 90 120 150 180 210 240 270 300 330 360

0

10

20

30

40

50

60

70

80

90

100

Counts

Flow angle, degrees

CumulativeCounts
Figure VI.21.- Distribution of U-component velocity for the individual data ensembles in the shear flow region just 

behind the backward facing step (y/H = -0.17, x/H = 0.32).

VI.28

D020410T125104 D020410T130440

D020410T131538 D020410T133433

0.01

0.5

2

10

30

50

70

90

98

99.5

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

0

50

100

150

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

0

50

100

150

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

0

50

100

150

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

0

50

100

150

Counts

U-component velocity, m/s

Cumulative Counts
Figure VI.21 (cont'd).- Distribution of U-component velocity for the individual data ensembles in the shear flow 

region just behind the backward facing step (y/H = -0.17, x/H = 0.32).

VI.29

D020410T134402 D020410T135351

0.01

0.5

2

10

30

50

70

90

98

99.5

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

0

50

100

150

Counts

U-component velocity, m/s

CumulativeCounts

0.01

0.5

2

10

30

50

70

90

98

99.5

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4

0

50

100

150

Counts

U-component velocity, m/s

CumulativeCounts
Figure VI.22.- Distribution of V-component velocity for the individual data ensembles in the shear flow region just 

behind the backward facing step (y/H = -0.17, x/H = 0.32).

VI.30

D020410T125104 D020410T130440

D020410T131538 D020410T133433

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

50

100

150

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

50

100

150

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

50

100

150

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

50

100

150

Counts

V-component velocity, m/s

Cumulative Counts
Figure VI.22 (cont'd).- Distribution of V-component velocity for the individual data ensembles in the shear flow 

region just behind the backward facing step (y/H = -0.17, x/H = 0.32).

VI.31

D020410T134402 D020410T135351

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

50

100

150

Counts

V-component velocity, m/s

CumulativeCounts

0.01

0.5

2

10

30

50

70

90

98

99.5

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5 -4 -3 -2 -1 0 1 2 3 4 5

0

50

100

150

Counts

V-component velocity, m/s

CumulativeCounts
Figure VI.23.- Convergence of the velocity magnitude statistics and full ensemble histogram in the region directly 

behind the backward facing step (y/H = 0.0, x/H = 0.69).

VI.32

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16 18 20

0 2 4 6 8 10 12 14 16 18 20

0

100

200

300

400

500

600

Counts

Velocity magnitude, m/s

CumulativeCounts

0 500 1000 1500 2000 2500 3000

12.0

12.1

12.2

12.3

12.4

12.5

12.6

12.7

12.8

12.9

13.0

13.1

 T140216

 T143550

 T144414

Mean velocitymagnitude, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

 T140216

 T143550

 T144414

Velocity magnitude standarddeviation, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

 T140216

 T143550

 T144414

Velocitymagnitudeskew

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

 T140216

 T143550

 T144414

Velocitymagnitude excess

Total number in the ensemble
Figure VI.24.- Convergence of the flow angle statistics and full ensemble histogram in the region directly behind 

the backward facing step (y/H = 0.0, x/H = 0.69).

VI.33

0.01

0.5

2

10

30

50

70

90

98

99.5

-30 -20 -10 0 10 20 30

-30 -20 -10 0 10 20 30

0

100

200

300

400

500

600

Counts

Flow angle, degrees

CumulativeCounts

0 500 1000 1500 2000 2500 3000

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

 T140216

 T143550

 T144414

Meanflowangle, degrees

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

 T140216

 T143550

Flowangle standard deviation, degrees

 T144414

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

0.0

0.5

1.0

1.5

2.0

2.5

 T140216

 T143550

 T144414

Flowangle skew

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

 T140216

 T143550

 T144414

Flowangleexcess

Total number in the ensemble
Figure VI.25.- Convergence of the U-component velocity statistics and full ensemble histogram in the region 

directly behind the backward facing step (y/H = 0.0, x/H = 0.69).

VI.34

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16 18 20

0 2 4 6 8 10 12 14 16 18 20

0

100

200

300

400

500

600

Counts

U-component velocity, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

11.6

11.8

12.0

12.2

12.4

12.6

12.8

13.0

13.2

U-component velocity mean, m/s

Total number in the ensemble

 T140216

 T143550

 T144414

0 500 1000 1500 2000 2500 3000

1.4

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

U-component velocity standard deviation, m/s

Total number in the ensemble

 T140216

 T143550

 T144414

0 500 1000 1500 2000 2500 3000

-1.3

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

U-component velocity skew

Total number in the ensemble

 T140216

 T143550

 T144414

0 500 1000 1500 2000 2500 3000

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

U-component velocity excess

Total number in the ensemble

 T140216

 T143550

 T144414
Figure VI.26.- Convergence of the V-component velocity statistics and full ensemble histogram in the region 

directly behind the backward facing step (y/H = 0.0, x/H = 0.69).

VI.35

0.01

0.5

2

10

30

50

70

90

98

99.5

-8 -6 -4 -2 0 2 4 6

-8 -6 -4 -2 0 2 4 6

0

100

200

300

400

500

600

Counts

V-component velocity, m/s

CumulativeCounts

0 500 1000 1500 2000 2500 3000

-1.2

-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

 T140216

 T143550

 T144414

V-component velocity mean, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

 T140216

 T143550

 T144414

V-component velocity standard deviation, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

0.4

0.5

0.6

0.7

0.8

0.9

 T140216

 T143550

 T144414

V-component velocity skew

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

 T140216

 T143550

 T144414

V-component velocity excess

Total number in the ensemble
Figure VI.27.- Distribution of velocity magnitude for the individual data ensembles in the region directly behind 

the backward facing step (y/H = 0.0, x/H = 0.69).

VI.36

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16 18 20

0 2 4 6 8 10 12 14 16 18 20

0

50

100

150

200

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16 18 20

0 2 4 6 8 10 12 14 16 18 20

0

50

100

150

200

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16 18 20

0 2 4 6 8 10 12 14 16 18 20

0

50

100

150

200

Counts

Velocity magnitude, m/s

Cumulative Counts

D020410T140216 D020410T143550

D020410T144414
Figure VI.28.- Distribution of flow angle for the individual data ensembles in the region directly behind the 

backward facing step (y/H = 0.0, x/H = 0.69).

VI.37

D020410T140216 D020410T143550

D020410T144414

0.01

0.5

2

10

30

50

70

90

98

99.5

-30 -20 -10 0 10 20 30

-30 -20 -10 0 10 20 30

0

50

100

150

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-30 -20 -10 0 10 20 30

-30 -20 -10 0 10 20 30

0

50

100

150

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-30 -20 -10 0 10 20 30

-30 -20 -10 0 10 20 30

0

50

100

150

Counts

Flow angle, degrees

Cumulative Counts
Figure VI.29.- Distribution of U-component velocity for the individual data ensembles in the region directly behind 

the backward facing step (y/H = 0.0, x/H = 0.69).

VI.38

D020410T140216 D020410T143550

D020410T144414

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16 18 20

0 2 4 6 8 10 12 14 16 18 20

0

50

100

150

200

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16 18 20

0 2 4 6 8 10 12 14 16 18 20

0

50

100

150

200

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16 18 20

0 2 4 6 8 10 12 14 16 18 20

0

50

100

150

200

Counts

U-component velocity, m/s

Cumulative Counts
Figure VI.30.- Distribution of V-component velocity for the individual data ensembles in the region directly behind 

the backward facing step (y/H = 0.0, x/H = 0.69).

VI.39

D020410T140216 D020410T143550

D020410T144414

0.01

0.5

2

10

30

50

70

90

98

99.5

-8 -6 -4 -2 0 2 4 6

-8 -6 -4 -2 0 2 4 6

0

50

100

150

200

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-8 -6 -4 -2 0 2 4 6

-8 -6 -4 -2 0 2 4 6

0

50

100

150

200

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-8 -6 -4 -2 0 2 4 6

-8 -6 -4 -2 0 2 4 6

0

50

100

150

200

Counts

V-component velocity, m/s

Cumulative Counts
Figure VI.31.- Convergence of the velocity magnitude statistics and full ensemble histogram in the reverse flow 

region behind the backward facing step (y/H = -0.40, x/H = 0.69).

VI.40

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16

0 2 4 6 8 10 12 14 16

0

100

200

300

400

500

600

700

800

900

1000

Counts

Velocity magnitude, m/s

CumulativeCounts

0 500 1000 1500 2000 2500 3000

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

 T150434

 T151741

 T152942

Mean velocitymagnitude, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

1.0

1.1

1.2

1.3

1.4

1.5

1.6

 T150434

 T151741

 T152942

Velocity magnitude standarddeviation, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

0.3

0.4

0.5

0.6

0.7

0.8

 T150434

 T151741

 T152942

Velocitymagnitudeskew

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

 T150434

 T151741

 T152942

Velocitymagnitude excess

Total number in the ensemble
Figure VI.32.- Convergence of the flow angle statistics and full ensemble histogram in the reverse flow region 

behind the backward facing step (y/H = -0.40, x/H = 0.69).

VI.41

0.01

0.5

2

10

30

50

70

90

98

99.5

0 30 60 90 120 150 180 210 240 270 300 330 360

0 30 60 90 120 150 180 210 240 270 300 330 360

0

200

400

600

800

Counts

Flow angle, degrees

CumulativeCounts

0 500 1000 1500 2000 2500 3000

120

125

130

135

140

145

150

155

160

 T150434

 T151741

 T152942

Meanflow angle, degrees

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

30

35

40

45

50

55

60

65

70

75

 T150434

 T151741

Flow angle standard deviation, degrees

 T152942

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

 T150434

 T151741

 T152942

Flow angle skew

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

 T150434

 T151741

 T152942

Flow angleexcess

Total number in the ensemble
Figure VI.33.- Convergence of the U-component velocity statistics and full ensemble histogram in the reverse 

flow region behind the backward facing step (y/H = -0.40, x/H = 0.69).

VI.42

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2 4 6 8 10 12 14

-6 -4 -2 0 2 4 6 8 10 12 14

0

100

200

300

400

500

600

700

800

900

1000

Counts

U-component velocity, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

-2.4

-2.2

-2.0

-1.8

-1.6

-1.4

-1.2

-1.0

U-component velocity mean, m/s

Total number in the ensemble

 T150434

 T151741

 T152942

0 500 1000 1500 2000 2500 3000

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

U-component velocity standard deviation, m/s

Total number in the ensemble

 T150434

 T151741

 T152942

0 500 1000 1500 2000 2500 3000

-0.1

0.0

0.1

0.2

0.3

U-component velocity skew

Total number in the ensemble

 T150434

 T151741

 T152942

0 500 1000 1500 2000 2500 3000

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

U-component velocity excess

Total number in the ensemble

 T150434

 T151741

 T152942
Figure VI.34.- Convergence of the V-component velocity statistics and full ensemble histogram in the reverse 

flow region behind the backward facing step (y/H = -0.40, x/H = 0.69).

VI.43

0.01

0.5

2

10

30

50

70

90

98

99.5

-8 -6 -4 -2 0 2 4 6

-8 -6 -4 -2 0 2 4 6

0

100

200

300

400

500

600

700

800

900

1000

Counts

V-component velocity, m/s

CumulativeCounts

0 500 1000 1500 2000 2500 3000

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

 T150434

 T151741

 T152942

V-component velocity mean, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

0.9

1.0

1.1

1.2

1.3

1.4

1.5

 T150434

 T151741

 T152942

V-component velocity standard deviation, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

 T150434

 T151741

 T152942

V-component velocity skew

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

-1.0

-0.5

0.0

0.5

1.0

1.5

 T150434

 T151741

 T152942

V-component velocity excess

Total number in the ensemble
Figure VI.35.- Distribution of velocity magnitude for the individual data ensembles in the reverse flow region 

behind the backward facing step (y/H = -0.40, x/H = 0.69).

VI.44

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16

0 2 4 6 8 10 12 14 16

0

50

100

150

200

250

300

350

400

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16

0 2 4 6 8 10 12 14 16

0

50

100

150

200

250

300

350

400

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16

0 2 4 6 8 10 12 14 16

0

50

100

150

200

250

300

350

400

Counts

Velocity magnitude, m/s

Cumulative Counts

D020410T150434 D020410T151741

D020410T152942
Figure VI.36.- Distribution of flow angle for the individual data ensembles in the reverse flow region behind the 

backward facing step (y/H = -0.40, x/H = 0.69).

VI.45

0.01

0.5

2

10

30

50

70

90

98

99.5

0 30 60 90 120 150 180 210 240 270 300 330 360

0 30 60 90 120 150 180 210 240 270 300 330 360

0

50

100

150

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 30 60 90 120 150 180 210 240 270 300 330 360

0 30 60 90 120 150 180 210 240 270 300 330 360

0

50

100

150

Counts

Flow angle, degrees

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 30 60 90 120 150 180 210 240 270 300 330 360

0 30 60 90 120 150 180 210 240 270 300 330 360

0

50

100

150

Counts

Flow angle, degrees

Cumulative Counts

D020410T150434 D020410T151741

D020410T152942
Figure VI.37.- Distribution of U-component velocity for the individual data ensembles in the reverse flow region 

behind the backward facing step (y/H = -0.40, x/H = 0.69).

VI.46

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2 4 6 8 10 12 14

-6 -4 -2 0 2 4 6 8 10 12 14

0

50

100

150

200

250

300

350

400

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2 4 6 8 10 12 14

-6 -4 -2 0 2 4 6 8 10 12 14

0

50

100

150

200

250

300

350

400

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2 4 6 8 10 12 14

-6 -4 -2 0 2 4 6 8 10 12 14

0

50

100

150

200

250

300

350

400

Counts

U-component velocity, m/s

Cumulative Counts

D020410T150434 D020410T151741

D020410T152942
Figure VI.38.- Distribution of V-component velocity for the individual data ensembles in the reverse flow region 

behind the backward facing step (y/H = -0.40, x/H = 0.69).

VI.47

0.01

0.5

2

10

30

50

70

90

98

99.5

-8 -6 -4 -2 0 2 4 6

-8 -6 -4 -2 0 2 4 6

0

50

100

150

200

250

300

350

400

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-8 -6 -4 -2 0 2 4 6

-8 -6 -4 -2 0 2 4 6

0

50

100

150

200

250

300

350

400

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-8 -6 -4 -2 0 2 4 6

-8 -6 -4 -2 0 2 4 6

0

50

100

150

200

250

300

350

400

Counts

V-component velocity, m/s

Cumulative Counts

D020410T150434 D020410T151741

D020410T152942
Figure VI.39.- Convergence of the velocity magnitude statistics and full ensemble histogram in the shear flow 

region downstream from the backward facing step (y/H = -0.17, x/H = 1.37).

VI.48

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16

0 2 4 6 8 10 12 14 16

0

100

200

300

400

Counts

Velocity magnitude, m/s

CumulativeCounts

0 500 1000 1500 2000 2500 3000

5.0

5.5

6.0

6.5

7.0

7.5

8.0

 T153813

 T154726

 T155543

Mean velocity magnitude, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

1.8

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

 T153813

 T154726

 T155543

Velocity magnitude standarddeviation, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

0.1

0.2

0.3

0.4

0.5

 T153813

 T154726

 T155543

Velocity magnitudeskew

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

 T153813

 T154726

 T155543

Velocity magnitude excess

Total number in the ensemble
Figure VI.40.- Convergence of the flow angle statistics and full ensemble histogram in the shear flow region 

downstream from the backward facing step (y/H = -0.17, x/H = 1.37).

VI.49

0.01

0.5

2

10

30

50

70

90

98

99.5

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

200

400

600

800

1000

1200

Counts

Flow angle, degree

CumulativeCounts

0 500 1000 1500 2000 2500 3000

-10

-5

0

5

10

15

 T153813

 T154726

 T155543

Meanflow angle, degrees

Total number in the ensemble

0 500 1000 1500 2000 2500 3000 3500

0

10

20

30

40

50

60

 T153813

 T154726

Flowangle standard deviation, degrees

 T155543

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

 T153813

 T154726

 T155543

Flowangle skew

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

2

3

4

5

6

7

8

9

10

11

 T153813

 T154726

 T155543

Flow angleexcess

Total number in the ensemble
Figure VI.41.- Convergence of the U-component velocity statistics and full ensemble histogram in the shear flow 

region downstream from the backward facing step (y/H = -0.17, x/H = 1.37).

VI.50

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2 4 6 8 10 12 14

-6 -4 -2 0 2 4 6 8 10 12 14

0

100

200

300

400

Counts

U-component velocity, m/s

Cumulative Counts

0 500 1000 1500 2000 2500 3000

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

U-component velocity mean, m/s

Total number in the ensemble

 T153813

 T154726

 T155543

0 500 1000 1500 2000 2500 3000

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

U-component velocity standard deviation, m/s

Total number in the ensemble

 T153813

 T154726

 T155543

0 500 1000 1500 2000 2500 3000

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

U-component velocity excess

Total number in the ensemble

 T153813

 T154726

 T155543

0 500 1000 1500 2000 2500 3000

-0.4

-0.3

-0.2

-0.1

0.0

0.1

U-component velocity skew

Total number in the ensemble

 T153813

 T154726

 T155543
Figure VI.42.- Convergence of the V-component velocity statistics and full ensemble histogram in the shear flow 

region downstream from the backward facing step (y/H = -0.17, x/H = 1.37).

VI.51

0.01

0.5

2

10

30

50

70

90

98

99.5

-8 -6 -4 -2 0 2 4 6

-8 -6 -4 -2 0 2 4 6

0

100

200

300

400

Counts

V-component velocity, m/s

CumulativeCounts

0 500 1000 1500 2000 2500 3000

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

 T153813

 T154726

 T155543

V-component velocity mean, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

1.4

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

 T153813

 T154726

 T155543

V-component velocity standard deviation, m/s

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

 T153813

 T154726

 T155543

V-component velocity skew

Total number in the ensemble

0 500 1000 1500 2000 2500 3000

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

 T153813

 T154726

 T155543

V-component velocity excess

Total number in the ensemble
Figure VI.43.- Distribution of velocity magnitude for the individual data ensembles in the shear flow region 

downstream from the backward facing step (y/H = -0.17, x/H = 1.37).

VI.52

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16

0 2 4 6 8 10 12 14 16

0

50

100

150

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16

0 2 4 6 8 10 12 14 16

0

50

100

150

Counts

Velocity magnitude, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

0 2 4 6 8 10 12 14 16

0 2 4 6 8 10 12 14 16

0

50

100

150

Counts

Velocity magnitude, m/s

Cumulative Counts

D020410T153813 D020410T154726

D020410T155543
Figure VI.44.- Distribution of flow angle for the individual data ensembles in the shear flow region downstream 

from the backward facing step (y/H = -0.17, x/H = 1.37).

VI.53

0.01

0.5

2

10

30

50

70

90

98

99.5

-180-150 -120 -90 -60 -30 0 30 60 90 120 150 180

-180-150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

100

200

300

400

Counts

Flow angle, degree

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

100

200

300

400

Counts

Flow angle, degree

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-180-150 -120 -90 -60 -30 0 30 60 90 120 150 180

-180-150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

100

200

300

400

Counts

Flow angle, degree

Cumulative Counts

D020410T153813 D020410T154726

D020410T155543
Figure VI.45.- Distribution of U-component velocity for the individual data ensembles in the shear flow region 

downstream from the backward facing step (y/H = -0.17, x/H = 1.37).

VI.54

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2 4 6 8 10 12 14

-6 -4 -2 0 2 4 6 8 10 12 14

0

50

100

150

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2 4 6 8 10 12 14

-6 -4 -2 0 2 4 6 8 10 12 14

0

50

100

150

Counts

U-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-6 -4 -2 0 2 4 6 8 10 12 14

-6 -4 -2 0 2 4 6 8 10 12 14

0

50

100

150

Counts

U-component velocity, m/s

Cumulative Counts

D020410T153813 D020410T154726

D020410T155543
Figure VI.46.- Distribution of V-component velocity for the individual data ensembles in the shear flow region 

downstream from the backward facing step (y/H = -0.17, x/H = 1.37).

VI.55

0.01

0.5

2

10

30

50

70

90

98

99.5

-8 -6 -4 -2 0 2 4 6

-8 -6 -4 -2 0 2 4 6

0

50

100

150

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-8 -6 -4 -2 0 2 4 6

-8 -6 -4 -2 0 2 4 6

0

50

100

150

Counts

V-component velocity, m/s

Cumulative Counts

0.01

0.5

2

10

30

50

70

90

98

99.5

-8 -6 -4 -2 0 2 4 6

-8 -6 -4 -2 0 2 4 6

0

50

100

150

Counts

V-component velocity, m/s

Cumulative Counts

D020410T153813 D020410T154726

D020410T155543
Figure VI.47.- Velocity:data rate correlation coefficient and estimated flow correlation time as a function of 

position about the 3.5-inch and 1.5-inch backward facing steps in the BART.

VI.56

-0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5

-1.0

-0.5

0.0

0.5

3.5-inch Step H eight

 x/H = 0.32

 x/H = 0.43

 x/H = 0.69

 x/H = 0.90

 x/H = 1.11

 x/H = 1.37

Vertical distance, stepheight

Velocity:data rate correlation coefficient

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

-1.0

-0.5

0.0

0.5

1.5- inch Step H eight

 x/H = 0.75

 x/H = 0.80

 x/H = 1.05

 x/H = 1.30

 x/H = 1.60

Meanvelocity magnitude, m/s

Estimated flow correlation time, sec

-0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5

-1.0

-0.5

0.0

0.5

 x/H = 0.75

 x/H = 0.80

 x/H = 1.05 

 x/H = 1.30

 x/H = 1.60

Vertical distance, stepheight

Velocity:data rate correlation coefficient

1.5-inch Step H eight

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

-1.0

-0.5

0.0

0.5

3.5-inch Step H eight

 x/H = 0.32

 x/H = 0.43

 x/H = 0.69

 x/H = 0.90

 x/H = 1.11

 x/H = 1.37

Vertical distance, step height

Estimated flow correlation time, sec
Figure VI.48.- Comparison of U-component velocity measurements obtained with the upgraded laser velocimeter 

and the measurements obtained with the short focal length BART laser velocimeter at various stations 

downstream of the 1.5-inch backward facing step.

VI.57

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

BART LV

 BART LV: x/H = 0.53, fs = 45.0 m/s

 BART LV: x/H = 0.53, fs = 45.0 m/s

 BART LV: x/H = 0.53, fs = 45.0 m/s

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20

-1.0

-0.5

0.0

0.5

1.0

BART LV

 x/H = 0.53, fs = 45.0 m/s

 x/H = 0.53, fs = 45.0 m/s

 x/H = 0.53, fs = 45.0 m/s

Vertical distance, stepheight

U-component velocity standard deviation, σ /fs, percent

0 2 4 6 8 10 12 14 16 18

-1.0

-0.5

0.0

0.5

1.0

 BART LV: x/H = 0.53, fs = 45.0 m/s

 BART LV: x/H = 0.53, fs = 45.0 m/s

 BART LV: x/H = 0.53, fs = 45.0 m/s

 14x22 LV: x/H = 0.75, fs = 16.24 m/s

 14x22 LV: x/H = 0.80, fs = 16.24 m/s

Vertical distance, stepheight

U-component velocity standard deviation, σ /fs, percent

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 BART LV: x/H = 0.53, fs = 45.0 m/s 

 BART LV: x/H = 0.53, fs = 45.0 m/s

 BART LV: x/H = 0.53, fs = 45.0 m/s

 14x22 LV: x/H = 0.75, fs = 16.24 m/s

 14x22 LV: x/H = 0.80, fs = 16.24 m/s

Vertical distance, stepheight

U-component velocity mean, U/fs

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

14x22 LV

 x/H = 0.75 fs = 16.24 m/s

 x/H = 0.80 

 x/H = 1.05 

 x/H = 1.30 

 x/H = 1.60 

 x/H = 1.60 fs = 45.0 m/s

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20

-1.0

-0.5

0.0

0.5

1.0

 x/H = 0.75 fs = 16.24 m/s

 x/H = 0.80 

 x/H = 1.05 

 x/H = 1.30 

 x/H = 1.60 

 x/H = 1.60 fs = 45.0 m/s

Vertical distance, stepheight

U-component velocity standard deviation, σ /fs, percent 

14x22 LV
Figure VI.49.- Comparison of U-component velocity measurements obtained with the upgraded laser velocimeter 

and the measurements obtained using a short focal length laser velocimeter in the BART at various stations 

downstream of the backward facing step.

VI.58

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

14x22 LV

1.5-inch Step

 x/H = 0.75 fs = 16.24 m/s

 x/H = 0.80 

 x/H = 1.05 

 x/H = 1.30 

 x/H = 1.60 

 x/H = 1.60 fs = 45.0 m/s

Vertical distance, stepheight

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20

-1.0

-0.5

0.0

0.5

1.0

 x/H = 0.75 fs = 16.24 m/s

 x/H = 0.80 

 x/H = 1.05 

 x/H = 1.30 

 x/H = 1.60 

 x/H = 1.60 fs = 45.0 m/s

Vertical distance, step height

U-component velocity standard deviation, σ /fs, percent 

14x22 LV

1.5-inch Step

0 2 4 6 8 10 12 14 16 18 20

-1.0

-0.5

0.0

0.5

1.0

BART LV

1.5-inch Step

 x/H = 0.53, fs = 45.0 m/s

 x/H = 0.53, 

 x/H = 0.53, 

 x/H = 6.64, 

 x/H = 6.64, 

Vertical distance, step height

U-component standard deviation, σ /fs, percent

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

BART LV

1.5-inch Step

 x/H = 0.53, fs = 45.0 m/s

 x/H = 0.53, 

 x/H = 0.53, 

 x/H = 6.64, 

 x/H = 6.64, 

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20

-1.0

-0.5

0.0

0.5

1.0

 x/H = 0.32 fs = 16.24 m/s

 x/H = 0.43 

 x/H = 0.69 

 x/H = 0.90 

 x/H = 1.11 

 x/H = 1.37 

Vertical distance, stepheight

U-component velocity standard deviation, σ /fs, percent 

14x22 LV

3.5-inch Step

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

14x22 LV

3.5 inch Step

 x/H = 0.32 fs = 16.24 m/s

 x/H = 0.43 

 x/H = 0.69 

 x/H = 0.90 

 x/H = 1.11 

 x/H = 1.37 

Vertical distance, step height

U-component velocity mean, U/fs
Figure VI.49 (cont'd).- Comparison of U-component velocity measurements obtained with the upgraded laser 

velocimeter and the measurements obtained using a short focal length laser velocimeter in the BART at various 

stations downstream of the backward facing step.

Figure VI.50.- Schematic of the channel flow generator with an internal backward facing step, and the schematic 

of the three-component, three-color laser velocimeter.

VI.59

0 5 10 15 20

-1.0

-0.5

0.0

0.5

Vertical distance, stepheight

U-component velocity standard deviation, percent

 x/H = 0.53 45.0 m/s fs

 x/H = 0.53 |

 x/H = 0.53 V

Short focal length

1.5-inch step

 x/H = 0.43

 x/H = 0.69

Long focal length

fs = 16.6 m/s

3.5-inch step

 x/H = 0.75 16.24 m/s fs

Long focal length

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

Vertical distance, stepheight

U-component velocity mean, U/fs

 x/H = 0.53 45.0 m/s fs

 x/H = 0.53 |

 x/H = 0.53 V

Short focal length

1.5-inch step

 x/H = 0.43

 x/H = 0.69

Long focal length

fs = 16.6 m/s

3.5-inch step

 x/H = 0.75 16.24 m/s fs

Long focal length

Honeycomb

48" 48"

6"

Flow 3"

Screens

}
Figure VI.51.- Photograph of the channel flow generator with the internal backward facing step along with the 

three-component laser velocimeter installed about the channel.

Figure VI.52.- U-component velocity maps of the flow about the backward facing step embedded within the 

channel flow generator.

VI.60

0 .2 .4 .6 .8 1.0

U-component mean velocity, U/fs

0 4 8 12 16 20 24

Axial distance, in

3

2

1

0

-1

-2

-3

H eig ht, in

6 9 12 15 18 21

U-component velocity standard deviation, percent

0 4 8 12 16 20 24

Axial distance, in

3

2

1

0

-1

-2

-3

Height, in
Figure VI.53.- Comparison of U-component velocity measurements obtained with the upgraded laser velocimeter 

and the measurements obtained using a short focal length laser velocimeter in a channel at various stations 

downstream of the backward facing step.

VI.61

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

 x/H = 0.667 50.0 m/s fs

 x/H = 0.883 |

 x/H = 1.0 |

 x/H = 1.167 |

 x/H = 1.333 |

 x/H = 1.5 V

Vertical distance, stepheight

U-component velocity mean, U/fs

0 5 10 15 20

-1.0

-0.5

0.0

0.5

 x/H = 0.667 50.0 m/s fs

 x/H = 0.833 |

 x/H = 1.0 |

 x/H = 1.167 |

 x/H = 1.333 |

 x/H = 1.5 V

Vertical distance, stepheight

U-component velocity standard deviation, percent

0 2 4 6 8 10 12 14 16 18 20

-1.0

-0.5

0.0

0.5

 x/H = 0.32

 x/H = 0.43

 x/H = 0.69

 x/H = 0.90

 x/H = 1.11

 x/H = 1.37

Vertical distance, stepheight

U-component velocity standard deviation, percent

fs = 16.6 m/s

step height = 3.5 inches

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

 x/H = 0.32

 x/H = 0.43

 x/H = 0.69

 x/H = 0.90

 x/H = 1.11

 x/H = 1.37

Vertical distance, stepheight

U-component mean velocity, U/fs

fs = 16.6 m/s

step height = 3.5 inches

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

 x/H = -0.333 50.0 m/s fs

 x/H = -0.167 |

 x/H = 0.0 |

 x/H = 0.167 |

 x/H = 0.333 |

 x/H = 0.5 V

Vertical distance, stepheight

U-component velocity mean, U/fs

0 5 10 15 20

-1.0

-0.5

0.0

0.5

 x/H = -0.333 50.0 m/s fs

 x/H = -0.167 |

 x/H = 0.0 |

 x/H = 0.167 |

 x/H = 0.333 |

 x/H = 0.5 V

Vertical distance, stepheight

U-component velocity standard deviation, percent
Figure VI.53 (cont'd).- Comparison of U-component velocity measurements obtained with the upgraded laser 

velocimeter and the measurements obtained using a short focal length laser velocimeter in a channel at various 

stations downstream of the backward facing step.

VI.62

0 5 10 15 20

-1.0

-0.5

0.0

0.5

Vertical distance, stepheight

U-component velocity standard deviation, percent

 x/H = 0.69 16.6 m/s fs

 x/H = 0.90 16.6 m/s fs

 x/H = 0.667 50.0 m/s fs

 x/H = 0.833 50.0 m/s fs

Channel Flow Step

BART

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

Vertical distance, stepheight

U-component velocity mean, U/fs

 x/H = 0.69 16.6 m/s fs

 x/H = 0.90 16.6 m/s fs

 x/H = 0.667 50.0 m/s fs

 x/H = 0.833 50.0 m/s fs

Channel Flow Step

BART

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

Vertical distance, stepheight

U-component velocity mean, U/fs

Channel Flow Step

BART

 x/H = 1.167 50.0 m/s fs

 x/H = 1.333 50.0 m/s fs

 x/H = 1.11 16.6 m/s fs

 x/H = 1.37 16.6 m/s fs

0 5 10 15 20

-1.0

-0.5

0.0

0.5

Vertical distance, stepheight

U-component velocity standard deviation, percent

Channel Flow Step

BART

 x/H = 1.167 50.0 m/s fs

 x/H = 1.333 50.0 m/s fs

 x/H = 1.11 16.6 m/s fs

 x/H = 1.37 16.6 m/s fs

0 5 10 15 20

-1.0

-0.5

0.0

0.5

Vertical distance, stepheight

U-component velocity standard deviation, percent

 x/H = 0.333 50.0 m/s fs

 x/H = 0.5 50.0 m/s fs

 x/H = 0.32 16.6 m/s

 x/H = 0.43 16.6 m/s

Channel Flow Step

BART

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

Vertical distance, stepheight

U-component velocity mean, U/fs

 x/H = 0.333 50.0 m/s fs

 x/H = 0.5 50.0 m/s fs

 x/H = 0.32 16.6 m/s

 x/H = 0.43 16.6 m/s

Channel Flow Step

BART
Figure VI.54.- Theoretical signal level distributions from 1.7-micron PSL particles along with the measurement 

distribution obtained from latex particles exiting the Royco particle generator.

Figure VI.55.- Distributions of signal level obtained from the upgraded laser velocimeter using two sizes of PSL 

particles injected in the BART with a paint sprayer.

VI.63

0.0 0.2 0.4 0.6 0.8 1.0

0

500

1000

1500

2000

N umber of occurrences

Signal level - peak = 1.0

 Theoretical

Average = 0.098

StDev = 0.132

Skew = 2.659

Median = 0.05

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Numberof occurances

Signal amplitude, V

 V-component

 h/H = 0.4

Particle Size = 0.68 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Numberof occurances

Signal amplitude, V

 U-component

Particle Size = 0.68 microns

 U V

Average 0.055 0.042

StDev 0.037 0.029

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

1000

Number of occurances

Signal amplitude, V

 V-component

 h/H = 0.4

Particle Size = 1.7 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

1000

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 1.7 microns

 U V

Average 0.166 0.033

StDev 0.055 0.019

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Number of occurances

Signal amplitude, V

 V-component

 h/H = 0.3

Particle Size = 0.68 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 0.68 microns

 U V

Average 0.053 0.043

StDev 0.046 0.035

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

Number of occurances

Signal amplitude, V

 V-component

 h/H = 0.3

Particle Size = 1.7 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 1.7 microns

 U V

Average 0.166 0.035

StDev 0.055 0.025

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

50

100

150

200

250

300

Number of occurrences

Signal amplitude, V

 U-component

D010810T114650

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

50

100

150

200

250

300

Number of occurrences

Signal amplitude, V

 V-component

 U V

Average 0.057 0.043

StDev 0.023 0.020

Old Particles - 1.9 Microns

Royco
Figure VI.55 (cont'd).- Distributions of signal level obtained from the upgraded laser velocimeter using two sizes 

of PSL particles injected in the BART with a paint sprayer.

VI.64

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Number of occurances

Signal amplitude, V

 V-component

 h/H = 0.2

Particle Size = 0.68 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 0.68 microns

 U V

Average 0.049 0.039

StDev 0.033 0.025

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

1000

Number of occurances

Signal amplitude, V

 V-component

 h/H = 0.2

Particle Size = 1.7 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

1000

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 1.7 microns

 U V

Average 0.171 0.037

StDev 0.055 0.020

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Numberof occurances

Signal amplitude, V

 V-component

 h/H = 0.1

Particle Size = 0.68 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Numberof occurances

Signal amplitude, V

 U-component

Particle Size = 0.68 microns

 U V

Average 0.052 0.036

StDev 0.032 0.018

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

Number of occurances

Signal amplitude, V

 V-component

 h/H = 0.1

Particle Size = 1.7 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 1.7 microns

 U V

Average 0.172 0.027

StDev 0.052 0.009

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Numberof occurances

Signal amplitude, V

 V-component

 h/H = 0.0

Particle Size = 0.68 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Numberof occurances

Signal amplitude, V

 U-component

Particle Size = 0.68 microns

 U V

Average 0.049 0.040

StDev 0.033 0.024

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

Number of occurances

Signal amplitude, V

 V-component

 h/H = 0.0

Particle Size = 1.7 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 1.7 microns

 U V

Average 0.126 0.032

StDev 0.054 0.015
Figure VI.55 (cont'd).- Distributions of signal level obtained from the upgraded laser velocimeter using two sizes 

of PSL particles injected in the BART with a paint sprayer.

VI.65

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

Number of occurances

Signal amplitude, V

 V-component

 h/H = -0.2

Particle Size = 0.68 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 0.68 microns

 U V

Average 0.038 0.037

StDev 0.012 0.019

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

Number of occurances

Signal amplitude, V

 V-component

 h/H = -0.2

Particle Size = 1.7 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 1.7 microns

 U V

Average 0.092 0.032

StDev 0.032 0.013

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Number of occurances

Signal amplitude, V

 V-component

 h/H = -0.3

Particle Size = 0.68 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 0.68 microns

 U V

Average 0.027 0.030

StDev 0.012 0.016

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

1000

1100

Number of occurances

Signal amplitude, V

 V-component

 h/H = -0.3

Particle Size = 1.7 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

1000

1100

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 1.7 microns

 U V

Average 0.074 0.027

StDev 0.022 0.014

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Numberof occurances

Signal amplitude, V

 V-component

 h/H = -0.4

Particle Size = 0.68 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Numberof occurances

Signal amplitude, V

 U-component

Particle Size = 0.68 microns

 U V

Average 0.029 0.029

StDev 0.011 0.013

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

Number of occurances

Signal amplitude, V

 V-component

 h/H = -0.4

Particle Size = 1.7 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 1.7 microns

 U V

Average 0.066 0.025

StDev 0.015 0.012
Figure VI.55 (cont'd).- Distributions of signal level obtained from the upgraded laser velocimeter using two sizes 

of PSL particles injected in the BART with a paint sprayer.

VI.66

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Number of occurances

Signal amplitude, V

 V-component

 h/H = -0.47

Particle Size = 0.68 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 0.68 microns

 U V

Average 0.031 0.031

StDev 0.008 0.020

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

Number of occurances

Signal amplitude, V

 V-component

 h/H = -0.47

Particle Size = 1.7 microns

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

Number of occurances

Signal amplitude, V

 U-component

Particle Size = 1.7 microns

 U V

Average 0.064 0.023

StDev 0.013 0.007
Testing the Upgraded 

14- by 22-Foot Subsonic Tunnel Laser Velocimeter

Phase II

The two issues found during the risk reduction test in BART were the length of time 

needed to transfer the data from the data acquisition computer memory to the hard drives 

on the two computers, and the false data triggers traced to spurious noise spikes produced 

by the photomultiplier. The time required to transfer the measurement data was reduced 

by writing a multi-thread C-program to transfer the data in binary format to the disk 

drives. Previously it took approximately 77-seconds to store 1,000 measurements whereas 

the C-program reduced the time to 8.8-seconds. A measurement consisted of 10,000 

floating point samples of the U- and V-component amplitudes along with the clock time 

trace. Additionally a header was attached that included, for example, the measurement 

location, inter-arrival time, azimuth angle, and conditionally sampled signal readings.

The false triggers were eliminated through the development of a signal identification 

circuit. The false triggers were found to have a high amplitude spike followed by a few low 

amplitude oscillations, most likely caused by ringing in the filtering circuits in the TSI 

electronics, whereas a signal burst generated by a particle passage through the LV 

measurement volume contained numerous oscillations. Using these characteristics a 

circuit was developed that, once triggered by the oscilloscope external trigger, would count 

positive zero crossings. Only if the number of zero crossings was greater than eight, a 

trigger pulse would be generated to command the high-speed analog-to-digital converter 

(ADC) to capture the signal burst. The pretrigger capabilities of the ADC insured that the 

entire signal burst would be captured, thus negating any time delay imposed by the signal 

identification circuit.

An auxiliary display program was developed to provide a running display of the results as 

the measurement volume was scanned through the flow field. The program provides 

profiles of the U- and V-component results along with velocity magnitude and flow angle. 

Each profile contains the means and standard deviations along with error bars based on 

statistical uncertainty for each of the four measurements. The plots update automatically 

as each new ensemble is processed.

The investigations also afforded the opportunity to determine whether particles smaller 

than the 1.7-micron PSL particles used previously could provide signals with sufficient 

amplitudes and signal-to-noise ratios to yield accurate velocity measurements.

Laboratory Investigation

A laboratory investigation was conducted to determine if the improvements to the laser 

velocimeter corrected the issues found in the BART test. The investigation was conducted 

under production conditions by measuring vertical velocity profiles at the flow centerline of 

the jet exiting the 50-mm diameter jet flow apparatus. A profile consisted of a series of 

VII.1
measurements made every 2.5-mm across the diameter of the jet cross section to yield 

profiles containing up to 38 measurement locations. Signal traces from 1000 signal bursts 

were processed at each measurement location. If statistical stationarity was not found, 

based on the real time plots of velocity/standard as a function of number of measurements, 

additional measurement ensembles were acquired at that location until stationarity was 

reached. The signal/data processing program was modified to automatically combine the 

repeated ensembles with the original ensemble to process the entire data set at that 

location. Status data based on the average of the standard deviations of the last five means 

for each of the four measurements (U- and V-components, velocity magnitude and flow 

angle) were returned to the data acquisition program for comparison with the user selected 

threshold that would indicate flow statistical stationarity. If the average standard 

deviation was larger than the threshold value, an alert was presented to the user by the 

data acquisition program suggesting that another data ensemble should be acquired.

The laser velocimeter was configured to a focal distance of 5.0 meters to approximate the 

focal distance to the centerline of the 14- by 22-Foot Subsonic Tunnel. A folding mirror 

was used to direct the optical axis orthogonal to the centerline of the jet flow to measure 

the streamwise and vertical velocity components. The vertical measurement profile was 

obtained by moving the optical system with a mechanical traversing mechanism. The laser 

power was set to 1.0-W, all-lines. A single Laskin nozzle was used to inject 1.0-micron PSL 

particles into the inlet of the squirrel-cage fan used to drive the flow apparatus. The 

average high-pass filtered signal output was ±0.6 V with a data rate of 207 acceptable 

signal bursts per second at 0.125-inch downstream of the jet exit. The rate dropped to 44 

and 131 acceptable signal bursts per second at the ±1.0 radii locations respectively. At two 

jet diameters downstream, the centerline data rate dropped to 10 acceptable signal bursts 

per second. The peak signal values had a standard deviation of 0.2 V in all cases. This 

indicated that all of the water:ethanol carrier had evaporated, and that the Gaussian 

characteristics of the laser power throughout the measurement volume cross section were 

maintained.

Vertical scans were obtained at six downstream stations, Figure VII.1. These data sets 

were acquired and processed during a five hour test session. A repeatability test was 

conducted at the 10.25-inch downstream location, Figure VII.2. As shown in Figure VII.2, 

the two data sets are virtually identical not only in mean and standard deviation, but in 

skew and excess. During the acquisition phase, a uniform random number generator was 

used to obtain a synthetic “azimuth” angle for each signal burst that was processed. Since 

a uniform random number was used, the resulting statistics plotted as a function of 

“azimuth” should have the same value within the bounds of statistical uncertainty. This 

was found to be the case for all of the statistical calculations, Figure VII.3.

The laboratory investigation showed that the system upgrades provided acquisition rates 

that would satisfy production requirements, and that there were no acquisitions from noise 

spikes originating from the photomultiplier. Further the signal levels obtained from 

1.0-micron PSL particles were sufficient to yield results that were comparable to those 

VII.2
from the larger particles. However, the velocity measurements should be more accurate 

based on the ability of the smaller particles to track the flow field with better fidelity.

Basic Aerodynamic Research Tunnel

Backward-facing Step

The laser velocimeter system was installed in the BART with the same configuration used 

in the first backward-facing step investigation, Chapter VI. For this entry, the 1.5-inch 

step model was installed first with the flow conditions set to match the conditions used to 

obtain the validation laser velocimetry measurements (Hart et al (2001)), Figure VI.48. 

Several additional vertical profiles were obtained beside the matching profile at x/H = 53 

downstream of the step to determine if the data from the current investigation yielded a 

reasonable description of the flow field. The second investigation was the flow about the 

3.5-inch backward-facing step. Instead of repeating the previous LV measurement 

locations from Chapter VI, the locations were extrapolated based on step height from the 

smaller step, and the test conditions fixed to the same settings as used with the smaller 

step. This would provide a direct comparison of measurements to determine if the two 

flow fields had similar characteristics.

1.5-inch backward facing step

A series of vertical profiles was obtained at downstream stations beginning at x/H = 0.262 

with increments of 0.262 x/H to nominally x/H = 4.0 to obtain a grid mapping of the flow 

downstream of the backward-facing step. The series of velocity profiles for the U- and Vcomponents is shown in Figure VII.4. The plots include mean and standard deviation of 

the two velocity components along with the number of validated measurements within the 

ensemble and the levels of convergence for those ensembles. The U-component mean and 

standard deviation profiles obtained from the BART laser velocimeter, Figure VI.48., is 

overlaid for comparison. The comparison of the profiles at the same downstream location, 

Figure VII.4.b., shows almost identical results. Thus the measurements obtained by the 

upgraded laser velocimeter have been shown to be of sufficient accuracy for wind tunnel 

applications. By plotting the data as a function of downstream location, Figure VII.5, the 

boundary of the separated flow can be found. For example, near the step at z/H = 0.050, 

(Figure VII.5.d.) the effects of the step can be seen with the drop in velocity even though 

the location is above the step. At z/H = -0.090, Figure VII.5.e., the velocity has dropped to 

nearly 0.0 U/fs, and at z/H = -0.220, Figure VII.5.f., the U-component velocity has become 

negative. Finally at z/H = -0.755, Figure VII.5.k., the entire profile is negative.

The flow characteristics can be viewed in another way by computing the velocity 

magnitude and flow angle statistics, Figures VII.6 (vertical scans) and VII.7 (horizontal 

scans). This is possible since the data processing software can extract the coincident Uand V-component measurements from the data ensembles. While the velocity magnitude 

basically tracks the characteristics of the U-component velocity until the flow reverses, the 

flow angle provides a bit more insight into the flow characteristics. The flow reversal point 

has a very strong demarcation with an associated strong spike in standard deviation. The 

VII.3
vertical scan at the 0.525 x/H station, Figure VII.6.b, indicates that the measurement 

volume went below the rotational flow since the mean flow angle was no longer reversed, 

and may even indicate the entrance into the secondary vortex. However at stations close 

to the step, the standard deviations in flow angle reached up to 100-degrees. Moving 

further downstream a spike in the standard deviation developed at the reversal point. The 

high standard deviations began to fall near the floor at the 1.050 x/H station, Figure 

VII.6.d, and continued to fall further downstream, reaching 30-degrees at the 2.362 x/H 

station, Figure VII.6.i. The standard deviation near the floor rose again further 

downstream as the spike moved closer to the floor. These characteristics form a clear trend 

in the horizontal plots, Figure VII.7, showing the reversal point moving downstream as the 

floor is approached, with the maximum standard deviation tracking the reversal.

Although the current measurements are nearly identical to the reference measurements 

obtain by the dedicated laser velocimeter in BART, there is still a concern about sampling 

bias affecting the accuracy of the measurements. Edwards and Meyers (1984) showed that 

sampling bias could be corrected if the data rate was higher than the integral time scale of 

the flow at the measurement location. However, the current data acquisition system has 

reset times greater than typical flow integral time scales. Thus each measurement is 

independent of the previous measurements and correction is not necessary or possible. 

However, the probability that the freestream will contribute more particles, and thus more 

measurements, than the recirculation flow will still produce sampling bias as the two flow 

states randomly switch at a given measurement location within the shear region. 

Therefore it is concluded that uncorrectable sampling bias exists in the measurements 

obtained within the shear region. 

The improvements in the LV data acquisition and signal/data processing software had no 

apparent effect on the characteristics of the velocity standard deviation trends found in the 

first investigation in BART, Figures VII.4-VII.5 and VI.48-VI.49. Applying the same test 

used to determine if statistical stationarity had been reached described above during 

laboratory testing, the number of measurements required remained fairly constant until 

the recirculation zone was entered, Figures VII.4 and VII.5. In general the average 

standard deviations, used as the test for statistical stationarity as described above, were 

less than 0.02 m/s outside recirculation. Within the region the average standard deviation 

reached 0.07 m/s, primarily because of the lack of acceptable signals within the vortex. 

These trends, however, provided no insight into the large standard deviations found below 

the shear region since the statistical uncertainties of the standard deviation measurements 

were relatively small.

Skewness of the velocity distributions should not only be an indicator of the amount of 

time the freestream flow is present versus the recirculation flow at a given location, but 

also an indicator of sampling bias. If the measurement location is in freestream, there 

should be no contribution from the recirculation flow resulting in a skew near zero. As the 

measurement location is lowered into the shear region, a small contribution from the 

recirculation region should be present affecting the skew results. Particle seeding should 

follow the same pattern, with the majority of the particles found in the freestream 

VII.4
segments, not only because of the greater presence of the freestream flow, but its increased 

seeding density as compared to the recirculation region. This should produce a skew of the 

velocity distribution toward the higher velocities. With the measurement location in the 

center of the shear region, the percentage of time the flow originates from freestream is 

equal to the percentage from the recirculation. However, the particle number density 

distribution will cause the freestream flow to be over sampled as compared to the 

recirculation. Again this would result in a smaller, but still positive skew instead of the 

actual near zero skew that would be expected. Finally, at the lower extent of the shear 

region, the primary contributor would be the recirculation flow which should produce a 

negative skew, although sampling bias could lessen the amount of skew even to zero. Once 

within the core of the recirculation region, the levels of skew should be near zero as the 

velocity gradient is linear through the measurement volume diameter. The effects of 

sampling bias, if any, would be unknown within the recirculation region.

From the trends shown in Figure VII.8, the U-component had a fairly strong negative skew 

in freestream while the V-component had a fairly positive skew. Inspecting the traces 

further downstream of the step, the U-component developed a strong negative peak in 

skew just above the step height, while the V-component developed a strong negative peak 

in skew below the step height. At approximately three step heights downstream, the peak 

in the V-component disappeared while the U-component peak continued although falling 

below the step height. These trends continued further downstream. The streamwise 

profiles of component skew, Figure VII.9, were fairly random with no indication of the 

sharp shifts in skew found in the vertical traces. However, there was a sharp shift in flow 

angle skew that translated downstream. The shift is first found at a height of 0.090 z/H, 

Figure VII.9.e, below the step just downstream of the step. The shift continued 

downstream until a height of -0.606 z/H, Figure VII.9.j, is reached when the artifact moves 

downstream of the interrogation region.

The Reynolds stress traces in the streamwise direction, Figure VII.9, have a significant 

change from a measurement height of 0.050 z/H to -0.090 z/H, Figures VII.9.d and VII.9.e, 

respectively. This artifact moves downstream becoming narrower and stronger as the 

height above the floor is reduced. The vertical scans of Reynolds stress, Figure VII.8, show 

a sharp negative stress artifact at the step height for a downstream location of 0.262 x/H, 

Figure VII.8.a. This artifact grows stronger while dropping in height as the measurement 

location is moved downstream. These results appear to show that the artifact in the 

Reynolds stress measurements is an indicator of the center of the shear region. The 

artifact appeared to have the same location profile as found with the flow angle standard 

deviation peak locations, Figure VII.6.

3.5-inch backward facing step

After the model change to a 3.5-inch backward facing step, a repeat investigation was 

conducted with the measurement locations selected to scale with step height, matching the 

equivalent locations measured downstream of the 1.5-inch step. The size of the step, 

VII.5
however, limited the number of locations that could be measured because of beam blocking 

by the model and the equivalent reduction in traversing range.

The results, shown in Figures VII.10-VII.13, U-and V-component velocities (vertical and 

streamwise scans) and Magnitude and Flow Angle (vertical and streamwise scans) 

respectively, have similar characteristics found in the results from the 1.5-inch step. The 

component standard deviations also remained elevated below the shear region. The 

characteristics found in the skew results and the Reynolds stress found in the 1.5-inch step 

investigation were also found in the 3.5-inch step study, Figures VII.14 and VII.15.

Comparison as normalized by step height

In order to obtain a better visual comparison, the results from both LV investigations were 

scaled by step height and plotted in Figures VII.16 - VII.18 (vertical scans), and VII.19 - 

VII.21 (streamwise scans). From the comparison of the U-component measurements in 

Figure VII.16, it was found that the velocity above the 3.5-inch step was slightly higher 

than above the 1.5-inch step. Also the flow had a greater negative velocity in the 

separation region below the 3.5-inch step. However the characteristics of the U-component 

standard deviations were almost identical except the peak in the standard deviation grew 

in strength and width at further downstream locations from the 3.5-inch step. These 

characteristics were also found in the V-component measurements except that the mean 

measurements were consistently higher about the 3.5-inch step.

The characteristics of the velocity magnitude found in Figure VII.17 were similar to those 

found in the U-component measurements. However, the flow angle measurements had 

some differences, especially in standard deviation. It appears that the shear region is 

slightly higher downstream of the 3.5-inch step. Further the standard deviation of flow 

angle is consistently higher below the shear region for the 1.5-inch step. Measurements of 

skew shown in Figure VII.18 are loosely similar, but there is a great deal of randomness in 

the results. However, the Reynolds stress measurements are virtually identical except for 

the greater stress values obtained in the shear region further downstream of the 3.5-inch 

step.

Plotting the data as a function of downstream location at fixed heights above the floor 

appear to remove much of the randomness in the data. Here in Figures VII.19 – VII.21, 

the similarities and differences between the measurements are clearly seen. Overall the 

data show consistent patterns indicating that the they represent reasonable indicators of 

the true flow field. The differences between the two steps may be attributed to Reynolds 

number effects – we leave this conclusion to the Aerodynamicists. 

Flow measurements downstream of a NACA 0012 airfoil

Since one of the prime flow structures to be investigated is the rotor tip vortex, it seemed 

appropriate to determine if the measurement volume length would compromise the 

measurements of a vortical flow. Thus the backward-facing step was removed from the 

VII.6
test section and a NACA 0012 airfoil was installed on the floor of the test section which 

placed the wing tip near the test section centerline. The model could be manually rotated 

to select the angle-of-attack. Three tests were conducted: 1) stable vortex flow with the 

wing set to an 8.0-degree angle-of-attack; 2) burst vortex with the wing angle-of-attack set 

to 20.0-degrees; and, 3) an investigation of the wake region with the wing returned to an 

8.0-degree angle-of-attack. In each case the measurement volume was scanned across the 

test section, orthogonal to the wing span.

Measurements of the vortex generated by the airfoil set to 8.0-degrees angle-of-attack were 

conducted on three successive days, Figure VII.22.a. The three U-component velocity 

profiles were virtually identical. They showed a slight change in velocity along the scan 

plus the characteristic deficit found within the vortex. The standard deviation 

measurements remained low and repeatable throughout the profile. The V-component 

velocity profiles were also virtually identical with the characteristic shape expected from 

the radial spin found in a stable vortex. The significant peak in the standard deviation at 

the vortex core shows the effect of the finite size of the measurement volume. Unlike other 

techniques that average the flow over the measurement volume, classic laser velocimetry 

measures each particle velocity within the volume, but can not determine its location 

within the volume. For example, if the volume extends through a velocity gradient, as in 

the case of the vortex core, high-speed particles may be measured at one end of the volume 

and low-speed particles at the other. The calculation of the mean velocity will basically 

negate the differences, but the standard deviation will be very high caused by the velocity 

gradient, not turbulence. If the measurement volume was infinitely small, the standard 

deviation would not measure the gradient effects, but just the turbulence in the flow. 

While the V-component results indicate that the size of the measurement volume is 

affecting the measurement accuracy, a better indicator is the profile of the flow angle, 

Figure VII.23.a. Ideally the flow angle profile should swing ±90-degrees (assuming that 

the scan is through the exact center of the vortex), but the measurements indicate only a 

swing of ±20-degrees. This means that either the scan was not through the center of the 

vortex, or that the length of the measurement volume has spatially low-pass filtered the 

flow gradient, or both. Here again the peak in the standard deviation of upwards of 

8-degrees indicate the averaging effects typical of laser velocimetry. However, considering 

the focal distance, the measurement volume effects appear to be less than expected for a 

vortex core approximately 0.4-inches in diameter.

The airfoil angle-of-attack was then increased to 20.0-degrees to establish a burst vortex. 

The results from the U- and V-component measurements, along with a repeat of one of the 

profiles obtained at 8.0-degrees for reference, are shown in Figure VII.22.b. The results 

show that the vortex has moved from approximately 0.5-inches below the wing, to 

2.0-inches above the wing. The U-component profiles show a significant deficit in velocity 

with an associated increase in standard deviation (15-percent of the local mean velocity). 

The V-component profiles show a less sharp vortical profile with an increase in standard 

deviation far greater than can be attributed to gradient effects. The velocity magnitude 

and flow angle profiles, Figure VII.23.b, are very similar to the U- and V-component 

profiles, respectively. Here the flow angle standard deviation peaks at 12-degrees. Based 

VII.7
on these measurements, one would conclude that the flow in a burst vortex was very 

turbulent. However, measurements made using Doppler global velocimetry of a burst 

vortex generated by a delta wing at high angle-of-attack (Meyers et al (1994)) showed the 

cross-flow mapping of a solid body of revolution with only small scale turbulence, not the 

massive turbulence indicated by, for example, laser light sheet visualization. Each 

captured frame (1/60 of a second) showed the mapping of a solid body of revolution, except 

that the average velocity varied considerably from frame to frame. Thus a burst vortex is 

structured in space with a large variation in velocity with time which gives rise to the large 

standard deviations measured by the laser velocimeter.

The investigation of the wake region with the wing set at 8-degrees angle-of-attack, found 

the small deficit (5-percent) in the streamwise velocity in the wake centered about an inch 

above the wing, Figure VII.22.c. There was an accompanying small rise in standard 

deviation. The V-component showed only a slight rise in velocity from negative in-board to 

positive out-board. The extent of the rise was approximately the same as the width of the 

deficit found in the U-component. Again there was only a small increase in standard 

deviation at the wake. These same characteristics were found in the velocity magnitude 

and flow angle, Figure VII.23.c, respectively.

The measurements of velocity skew and flow angle skew, Figure VII.24, appear to have 

some structure, but there is considerable noise in the profiles not found in the backwardfacing step investigations. The reason for these large excursions in skew is unknown, but 

they do not originate from statistical uncertainty attributed to small data ensembles as the 

number of accepted signal bursts, Figure VII.22, was over 98-percent of bursts generating 

triggers. On the other hand, the Reynolds stress profiles distinct structures occurring at 

the vortices. A profile similar to that shown by the U-component mean in Figure VII.22.a 

was found at the vortex location with the wing set to 8.0-degrees angle-of-attack, 

Figure VII.24.a. When the angle-of-attack was increased to 20.0-degrees, the Reynolds 

stress profile, Figure VII.24.b, had the shape of the V-component mean in Figure VII.22.a. 

Finally, there was absolutely no stress measured in the cross-flow profile through the wake 

region, Figure VII.24.c. The significance of these results are left for the Aerodynamicists 

to determine.

BART test summary

To summarize the results from the investigations conducted in BART, the laser velocimeter 

performed in a manner acceptable for production testing in the 14- by 22-Foot Subsonic 

Tunnel. Acceptable signal acquisitions from 1.0-micron PSL particles yielded high quality 

measurements with comparable flow field profiles that match the previous investigation 

with 1.7-micron PSL particles. The limitations of data transfer rate and acceptance of 

spurious noise spikes found in the first investigation were totally eliminated as issues. 

Plots to monitor statistical stationarity of the flow and scan profiles of the measurement 

results provide the user with additional information to better guide the flow investigation 

in real time. 

VII.8
Tying Up the Loose Ends

The laser velocimeter was moved back to the laboratory to experimentally determine 

several system characteristics. All measurement volume characteristics were previously 

determined using diffraction limited theory. Since the optical system is not diffraction 

limited, measurements of the actual diameter and length of the measurement volume were 

needed as a function of focal distance. Additionally an investigation of surface scatter was 

undertaken to find the surface preparation that would allow the closest approach of the 

measurement volume to the surface while yielding acceptable measurement signal-to-noise 

ratios. Finally, the signal/data processing software was linked back to the data acquisition 

software to transfer the results of the statistical stationarity test to the acquisition 

program. The acquisition program then compared the test result with the user supplied 

threshold, and if greater than the threshold, alert the user that stationarity had not been 

reached and that additional data should be acquired at that location and test condition. 

The signal/data processing program was also modified to combine the original and any 

repeat data ensembles to yield statistics for all data acquired at a given location and test 

condition.

Zoom lens calibrations

The investigation of the optical characteristics included the calibration of focal distance 

and cross-beam angle as a function of negative lens traverse position, and the 

determination of signal strength and signal-to-noise ratio from 1.0-micron PSL particles 

throughout the focal distance range. The manufacturer's specifications for the zoom lens 

are:

Transmission Mode

Laser Beam Input

Diameter, each beam 2.0 mm

Separation 50 mm

Beam Output

Diameter, each beam 0.44 to 0.50 inch

Separation 10.0 to 11.4 inches

Scan Distance 118 to 217 inches

Scan Element Movement 5.2 inches

Receiver Mode

Input Aperture Diameter 12 inches

Collimated Output Diameter 2.05 inches

General Parameters

Antireflection Coatings Magnesium Fluoride

Wavelengths 514.5 and 488.0 nm

VII.9
In this investigation the limits set by the manufacturer would be extended to determine 

the practical limits of focal distance based on signal strength and signal-to-noise ratio. To 

begin the negative lens was moved away from the focusing lens until the center of the 

beams reached the clear aperture of 12-inches. At this setting the focal distance was 

108 inches, but the available laser power was halved. Even with the reduced laser energy, 

the short focal distance allowed sufficient scattered light to be collected to obtain usable 

velocity measurements. The traversing mechanism was zeroed at this negative lens 

location. The lens was then moved to obtain calibration points at 108-, 126-, 180-, and 

300-inch focal distances, Figure VII.25. Although the zoom lens calibration of the original 

system was lost to history, the focal distance calibration was exponential and the crossbeam angle calibration was linear. The four-point calibration, Figures VII.25.a-d, have 

these same characteristics. 

At each of the four calibration locations, 1.0-micron PSL particles were sent through the 

measurement volume by a small particle generator to determine the signal amplitude and 

whether the signal-to-noise ratio was sufficient to obtain usable measurements. The 

captured signals that were accepted as viable measurements were interrogated to 

determine the peak of the high-pass filtered signal burst. The resulting histograms for the 

U-component (wavelength = 0.488 microns) are presented in Figure VII.25.e, and the 

histograms for the V-component (wavelength = 0.5145 microns) are presented in 

Figure VII.25.f. The lower amplitudes of the U-component signals were related to the 

lower efficiency of the fiber optics to transmit the blue light versus the green light in the 

V-component. In order to increase the probability of obtaining coincident measurements 

of the two components, the U-component was selected as the triggering source. The logic 

was if the lower amplitude signal was acceptable, the higher amplitude signal should also 

be acceptable. Additionally, any signal that failed to pass the signal-to-noise test in the 

signal/data processing software, that signal was most likely a U-component signal. The 

histograms show that the most efficient focal distance was 126 inches, and that signals 

obtained at 300 inches were within a factor of two of those obtained at 108 inches.

Although the four point calibration resulted in excellent curve fit results, a more detailed 

calibration was conducted on April 21, 2011 with a repeat conducted on April 28. The 

results are presented in Figures VII.26.a-d and found to be repeatable and within the 

uncertainty of the curve fits of the four point calibration. The calibrations were inverted, 

Figures VII.26.e and VII.26.f, to provide the user with negative lens position as a function 

of focal length so that the data acquisition program could automatically zoom the lens 

based on the desired focal distance.

Measurement volume characteristics

With the calibrations completed to allow the user to select a focal distance and command 

the zoom lens to place the measurement volume at that position, the next parameters to be 

determined were the diameter and length of the measurement volume as a function of focal 

distance. The diameter of the measurement volume was determined by first measuring 

the velocity of particles passing through the volume using the laser velocimeter. Then the 

VII.10
peak amplitude of each unfiltered signal was determined along with the temporal positions 

where the signal amplitude is 13.5-percent of the peak. The time difference between these 

two points equate to the time it took the particle to pass through the measurement volume 

based on the 1/e2 intensity points which are classically used to define the diameter. The 

diameter is then found by multiplying the measured velocity of a given particle and its 

passage time through the measurement volume. The results of this test are shown in 

Figure VII.27.a. The fact that the measurements do not track the theoretical predictions 

may be due to the use of fixed triggering of the PSL generated signal bursts which 

electronically reduce the measurement volume.

The length of the measurement volume was obtained by attaching a 127 micron 

(0.005-inch) diameter wire to a spinning wheel and aligning it so that the unattached end 

of the wire passed through the measurement volume. With the laser power greatly 

reduced, the wheel was translated along the optical axis until the peak signal was found. 

After noting the location, the wheel was first translated toward the zoom lens until the 

signal level was 80-percent of the peak, and the location noted. The wheel was then 

translated away from the zoom lens, passing through the peak signal to 80-percent of the 

peak at the far side. The difference between the two 80-percent locations represents the 

measurement volume length when the triggering oscilloscope is set to 80-percent of the 

peak of the signal bursts generated by the passage of PSL through the volume. The results 

of this test are compared to the diffraction limit theoretical predictions in Figure VII.27.b. 

As expected, the measurement volume length is greater than the predicted values, but not 

significantly, especially since the major increase in length is beyond lens specifications: 

324-inch focal distance versus the specification limit of 217-inches. This investigation was 

repeated with amplitudes from the 50-percent locations. These results are presented in 

Figure VII.27.c. The ability to electronically control the length of the measurement 

volume has the potential to increase spatial resolution in areas of high velocity gradients, 

yet increase data rate in quiescent flows by lowering the triggering threshold to increase 

the length of the measurement volume.

Flare from surfaces

A classic limitation of laser velocimetry is the inability to obtain measurements near 

surfaces because of flare from the impact and/or reflection of the laser light on/from the 

surface. This is especially true with coaxial backscatter configurations where the surface is 

orthogonal to the optical centerline because the flare occurs within the depth-of-field of the 

lens. For this configuration the only possible solution is finding a surface preparation that 

minimizes the flare generated by the impact of the laser beams. It is noted that the longer 

the focal distance, the greater the problem as the cross-beam angle decreases with focal 

distance bringing the impacts closer to the optical centerline, thus increasing the effective 

depth-of-field.

A laboratory investigation was conducted to determine the closest approach of a surface to 

the measurement volume for the following surface preparations:

VII.11
1) Flat black paint – classic standard used in previous laser velocimetry applications;

2) Untreated aluminum plate – Worse case sample;

3) Aeroglaze – a smooth surface, flat black type of surface preparation;

4) ChemGlaze – a glossy surface without the structure found in gloss paint; 

5) Semi-gloss black paint with Rhodamine B added – Worked well for Doppler global 

velocimetry applications – NOTE: All camera views in DGV were at least 30degrees 

from the light sheet optical axis; and,

6) Nanotube – a three-dimensional surface preparation composed of carbon 

nanotubes.

The test sequence began by setting the lens focal distance (120-, 180-, 228-, or 276-inches) 

and placing the target sample orthogonal to the optical axis 36-inches beyond the center of 

the measurement volume. Two standard, 4096 sample data acquisitions were obtained 

from 1.0-micron PSL particles emitted from the Royco particle generator placed at the 

center of the measurement volume and approximately 0.5-inches orthogonal to the optical 

axis so as to eliminate flare from the generator, yet close enough to obtain a usable flow 

velocity. The sample was then moved to a point 12-inches from the measurement volume 

and two data acquisitions were obtained. The sample was moved to a distance of 9-inches, 

then 6-inches with respective data ensembles acquired. Following the data acquisition at 

the 6-inch separation, the scan rig was used to move the measurement volume and particle 

generator toward the target sample until the sample was centered in the particle flow and 

measurement volume. The scan rig origin was reset to zero at this point. The rig was then 

scanned 3-inches away from the surface to obtain the scattering characteristics at that 

spatial distance. This method was used in order to obtain greater spatial accuracy at the 

smaller spatial distances than could be found using the tape measure employed at the 

greater spatial distances. The scan rig was used to move the measurement volume and 

Royco closer to the fixed surface location in a sequence of spatial distances until the signal 

bursts from the particle passage were buried in noise to the point where oscilloscope 

triggering was not possible. At longer focal distances, some surfaces produced sufficient 

noise that even the 6-inch station could not be reached.

The signal-to-noise ratio for this investigation was determined by dividing the peak 

spectral power by the average level throughout the power spectral density. The signal-tonoise ratio was computed for each captured signal burst, whether or not it was an accepted 

measurement. The mean and standard deviation of the signal-to-noise ratios were then 

determined and the results plotted for all surfaces at the four focal distances, 

Figure VII.28. The signal-to-noise ratio used to determine acceptable signal bursts was 5.0 

(7 dB). As shown in the figures, at the closer approaches a significant number of signal 

bursts were below the accepted threshold, and thus would be rejected from the velocity 

measurement statistics. Also it can be seen in the figures that the V-component had a far 

greater signal-to-noise ratio than the U-component, primarily due to its greater laser 

power. Thus, for coincident measurements, the U-component was the controller regarding 

size of the data ensemble and measurement quality.

VII.12
In general the signal-to-noise ratios obtained at the 36-inch spatial distance remained 

constant until the spatial distance decreased to the point where surface flare began to be 

collected by the optical system, thus increasing the noise level. Once this break point was 

reached, the decrease in signal-to-noise ratio followed a linear slope as plotted in semi-log. 

It is noted that the differences in signal-to-noise ratios at the 36-inch spatial distance were 

not sample surface dependent, but set primarily by the laser power for that particular test 

case. Although set nominally at 0.5 W (1.0 W at 276-inch focal distance) all-line output for 

each test, differences were found. As expected the closest approaches were obtained at the 

120-inch focal distance with the minimal approach distance increasing with increased focal 

distance. Also, as expected, the average signal-to-noise ratios also decreased with increased 

focal distance because the collecting solid angle decreased while the laser beam impacts 

occurred closer to the optical axis, thus resulting in decreasing signal strength while 

increasing the flare contribution to the noise level. Although the nanotube sample 

provided the closest approach at the 120- and 276-inch focal distances, the surface with the 

best overall characteristics was the Aeroglaze. It is also noted that the Rhodamine B doped 

semi-gloss black paint showed little overall improvement over plane semi-gloss black paint, 

Figure VII.28.a, even though it provided an improvement in DGV applications. This is 

most likely caused by the saturation of the absorption characteristics in the Rhodamine B 

because of the high power density at the laser beam impact locations versus the lower 

power densities found in laser light sheets.

Comparisons of signal-to-noise characteristics as a function of focal distance for each 

sample surface are presented in Figure VII.29. Again, the signal-to-noise levels at the 

36-inch separation distance are dependent on laser power and focal distance, and at the 

longer focal distances, contributions from surface flare. While each sample exhibits the 

onset of the flare effect at the 120-inch station, all of the samples, except the Aeroglaze, 

have no break point at the longer focal distances indicating that flare influences the 

measurements even at the 36-inch separation distance. During the course of testing a 

portion of the nanotube sample was damaged which may have affected its efficiency. Thus 

a comparison of the characteristics from the damaged section with the original was 

performed at the 276-inch focal distance, Figure VII.29.h. Surprisingly the damaged 

surface performed better than the original in having a clear break point and a closer 

approach distance.

In order to determine the optimal signal-to-noise threshold, the data was reprocessed with 

thresholds of 2.5 (5 dB) and 10.0 (10 dB) and the results presented in Figures VII.30-39. 

As an example, consider the characteristics found from the flat black painted sample, 

Figure VII.30.a. At the 120-inch focal distance, the number of acceptable signal bursts 

obtained using the 2.5 and 5.0 signal-to-noise levels are similar while there is a significant 

reduction in acceptable signal bursts at the 10.0 level as expected based on the number of 

signal bursts with signal-to-noise ratios below the threshold. However, the plots of mean 

velocity and standard deviation do not indicate any significant differences among the three 

thresholds. The mean velocity and standard deviation results were curve fit using iterative 

procedures to minimize error to fit a first order exponential decay function. As shown, 

there were significant changes in velocity and standard deviation that correlates with the 

VII.13
loss of signal-to-noise ratio, Figure VII.29.a. As the signal-to-noise ratio decreases with the 

inclusion of noise from surface flare, the probability density function widens, 

Figure VII.30.a.(2). The mean velocity is also affected by the loss of the lower signal-tonoise ratio bursts that are obtained from particles passing through the edge of the 

measurement volume which, in this case, are lower velocity since the measurement volume 

encompasses the entire diameter of the jet flow especially at the longer focal distances. 

As the focal distance increases the differences in the number of acceptable signal bursts 

becomes significant, while measurement accuracies decrease. The decrease in 

measurement accuracy is found first in the signal-to-noise ratio threshold of 2.5 as shown 

in the plots of mean velocity and standard deviation along with the histograms. Data 

processed using the threshold of 5.0 remain consistent until the focal distance reaches 

276-inches. At that focal distance the threshold of 10.0 remains consistent except that the 

number of acceptable signal bursts becomes so low that statistical uncertainty becomes an 

issue. Thus it is recommended that a threshold of 5.0 be used during real time data 

processing because of its relative insensitivity to noise while providing higher numbers of 

acceptable signal bursts to minimize statistical uncertainties. The threshold of 5.0 was 

used during the processing of all data acquired in both BART entries, the results of which 

are presented in this document.

The above characteristics were found with all of the surface samples:

Figure VII.31 – Unpainted aluminum sample;

Figure VII.32 – Semi-gloss black paint (no Rhodamine);

Figure VII.33 – Aeroglaze;

Figure VII.34 – Chem Glaze;

Figure VII.35 – Semi-gloss black paint with Rhodamine B added; 

Figures VII.36-38 – illustrate the effect of aging of the Rhodamine B; and,

Figure VII.39 – Nanotube.

Since testing in facilities would normally scan the measurement volume in a plane normal 

to the optical axis at a fixed focal distance, any flare from the model surface could not be 

predicted because of the lack of a clear break point, as found in this investigation, leading 

to the potential of unknown measurement uncertainties. While monitoring the 

oscilloscope traces of the signal bursts would provide an indication of the increase in noise 

caused by surface flare, this is not a practical solution in the hectic world of wind tunnel 

testing. Thus it is recommended that post processing be conducted using the 2.5 and 10.0 

signal-to-noise thresholds along with the real time processing using the 5.0 threshold to 

ascertain the onset of measurement uncertainty due to surface flare. It is noted that the 

loss of signal-to-noise ratio related to focal distance or lower laser power has a far lower 

effect on measurement accuracy than the increase in noise caused by surface flare. It is 

further recommended that Aeroglaze be used as a surface coating on the areas of the model 

that would be impacted by the laser beams during testing. Also, if found to be practical, 

off-axis collection of the scattered light will greatly reduce the amount of collected flare 

light, thus allowing a closer approach to the surface without compromising measurement 

accuracy, (Meyers and Hepner (1984)).

VII.14
Figure VII.1.a.- Vertical scans at several downstream locations in the jet exiting the 2-inch jet: Streamwise 

velocity.

VII.15

X = 0.125 inches

X = 2.0 inches

X = 4.0 inches

X = 6.0 inches

X = 8.25 inches

X = 10.25 inches

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

600

650

700

750

800

850

900

950

1000

Number of measurements

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

0

5

10

15

20

25

30

35

40

45

50

55

U-component meanvelocity, m/s

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

0

1

2

3

4

5

6

7

8

9

U-component velocity standard deviation, m/s

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

U-compoent velocity skew

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2

0

2

4

6

8

10

12

U-component velocity excess

Height above pipe center, inch
Figure VII.1.b.- Vertical scans at several downstream locations in the jet exiting the 2-inch jet: Vertical 

velocity.

VII.16

X = 0.125 inches

X = 2.0 inches

X = 4.0 inches

X = 6.0 inches

X = 8.25 inches

X = 10.25 inches

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

600

650

700

750

800

850

900

950

1000

Number of measurements

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

V-component mean velocity, m/s

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

0

1

2

3

4

5

6

7

8

9

V-component velocity standarddeviation, m/s

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

V-compoent velocity skew

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2

0

2

4

6

8

10

12

V-component velocity excess

Height above pipe center, inch
Figure VII.1.c.- Vertical scans at several downstream locations in the jet exiting the 2-inch jet: Velocity 

magnitude.

VII.17

X = 0.125 inches

X = 2.0 inches

X = 4.0 inches

X = 6.0 inches

X = 8.25 inches

X = 10.25 inches

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

600

650

700

750

800

850

900

950

1000

Number of measurements

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

0

5

10

15

20

25

30

35

40

45

50

55

Mean velocity magnitude, m/s

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

0

1

2

3

4

5

6

7

8

9

Velocity magnitudestandard deviation, m/s

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Velocity magnitude skew

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2

0

2

4

6

8

10

12

Velocity magnitude excess

Height above pipe center, inch
Figure VII.1.d.- Vertical scans at several downstream locations in the jet exiting the 2-inch jet: Flow angle.

VII.18

X = 0.125 inches

X = 2.0 inches

X = 4.0 inches

X = 6.0 inches

X = 8.25 inches

X = 10.25 inches

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

600

650

700

750

800

850

900

950

1000

Number of measurements

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-10

-8

-6

-4

-2

0

2

4

6

8

10

Height above pipe center, inch

Alpha mean, degree

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

0

10

20

30

40

50

60

70

80

Height above pipe center, inch

Alpha standard deviation, degree

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Height above pipe center, inch

Alpha skew

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2

0

2

4

6

8

10

12

Height above pipe center, inch

Alpha excess
Figure VII.2.a.- Vertical scan repeat test at 10.25-inches downstream: Streamwise velocity.

VII.19

X = 10.25 inches

X = 10.25 inches

 (repeat)

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

600

650

700

750

800

850

900

950

1000

Number of measurements

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

0

5

10

15

20

25

30

35

40

45

50

55

U-component meanvelocity, m/s

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

0

1

2

3

4

5

6

7

8

9

U-component velocity standard deviation, m/s

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

U-compoent velocity skew

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2

0

2

4

6

8

10

12

U-component velocity excess

Height above pipe center, inch
Figure VII.2.b.- Vertical scan repeat test at 10.25-inches downstream: Vertical velocity.

VII.20

X = 10.25 inches

X = 10.25 inches

 (repeat)

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

600

650

700

750

800

850

900

950

1000

Number of measurements

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

V-component mean velocity, m/s

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

0

1

2

3

4

5

6

7

8

9

V-component velocity standarddeviation, m/s

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

V-compoent velocity skew

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2

0

2

4

6

8

10

12

V-component velocity excess

Height above pipe center, inch
Figure VII.2.c.- Vertical scan repeat test at 10.25-inches downstream: Velocity magnitude.

VII.21

X = 10.25 inches

X = 10.25 inches

 (repeat)

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

600

650

700

750

800

850

900

950

1000

Number of measurements

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

0

5

10

15

20

25

30

35

40

45

50

55

Velocity magnitude, m/s

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

0

1

2

3

4

5

6

7

8

9

Velocity magnitudestandard deviation, m/s

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Velocity magnitude skew

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2

0

2

4

6

8

10

12

Velocity magnitude excess

Height above pipe center, inch
Figure VII.2.d.- Vertical scan repeat test at 10.25-inches downstream: Flow angle.

VII.22

X = 10.25 inches

X = 10.25 inches

 (repeat)

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

600

650

700

750

800

850

900

950

1000

Number of measurements

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-10

-8

-6

-4

-2

0

2

4

6

8

10

Alphamean, degree

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

0

10

20

30

40

50

60

70

80

Alphastandard deviation, degree

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Alpha skew

Height above pipe center, inch

-2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-2

0

2

4

6

8

10

12

Alpha excess

Height above pipe center, inch
Figure VII.3.a.- Vertical scan azimuth test (uniform random number based) at several downstream 

locations: Streamwise velocity.

VII.23

X = 0.125 inches

X = 2.0 inches

X = 4.0 inches

X = 6.0 inches

X = 8.25 inches

X = 10.25 inches

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

10

20

30

40

50

60

70

80

90

100

Numberof signal bursts

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

5

10

15

20

25

30

35

40

45

50

55

U-component velocity mean, m/s

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

1

2

3

4

5

6

7

8

9

U-component velocity standard deviation, m/s

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

U-component velocity skew

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

-2

0

2

4

6

8

10

12

U-component velocity excess

Azimuth, degree
Figure VII.3.b.- Vertical scan azimuth test (uniform random number based) at several downstream 

locations: Vertical velocity.

VII.24

X = 0.125 inches

X = 2.0 inches

X = 4.0 inches

X = 6.0 inches

X = 8.25 inches

X = 10.25 inches

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

10

20

30

40

50

60

70

80

90

100

Numberof signal bursts

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

V-component velocity mean, m/s

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

1

2

3

4

5

6

7

8

9

V-component velocity standard deviation, m/s

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

V-component velocity skew

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

-2

0

2

4

6

8

10

12

V-component velocity excess

Azimuth, degree
Figure VII.3.c.- Vertical scan azimuth test (uniform random number based) at several downstream 

locations: Velocity magnitude.

VII.25

X = 0.125 inches

X = 2.0 inches

X = 4.0 inches

X = 6.0 inches

X = 8.25 inches

X = 10.25 inches

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

10

20

30

40

50

60

70

80

90

100

Numberof signal bursts

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

5

10

15

20

25

30

35

40

45

50

55

Mean velocity magnitude, m/s

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

1

2

3

4

5

6

7

8

9

Velocity magnitude standard deviation, m/s

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Velocity magnitudeskew

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

-2

0

2

4

6

8

10

12

Velocity magnitudeexcess

Azimuth, degree
Figure VII.3.d.- Vertical scan azimuth test (uniform random number based) at several downstream 

locations: Flow angle.

VII.26

X = 0.125 inches

X = 2.0 inches

X = 4.0 inches

X = 6.0 inches

X = 8.25 inches

X = 10.25 inches

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

10

20

30

40

50

60

70

80

90

100

Numberof signal bursts

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

-10

-8

-6

-4

-2

0

2

4

6

8

10

Meanalpha, degree

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

0

10

20

30

40

50

60

70

80

Alphastandard deviation, degree

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Alphaskew

Azimuth, degree

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

-2

0

2

4

6

8

10

12

Alpha excess

Azimuth, degree
Figure VII.4.a.- Vertical scan 0.262 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.27

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble 

 14x22 LV: X = 0.262 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 0.262 x/H
Figure VII.4.b.- Vertical scan 0.535 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.28

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.535 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.535 x/H

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble

 14x22 LV: X = 0.535 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 0.535 x/H
Figure VII.4.c.- Vertical scan 0.787 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.29

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble

 14x22 LV: X = 0.787 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 0.787 x/H
Figure VII.4.d.- Vertical scan 1.050 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.30

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble

 14x22 LV: X = 1.050 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 1.050 x/H
Figure VII.4.e.- Vertical scan 1.313 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.31

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble

 14x22 LV: X = 1.313 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 1.313 x/H
Figure VII.4.f.- Vertical scan 1.575 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.32

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H

Vertical distance, step height

V-component velocity mean, m/s

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

 14x22 LV: X = 1.575 x/H

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble

 14x22 LV: X = 1.575 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 1.575 x/H
Figure VII.4.g.- Vertical scan 1.837 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.33

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble

 14x22 LV: X = 1.837 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 1.837 x/H
Figure VII.4.h.- Vertical scan 2.1 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.34

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

 14x22 LV: X = 2.100 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 2.100 x/H

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

V-component velocity mean, m/s

 14x22 LV: X = 2.100 x/H

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signal in the ensemble

 14x22 LV: X = 2.100 x/H
Figure VII.4.i.- Vertical scan 2.362 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.35

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.362 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.362 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.632 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.632 x/H

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble

 14x22 LV: X = 2.362 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 2.362 x/H
Figure VII.4.j.- Vertical scan 2.625 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.36

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.625 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.625 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.625 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.625 x/H

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble

 14x22 LV: X = 2.625 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 2.625 x/H
Figure VII.4.k.- Vertical scan 2.887 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.37

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.887 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.887 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.887 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.887 x/H

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble

 14x22 LV: X = 2.887 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 2.887 x/H
Figure VII.4.l.- Vertical scan 3.149 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.38

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.149 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.149 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.149 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.149 x/H

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble

 14x22 LV: X = 3.149 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 3.149 x/H
Figure VII.4.m.- Vertical scan 3.412 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.39

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.412 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.412 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ /fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.412 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.412 x/H

V ertica l dis tance, s tep height

V-component standard deviation, σ /fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

V er tic al distanc e, s tep height

Number of valid signals in the ensemble

 14x22 LV: X = 3.412 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

V er tic al distanc e, s tep height

Convergence - average standard deviation, m/s

 14x22 LV: X = 3.412 x/H
Figure VII.4.n.- Vertical scan 3.675 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.40

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.675 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.675 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.675 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.675 x/H

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble

 14x22 LV: X = 3.675 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 3.675 x/H
Figure VII.4.o.- Vertical scan 3.937 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.41

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.937 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.937 x/H

 BART LV: X = 0.530 x/H

Vertical distance, step height

U-component standard deviation, σ U/fs, percent

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.937 x/H

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.937 x/H

Vertical distance, step height

V-component standard deviation, σ V/fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Number of valid signals in the ensemble

 14x22 LV: X = 3.937 x/H

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

Vertical distance, step height

Convergence - average standard deviation, m/s

 14x22 LV: X = 3.937 x/H
Figure VII.5.a.- Horizontal scan 0.575 z/H above a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.42

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.575 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.575 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = 0.575 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.575 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = 0.575 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = 0.575 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.b.- Horizontal scan 0.313 z/H above a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.43

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.313 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.313 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = 0.313 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.313 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = 0.313 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = 0.313 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.c.- Horizontal scan 0.181 z/H above a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.44

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.181 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.181 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = 0.181 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.181 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = 0.181 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = 0.181 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.d.- Horizontal scan 0.050 z/H above a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.45

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.050 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.050 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = 0.050 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.050 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = 0.050 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = 0.050 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.e.- Horizontal scan 0.090 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.46

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.090 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.090 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.090 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.090 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.090 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.090 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.f.- Horizontal scan 0.220 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.47

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.220 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.220 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.220 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.220 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.220 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.220 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.g.- Horizontal scan 0.344 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.48

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.344 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.344 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.344 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.344 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.344 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.344 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.h.- Horizontal scan 0.475 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.49

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.475 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.475 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.475 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.475 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.475 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.475 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.i.- Horizontal scan 0.606 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.50

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.606 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.606 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.606 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.606 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.606 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.606 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.j.- Horizontal scan 0.703 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.51

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.703 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.703 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.703 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.703 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.703 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.703 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.k.- Horizontal scan 0.755 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.52

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.755 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.755 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.755 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.755 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.755 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.755 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.l.- Horizontal scan 0.806 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.53

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.806 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.806 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.806 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.806 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.806 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.806 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.m.- Horizontal scan 0.858 z/H below a 1.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.54

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.858 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.858 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.858 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.858 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.858 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.858 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.5.n.- Horizontal scan 0.911 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity components, number of accepted signal bursts, and statistical stationarity convergence standard 

deviation, fs = 45.0 m/s.

VII.55

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.911 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.911 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.911 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.089 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.911 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.911 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.6.a.- Vertical scan 0.262 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.56

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.b.- Vertical scan 0.525 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.57

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.c.- Vertical scan 0.787 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.58

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.d.- Vertical scan 1.050 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.59

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H

Vertical distance, st ep height

Mean velocity magnitude, m/s

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.e.- Vertical scan 1.313 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.60

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.f.- Vertical scan 1.575 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.61

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.g.- Vertical scan 1.837 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.62

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H

Vertical distan ce, step h eig ht

Mean flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H

Vertical distan ce, step h eig ht

Flow angle standard deviation, degrees
Figure VII.6.h.- Vertical scan 2.1 x/H downstream of a 1.5-inch backward-facing step: velocity magnitude 

and flow angle, fs = 45.0 m/s.

VII.63

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.i.- Vertical scan 2.362 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.64

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.362 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.362 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.362 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.362 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.j.- Vertical scan 2.625 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.65

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.625 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.625 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.625 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.625 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.k.- Vertical scan 2.887 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.66

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.887 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.887 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.887 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.887 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.l.- Vertical scan 3.149 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.67

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.149 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.149 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.149 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.149 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.m.- Vertical scan 3.412 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.68

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.412 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.412 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.412 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.412 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.n.- Vertical scan 3.675 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.69

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.675 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.675 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.675 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.6.o.- Vertical scan 3.938 x/H downstream of a 1.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.70

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.938 x/H

Vertical distance, st ep height

Mean velocity magnitude, Mag/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.938 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.938 x/H

Vertical distan ce, step h eig ht

Mean vertical flow angle, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.938 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.7.a.- Horizontal scan 0.575 z/H above a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.71

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.575 z/H

Mean velocity magnitude, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.575 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = 0.575 z/H

Mean flowangle, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = 0.575 z/H

Flowangle standard deviation, degrees

Distance downstream from step, x/H
Figure VII.7.b.- Horizontal scan 0.313 z/H above a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.72

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.313 z/H

Mean velocity magnitude, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.313 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = 0.313 z/H

Mean flowangle, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = 0.313 z/H

Flowangle standard deviation, degrees

Distance downstream from step, x/H
Figure VII.7.c.- Horizontal scan 0.181 z/H above a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.73

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.181 z/H

Mean velocity magnitude, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.181 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = 0.181 z/H

Mean flowangle, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = 0.181 z/H

Flowangle standard deviation, degrees

Distance downstream from step, x/H
Figure VII.7.d.- Horizontal scan 0.050 z/H above a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.74

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.050 z/H

Mean velocity magnitude, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.050 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = 0.050 z/H

Mean flowangle, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = 0.050 z/H

Flowangle standard deviation, degrees

Distance downstream from step, x/H
Figure VII.7.e.- Horizontal scan 0.090 z/H below a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.75

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.090 z/H

Mean velocity magnitude, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.090 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.090 z/H

Mean flowangle, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.090 z/H

Flowangle standard deviation, degrees

Distance downstream from step, x/H
Figure VII.7.f.- Horizontal scan 0.220 z/H below a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.76

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.220 z/H

Mea n velocity magn itu de , M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.220 z/H

V elo city magn itude standar d devia tio n, σ M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.220 z/H

Me an flow angle, deg ree s

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.220 z/H

Flo w angle stan da rd de viation, deg rees

Distance downstream from step, x/H
Figure VII.7.g.- Horizontal scan 0.344 z/H below a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.77

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.344 z/H

Mean velocity magnitude, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.344 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.344 z/H

Mean flowangle, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.344 z/H

Flowangle standard deviation, degrees

Distance downstream from step, x/H
Figure VII.7.h.- Horizontal scan 0.475 z/H below a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.78

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.475 z/H

Mean velocity magnitude, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.475 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.475 z/H

Mean flowangle, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.475 z/H

Flowangle standard deviation, degrees

Distance downstream from step, x/H
Figure VII.7.i.- Horizontal scan 0.606 z/H below a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.79

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.606 z/H

Mean velocity magnitude, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.606 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.606 z/H

Mean flowangle, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.606 z/H

Flowangle standard deviation, degrees

Distance downstream from step, x/H
Figure VII.7.j.- Horizontal scan 0.703 z/H below a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.80

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.703 z/H

Mean velocity magnitude, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.703 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.703 z/H

Mean flowangle, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.703 z/H

Flowangle standard deviation, degrees

Distance downstream from step, x/H
Figure VII.7.k.- Horizontal scan 0.755 z/H below a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.81

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.755 z/H

Mean velocity magnitude, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.755 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.755 z/H

Mean flowangle, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.755 z/H

Flowangle standard deviation, degrees

Distance downstream from step, x/H
Figure VII.7.l.- Horizontal scan 0.806 z/H below a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.82

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.806 z/H

Mean velocity magnitude, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.806 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.806 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.806 z/H

Mean vertical flowangle, degrees

Distance downstream from step, x/H
Figure VII.7.m.- Horizontal scan 0.858 z/H below a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.83

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.858 z/H

Mean velocity magnitude, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.858 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.858 z/H

Mean flowangle, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.858 z/H

Flowangle standard deviation, degrees

Distance downstream from step, x/H
Figure VII.7.n.- Horizontal scan 0.911 z/H below a 1.5-inch backward-facing step: velocity magnitude and 

flow angle, fs = 45.0 m/s.

VII.84

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.911 z/H

Mean velocity magnitude, Mag/fs

Distance downstream of step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.911 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream of step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.911 z/H

Mean vertical flowangle, degrees

Distance downstream of step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.911 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream of step, x/H
Figure VII.8.a.- Vertical scan 0.262 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.85

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.262 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.b.- Vertical scan 0.525 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.86

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.c.- Vertical scan 0.787 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.87

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.d.- Vertical scan 1.050 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.88

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.e.- Vertical scan 1.313 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.89

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.f.- Vertical scan 1.575 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.90

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H

Ver tical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H

Ver tical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.g.- Vertical scan 1.837 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.91

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.h.- Vertical scan 2.1 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.92

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.i.- Vertical scan 2.362 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.93

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.362 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.362 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.362 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.362 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.j.- Vertical scan 2.625 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.94

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.625 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.625 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.625 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.625 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.k.- Vertical scan 2.887 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.95

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.887 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.887 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.887 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.887 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.l.- Vertical scan 3.149 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.96

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.149 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.149 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.149 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.149 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.m.- Vertical scan 3.412 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.97

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.412 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.412 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.412 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.412 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.n.- Vertical scan 3.675 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.98

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.675 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.675 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.675 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.675 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.8.o.- Vertical scan 3.938 x/H downstream of a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.99

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.938 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.938 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.938 x/H

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 3.938 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.9.a.- Horizontal scan 0.575 z/H above a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.100

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = 0.575 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.575 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = 0.575 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = 0.575 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.b.- Horizontal scan 0.313 z/H above a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.101

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = 0.313 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.313 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = 0.313 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = 0.313 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.c.- Horizontal scan 0.181 z/H above a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.102

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = 0.181 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.181 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = 0.181 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = 0.181 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.d.- Horizontal scan 0.050 z/H above a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.103

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = 0.050 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.050 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = 0.050 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = 0.050 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.e.- Horizontal scan 0.090 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.104

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.090 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.090 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.090 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.090 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.f.- Horizontal scan 0.220 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.105

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.220 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.220 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.220 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.220 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.g.- Horizontal scan 0.344 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.106

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.344 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.344 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.344 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.344 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.h.- Horizontal scan 0.475 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.107

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.475 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.475 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.475 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.475 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.i.- Horizontal scan 0.606 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.108

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.606 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.606 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.606 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.606 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.j.- Horizontal scan 0.703 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.109

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.703 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.703 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.703 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.703 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.k.- Horizontal scan 0.755 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.110

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.755 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.755 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.755 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.755 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.l.- Horizontal scan 0.806 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.111

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.806 z/H

U-component skew

Distance downstream of step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.806 z/H

V-component skew

Distance downstream of step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.806 z/H

Flow angleskew

Distance downstream of step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.806 z/H

Distance downstream of step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.m.- Horizontal scan 0.858 z/H below a 1.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.112

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.858 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.858 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.858 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.858 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.9.n.- Horizontal scan 0.911 z/H below a 1.5-inch backward-facing step: streamwise and vertical 

velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.113

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.911 z/H

U-component skew

Distance downstream of step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.911 z/H

V-component skew

Distance downstream of step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.911 z/H

Vertical flowangle skew

Distance downstream of step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.911 z/H

Distance downstream of step, x/H

Reynolds stress, m /s 2 2
Figure VII.10.a.- Vertical scan 0.525 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.4.b): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.114

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical distance, step height

U-component standard deviation, σ /fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical distance, step height

V-component standard deviation, σ /fs

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical distance, step height

V-component velocity mean, V/fs
Figure VII.10.b.- Vertical scan 0.656 x/H downstream of a 3.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.115

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical distance, step height

U-component standard deviation, σ /fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical distance, step height

V-component standard deviation, σ /fs

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical distance, step height

V-component velocity mean, V/fs
Figure VII.10.c.- Vertical scan 0.787 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.4.c): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.116

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distance, step height

U-component standard deviation, σ /fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distance, step height

V-component standard deviation, σ /fs

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distance, step height

V-component velocity mean, V/fs
Figure VII.10.d.- Vertical scan 0.919 x/H downstream of a 3.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.117

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Vertical distance, step height

U-component standard deviation, σ /fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Vertical distance, step height

V-component standard deviation, σ /fs

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Vertical distance, step height

V-component velocity mean, V/fs
Figure VII.10.e.- Vertical scan 1.050 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.4.d): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.118

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distance, step height

U-component standard deviation, σ /fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distance, step height

V-component standard deviation, σ /fs

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distance, step height

V-component velocity mean, V/fs
Figure VII.10.f.- Vertical scan 1.181 x/H downstream of a 3.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.119

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distance, step height

U-component standard deviation, σ /fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distance, step height

V-component standard deviation, σ /fs

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distance, step height

V-component velocity mean, V/fs
Figure VII.10.g.- Vertical scan 1.312 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.4.e): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.120

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distance, step height

U-component standard deviation, σ /fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distance, step height

V-component standard deviation, σ /fs

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distance, step height

V-component velocity mean, V/fs
Figure VII.10.h.- Vertical scan 1.443 x/H downstream of a 3.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.121

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distance, step height

U-component standard deviation, σ /fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distance, step height

V-component standard deviation, σ /fs

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distance, step height

V-component velocity mean, V/fs
Figure VII.10.i.- Vertical scan 1.575 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.4.f): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.122

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distance, step height

U-component standard deviation, σ /fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distance, step height

V-component standard deviation, σ /fs

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distance, step height

V-component velocity mean, V/fs
Figure VII.10.j.- Vertical scan 1.706 x/H downstream of a 3.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.123

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distance, step height

U-component standard deviation, σ /fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distance, step height

V-component standard deviation, σ /fs

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distance, step height

V-component velocity mean, V/fs
Figure VII.10.k.- Vertical scan 1.969 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.4.g): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.124

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical distance, step height

U-component standard deviation, σ /fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical distance, step height

V-component standard deviation, σ /fs

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical distance, step height

V-component velocity mean, V/fs
Figure VII.10.l.- Vertical scan 2.1 x/H downstream of a 3.5-inch backward-facing step: streamwise and 

vertical velocity components, number of accepted signal bursts, and statistical stationarity convergence 

standard deviation, fs = 45.0 m/s.

VII.125

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical distance, step height

U-component standard deviation, σ /fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical distance, step height

V-component standard deviation, σ /fs

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical distance, step height

V-component velocity mean, V/fs
Figure VII.11.a. - Horizontal scan 0.312 z/H above a 3.5-inch backward-facing step (compares to 

Figure VII.5.b): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.126

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.312 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.312 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.312 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = 0.312 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = 0.312 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = 0.312 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.11.b. - Horizontal scan 0.181 z/H above a 3.5-inch backward-facing step (compares to 

Figure VII.5.c): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.127

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.181 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.181 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.181 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = 0.181 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = 0.181 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = 0.181 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.11.c. - Horizontal scan 0.050 z/H above a 3.5-inch backward-facing step (compares to 

Figure VII.5.d): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.128

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.050 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.050 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.050 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = 0.050 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = 0.050 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = 0.050 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.11.d. - Horizontal scan 0.081 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.5.e): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.129

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.081 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.081 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.081 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.081 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.081 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.081 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.11.e. - Horizontal scan 0.213 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.5.f): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.130

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.213 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.213 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4 5 6 7 8

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.213 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.213 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.213 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.213 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.11.f. - Horizontal scan 0.344 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.5.g): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.131

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.344 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.344 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.344 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.344 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.344 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.344 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.11.g. - Horizontal scan 0.475 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.5.h): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.132

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.475 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.475 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.475 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.475 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.475 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.475 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.11.h. - Horizontal scan 0.606 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.5.i): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.133

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.606 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.606 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.606 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.606 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.606 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.606 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.11.i. - Horizontal scan 0.701 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.5.j): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.134

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.701 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.701 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.701 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.701 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.701 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.701 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.11.j. - Horizontal scan 0.753 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.5.k): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.135

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.753 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.753 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.753 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.753 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.753 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.753 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.11.k. - Horizontal scan 0.806 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.5.l): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.136

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.806 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.806 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.806 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.806 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.806 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.806 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.11.l. - Horizontal scan 0.858 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.5.m): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.137

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.858 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.858 z/H

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.858 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.858 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.858 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.858 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.11.m. - Horizontal scan 0.911 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.5.n): streamwise and vertical velocity components, number of accepted signal bursts, and 

statistical stationarity convergence standard deviation, fs = 45.0 m/s.

VII.138

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.911 z/H

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.911 z/H

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.911 z/H

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.911 z/H

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.911 z/H

Convergence - average standard deviation, m/s

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.911 z/H

V-component velocity mean, V/fs

Distance downstream from step, x/H
Figure VII.12.a.- Vertical scan 0.525 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.6.b): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.139

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical dista nce, step heig ht

Velocity magnitude standard deviation, σ /fs
Figure VII.12.b.- Vertical scan 0.656 x/H downstream of a 3.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.140

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical dista nce, step heig ht

Velocity magnitude standard deviation, σ /fs
Figure VII.12.c.- Vertical scan 0.787 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.6.c): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.141

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.12.d.- Vertical scan 0.919 x/H downstream of a 3.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.142

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.12.e.- Vertical scan 1.050 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.6.d): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.143

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.12.f.- Vertical scan 1.181 x/H downstream of a 3.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.144

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.12.g.- Vertical scan 1.312 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.6.e): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.145

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.12.h.- Vertical scan 1.443 x/H downstream of a 3.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.146

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distan ce, step h eig ht

Flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distan ce, step h eig ht

Flow angle standard deviation, degrees
Figure VII.12.i.- Vertical scan 1.575 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.6.f): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.147

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.12.j.- Vertical scan 1.706 x/H downstream of a 3.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.148

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.12.k.- Vertical scan 1.837 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.6.g): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.149

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.837 x/H

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.837 x/H

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.837 x/H

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.837 x/H

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.12.l.- Vertical scan 1.969 x/H downstream of a 3.5-inch backward-facing step: velocity 

magnitude and flow angle, fs = 45.0 m/s.

VII.150

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical distance, step h eig ht

Velocity magnitude mean, m/s

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical distance, step h eig ht

Velocity magnitude standard deviation, m/s

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical dista nce , ste p height

Flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical dista nce , ste p height

Flow angle standard deviation, degrees
Figure VII.12.m.- Vertical scan 2.1 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.6.h): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.151

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical distance, step h eig ht

Velocity magnitude mean, m/s

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical distance, step h eig ht

Velocity magnitude standard deviation, m/s

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical dista nce , ste p height

Flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical dista nce , ste p height

Flow angle standard deviation, degrees
Figure VII.13.a.- Horizontal scan 0.312 z/H above a 3.5-inch backward-facing step (compares to 

Figure VII.7.b): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.152

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.312 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = 0.312 z/H

Vertical flow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.312 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = 0.312 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.13.b.- Horizontal scan 0.181 z/H above a 3.5-inch backward-facing step (compares to 

Figure VII.7.c): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.153

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.181 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = 0.181 z/H

Vertical flow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.181 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = 0.181 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.13.c.- Horizontal scan 0.050 z/H above a 3.5-inch backward-facing step (compares to 

Figure VII.7.d): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.154

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.050 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = 0.050 z/H

Vertical flow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.050 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = 0.050 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.13.d.- Horizontal scan 0.081 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.7.e): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.155

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.081 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.081 z/H

Vertical flow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.081 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.081 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.13.e.- Horizontal scan 2.13 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.7.f): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.156

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.213 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.213 z/H

Vertical flow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4 5 6 7 8

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.213 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.213 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.13.f.- Horizontal scan 0.344 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.7.g): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.157

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.344 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.344 z/H

Vertical flow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.344 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.344 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.13.g.- Horizontal scan 0.475 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.7.h): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.158

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.475 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.475 z/H

Vertical flow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.475 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.475 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.13.h.- Horizontal scan 0.606 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.7.i): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.159

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.606 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.606 z/H

Vertical flow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

1

2

3

4

5

6

7

8

9

10

11

12

 14x22 LV: Z = -0.606 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.606 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.13.i.- Horizontal scan 0.701 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.7.j): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.160

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.701 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.701 z/H

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

Velocity magnitude standard deviation, σ M/fs

 14x22 LV: Z = -0.701 z/H

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.701 z/H

Vertical flow angle standard deviation, degrees

Distance downstream from step, x/H
Figure VII.13.j.- Horizontal scan 0.753 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.7.k): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.161

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.753 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.753 z/H

Vertical flow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.753 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.753 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.13.k.- Horizontal scan 0.806 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.7.l): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.162

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.806 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.806 z/H

Vertical flow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.806 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.806 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.13.l.- Horizontal scan 0.858 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.7.m): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.163

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.858 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.858 z/H

Vertical flow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.858 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.858 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.13.m.- Horizontal scan 0.911 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.7.n): velocity magnitude and flow angle, fs = 45.0 m/s.

VII.164

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.911 z/H

Velocity magnitude mean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.911 z/H

Vertical flow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.911 z/H

Velocity magnitude standard deviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.911 z/H

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.14.a.- Vertical scan 0.525 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.8.b): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 

m/s.

VII.165

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.525 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.14.b.- Vertical scan 0.656 x/H downstream of a 3.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.166

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.656 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.14.c.- Vertical scan 0.787 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.8.c): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 

m/s.

VII.167

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.787 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.14.d.- Vertical scan 0.919 x/H downstream of a 3.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.168

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

H eig ht above step floor, in ch

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 0.919 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.14.e.- Vertical scan 1.050 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.8.d): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 

m/s.

VII.169

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.050 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.14.f.- Vertical scan 1.181 x/H downstream of a 3.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.170

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.181 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.14.g.- Vertical scan 1.312 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.8.e): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 

m/s.

VII.171

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.312 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.14.h.- Vertical scan 1.443 x/H downstream of a 3.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.172

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.443 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.14.i.- Vertical scan 1.575 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.8.f): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.173

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.575 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.14.j.- Vertical scan 1.706 x/H downstream of a 3.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.174

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.706 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.14.k.- Vertical scan 1.837 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.8.g): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 

m/s.

VII.175

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.837 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.837 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.837 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.837 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.14.l.- Vertical scan 1.969 x/H downstream of a 3.5-inch backward-facing step: streamwise and 

vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.176

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 1.969 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.14.m.- Vertical scan 2.1 x/H downstream of a 3.5-inch backward-facing step (compares to 

Figure VII.8.h): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 

m/s.

VII.177

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical distance, step heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical distance, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Vertical distance, step height

Flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: Z = 2.100 x/H

Ve rtica l distance, step he igh t

Reynolds stress, m/s2 2
Figure VII.15.a.- Horizontal scan 0.312 z/H above a 3.5-inch backward-facing step (compares to 

Figure VII.9.b): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, 

fs = 45.0 m/s.

VII.178

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = 0.312 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.312 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = 0.312 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = 0.312 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.15.b.- Horizontal scan 0.181 z/H above a 3.5-inch backward-facing step (compares to 

Figure VII.9.c): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, 

fs = 45.0 m/s.

VII.179

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = 0.181 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.181 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = 0.181 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = 0.181 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.15.c.- Horizontal scan 0.050 z/H above a 3.5-inch backward-facing step (compares to 

Figure VII.9.d): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, 

fs = 45.0 m/s.

VII.180

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = 0.050 z/H

U-component skew

Distance downstream of step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.050 z/H

V-component skew

Distance downstream of step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = 0.050 z/H

Flow angle skew

Distance downstream of step, x/H

Re yno lds stre ss, m /s 2 2

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = 0.050 z/H

Distance downstream of step, x/H
Figure VII.15.d.- Horizontal scan 0.081 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.9.e): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, 

fs = 45.0 m/s.

VII.181

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.081 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.081 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.081 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.081 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.15.e.- Horizontal scan 0.213 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.9.f): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.182

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.213 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.213 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.213 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.213 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.15.f.- Horizontal scan 0.344 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.9.g): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, 

fs = 45.0 m/s.

VII.183

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.344 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.344 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.344 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.344 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.15.g.- Horizontal scan 0.475 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.9.h): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, 

fs = 45.0 m/s.

VII.184

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.475 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.475 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.475 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.475 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.15.h.- Horizontal scan 0.606 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.9.i): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.185

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.606 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.606 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.606 z/H

 Z = 1.378 inches above tunnel floor

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.606 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.15.i.- Horizontal scan 0.701 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.9.j): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.186

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.701 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.701 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.701 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.701 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.15.j.- Horizontal scan 0.753 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.9.k): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, 

fs = 45.0 m/s.

VII.187

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.753 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.753 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.753 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.753 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.15.k.- Horizontal scan 0.806 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.9.l): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, fs = 45.0 m/s.

VII.188

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.806 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.806 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.806 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.806 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.15.l.- Horizontal scan 0.858 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.9.m): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, 

fs = 45.0 m/s.

VII.189

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.858 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.858 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.858 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.858 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.15.m.- Horizontal scan 0.911 z/H below a 3.5-inch backward-facing step (compares to 

Figure VII.9.n): streamwise and vertical velocity skew, flow angle skew and Reynolds stress, 

fs = 45.0 m/s.

VII.190

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.911 z/H

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.911 z/H

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.911 z/H

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.911 z/H

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.16.a.- Vertical scan 0.525-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity components, number of accepted signal bursts, and statistical 

stationarity convergence standard deviation.

VII.191

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 0.525 x/H 3.5-inch step

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 0.525 x/H 3.5-inch step

Vertical distance, step height

U-component standard deviation, σ /fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 X = 0.525 x/H 1.5-inch step

 X = 0.525 x/H 3.5-inch step

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 X = 0.525 x/H 1.5-inch step

 X = 0.525 x/H 3.5-inch step

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H 1.5-inch step

 14x22 LV: X = 0.525 x/H 3.5-inch step

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H 1.5-inch step

 14x22 LV: X = 0.525 x/H 3.5-inch step

Vertical distance, step height

V-component standard deviation, σ /fs, percent
Figure VII.16.b.- Vertical scan 0.787-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity components, number of accepted signal bursts, and statistical 

stationarity convergence standard deviation.

VII.192

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 0.787 x/H 3.5-inch step

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 0.787 x/H 3.5-inch step

Vertical distance, step height

U-component standard deviation, σ /fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 X = 0.787 x/H 1.5-inch step

 X = 0.787 x/H 3.5-inch step

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 X = 0.787 x/H 1.5-inch step

 X = 0.787 x/H 3.5-inch step

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H 1.5-inch step

 14x22 LV: X = 0.787 x/H 3.5-inch step

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H 1.5-inch step

 14x22 LV: X = 0.787 x/H 3.5-inch step

Vertical distance, step height

V-component standard deviation, σ /fs, percent
Figure VII.16.c.- Vertical scan 1.050-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity components, number of accepted signal bursts, and statistical 

stationarity convergence standard deviation.

VII.193

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 1.050 x/H 3.5-inch step

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 1.050 x/H 3.5-inch step

Vertical distance, step height

U-component standard deviation, σ /fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 X = 1.050 x/H 1.5-inch step

 X = 1.050 x/H 3.5-inch step

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 X = 1.050 x/H 1.5-inch step

 X = 1.050 x/H 3.5-inch step

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H 1.5-inch step

 14x22 LV: X = 1.050 x/H 3.5-inch step

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H 1.5-inch step

 14x22 LV: X = 1.050 x/H 3.5-inch step

Vertical distance, step height

V-component standard deviation, σ /fs, percent
Figure VII.16.d.- Vertical scan 1.312-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity components, number of accepted signal bursts, and statistical 

stationarity convergence standard deviation.

VII.194

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.312 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 1.312 x/H 3.5-inch step

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.312 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 1.312 x/H 3.5-inch step

Vertical distance, step height

U-component standard deviation, σ /fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 X = 1.312 x/H 1.5-inch step

 X = 1.312 x/H 3.5-inch step

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 X = 1.312 x/H 1.5-inch step

 X = 1.312 x/H 3.5-inch step

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H 1.5-inch step

 14x22 LV: X = 1.313 x/H 3.5-inch step

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H 1.5-inch step

 14x22 LV: X = 1.313 x/H 3.5-inch step

Vertical distance, step height

V-component standard deviation, σ /fs, percent
Figure VII.16.e.- Vertical scan 1.575-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity components, number of accepted signal bursts, and statistical 

stationarity convergence standard deviation.

VII.195

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 1.575 x/H 3.5-inch step

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 1.575 x/H 3.5-inch step

Vertical distance, step height

U-component standard deviation, σ /fs, percent

1.0

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

 X = 1.575 x/H 1.5-inch step

 X = 1.575 x/H 3.5-inch step

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 X = 1.575 x/H 1.5-inch step

 X = 1.575 x/H 3.5-inch step

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H 1.5-inch step

 14x22 LV: X = 1.575 x/H 3.5-inch step

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H 1.5-inch step

 14x22 LV: X = 1.575 x/H 3.5-inch step

Vertical distance, step height

V-component standard deviation, σ /fs, percent
Figure VII.16.f.- Vertical scan 1.837-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity components, number of accepted signal bursts, and statistical 

stationarity convergence standard deviation.

VII.196

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 1.837 x/H 3.5-inch step

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 1.837 x/H 3.5-inch step

Vertical distance, step height

U-component standard deviation, σ /fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 X = 1.837 x/H 1.5-inch step

 X = 1.837 x/H 3.5-inch step

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 X = 1.837 x/H 1.5-inch step

 X = 1.837 x/H 3.5-inch step

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H 1.5-inch step

 14x22 LV: X = 1.837 x/H 3.5-inch step

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H 1.5-inch step

 14x22 LV: X = 1.837 x/H 3.5-inch step

Vertical distance, step height

V-component standard deviation, σ /fs, percent
Figure VII.16.g.- Vertical scan 2.1-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity components, number of accepted signal bursts, and statistical 

stationarity convergence standard deviation.

VII.197

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 2.100 x/H 3.5-inch step

Vertical distance, step height

U-component velocity mean, U/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H 1.5-inch step

 BART LV: X = 0.530 x/H 1.5-inch step

 14x22 LV: X = 2.100 x/H 3.5-inch step

Vertical distance, step height

U-component standard deviation, σ /fs, percent

0 1000 2000 3000 4000 5000 6000 7000 8000

-1.0

-0.5

0.0

0.5

1.0

 X = 2.100 x/H 1.5-inch step

 X = 2.100 x/H 3.5-inch step

Vertical distance, step height

Number of valid signals in the ensemble

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

-1.0

-0.5

0.0

0.5

1.0

 X = 2.100 x/H 1.5-inch step

 X = 2.100 x/H 3.5-inch step

Vertical distance, step height

Convergence - average standard deviation, m/s

-0.3 -0.2 -0.1 0.0 0.1

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H 1.5-inch step

 14x22 LV: X = 2.100 x/H 3.5-inch step

Vertical distance, step height

V-component velocity mean, V/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H 1.5-inch step

 14x22 LV: X = 2.100 x/H 3.5-inch step

Vertical distance, step height

V-component standard deviation, σ /fs, percent
Figure VII.17.a.- Vertical scan 0.525-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: velocity magnitude and flow angle.

VII.198

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H 1.5-inch step

 14x22 LV: X = 0.525 x/H 3.5-inch step

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H 1.5-inch step

 14x22 LV: X = 0.525 x/H 3.5-inch step

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H 1.5-inch step

 14x22 LV: X = 0.525 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H 1.5-inch step

 14x22 LV: X = 0.525 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.17.b.- Vertical scan 0.787-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: velocity magnitude and flow angle.

VII.199

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H 1.5-inch step

 14x22 LV: X = 0.787 x/H 3.5-inch step

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H 1.5-inch step

 14x22 LV: X = 0.787 x/H 3.5-inch step

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H 1.5-inch step

 14x22 LV: X = 0.787 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H 1.5-inch step

 14x22 LV: X = 0.787 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.17.c.- Vertical scan 1.050-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: velocity magnitude and flow angle.

VII.200

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H 1.5-inch step

 14x22 LV: X = 1.050 x/H 3.5-inch step

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H 1.5-inch step

 14x22 LV: X = 1.050 x/H 3.5-inch step

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H 1.5-inch step

 14x22 LV: X = 1.050 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H 1.5-inch step

 14x22 LV: X = 1.050 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.17.d.- Vertical scan 1.313-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: velocity magnitude and flow angle.

VII.201

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H 1.5-inch step

 14x22 LV: X = 1.313 x/H 3.5-inch step

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H 1.5-inch step

 14x22 LV: X = 1.313 x/H 3.5-inch step

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H 1.5-inch step

 14x22 LV: X = 1.313 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H 1.5-inch step

 14x22 LV: X = 1.313 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.17.e.- Vertical scan 1.575-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: velocity magnitude and flow angle.

VII.202

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H 1.5-inch step

 14x22 LV: X = 1.575 x/H 3.5-inch step

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H 1.5-inch step

 14x22 LV: X = 1.575 x/H 3.5-inch step

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H 1.5-inch step

 14x22 LV: X = 1.575 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H 1.5-inch step

 14x22 LV: X = 1.575 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.17.f.- Vertical scan 1.837-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: velocity magnitude and flow angle.

VII.203

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H 1.5-inch step

 14x22 LV: X = 1.837 x/H 3.5-inch step

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H 1.5-inch step

 14x22 LV: X = 1.837 x/H 3.5-inch step

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H 1.5-inch step

 14x22 LV: X = 1.837 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H 1.5-inch step

 14x22 LV: X = 1.837 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.17.g.- Vertical scan 2.1-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: velocity magnitude and flow angle.

VII.204

0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H 1.5-inch step

 14x22 LV: X = 2.100 x/H 3.5-inch step

Vertical distance, st ep height

Velocity magnitude mean, M/fs

0 2 4 6 8 10 12 14 16 18 20 22 24

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H 1.5-inch step

 14x22 LV: X = 2.100 x/H 3.5-inch step

Vertical distan ce, step heig ht

Velocity magnitude standard deviation, σ /fs, percent

-20 0 20 40 60 80 100 120 140 160 180 200 220 240 260

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H 1.5-inch step

 14x22 LV: X = 2.100 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle mean, degrees

0 10 20 30 40 50 60 70 80 90 100 110

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H 1.5-inch step

 14x22 LV: X = 2.100 x/H 3.5-inch step

Vertical distan ce, step h eig ht

Vertical flow angle standard deviation, degrees
Figure VII.18.a.- Vertical scan 0.525-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.205

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H 1.5-inch step

 14x22 LV: X = 0.525 x/H 3.5-inch step

Vertical distance, ste p height

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H 1.5-inch step

 14x22 LV: X = 0.525 x/H 3.5-inch step

Vertical distance, step he igh t

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H 1.5-inch step

 14x22 LV: X = 0.525 x/H 3.5-inch step

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.525 x/H 1.5-inch step

 14x22 LV: X = 0.525 x/H 3.5-inch step

Vertical d istance, step he ight

Reynolds stress, m/s2 2
Figure VII.18.b.- Vertical scan 0.787-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.206

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H 1.5-inch step

 14x22 LV: X = 0.787 x/H 3.5-inch step

Vertical distance, st ep height

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H 1.5-inch step

 14x22 LV: X = 0.787 x/H 3.5-inch step

Vertical distan ce, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H 1.5-inch step

 14x22 LV: X = 0.787 x/H 3.5-inch step

Vertical dista nce, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 0.787 x/H 1.5-inch step

 14x22 LV: X = 0.787 x/H 3.5-inch step

Ve rtical distan ce, step height

Reynolds stress, m/s2 2
Figure VII.18.c.- Vertical scan 1.050-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.207

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H 1.5-inch step

 14x22 LV: X = 1.050 x/H 3.5-inch step

Vertical distance, step height

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H 1.5-inch step

 14x22 LV: X = 1.050 x/H 3.5-inch step

Vertical distan ce, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H 1.5-inch step

 14x22 LV: X = 1.050 x/H 3.5-inch step

Vertical dista nce, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.050 x/H 1.5-inch step

 14x22 LV: X = 1.050 x/H 3.5-inch step

Ve rtical distan ce, step height

Reynolds stress, m/s2 2
Figure VII.18.d.- Vertical scan 1.312-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.208

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H 1.5-inch step

 14x22 LV: X = 1.313 x/H 3.5-inch step

Vertical distance, step height

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H 1.5-inch step

 14x22 LV: X = 1.313 x/H 3.5-inch step

Vertical distan ce, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H 1.5-inch step

 14x22 LV: X = 1.313 x/H 3.5-inch step

Vertical dista nce, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.313 x/H 1.5-inch step

 14x22 LV: X = 1.313 x/H 3.5-inch step

Ve rtical distan ce, step height

Reynolds stress, m/s2 2
Figure VII.18.e.- Vertical scan 1.575-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.209

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H 1.5-inch step

 14x22 LV: X = 1.575 x/H 3.5-inch step

Vertical distance, ste p heig ht

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H 1.5-inch step

 14x22 LV: X = 1.575 x/H 3.5-inch step

Vertical distance , step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H 1.5-inch step

 14x22 LV: X = 1.575 x/H 3.5-inch step

Vertical distance, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.575 x/H 1.5-inch step

 14x22 LV: X = 1.575 x/H 3.5-inch step

Vertical distance, step height

Reynolds stress, m/s2 2
Figure VII.18.f.- Vertical scan 1.837-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.210

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H 1.5-inch step

 14x22 LV: X = 1.837 x/H 3.5-inch step

Vertical distance, st ep height

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H 1.5-inch step

 14x22 LV: X = 1.837 x/H 3.5-inch step

Vertical distan ce, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H 1.5-inch step

 14x22 LV: X = 1.837 x/H 3.5-inch step

Vertical dista nce, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 1.837 x/H 1.5-inch step

 14x22 LV: X = 1.837 x/H 3.5-inch step

Ve rtical distan ce, step height

Reynolds stress, m/s2 2
Figure VII.18.g.- Vertical scan 2.1-step heights downstream of the 1.5- and 3.5-inch backward-facing 

steps: streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.211

-1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H 1.5-inch step

 14x22 LV: X = 2.100 x/H 3.5-inch step

Vertical distance, st ep height

U-component skew

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H 1.5-inch step

 14x22 LV: X = 2.100 x/H 3.5-inch step

Vertical distan ce, step height

V-component skew

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H 1.5-inch step

 14x22 LV: X = 2.100 x/H 3.5-inch step

Vertical dista nce, step height

Vertical flow angle skew

-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5

-1.0

-0.5

0.0

0.5

1.0

 14x22 LV: X = 2.100 x/H 1.5-inch step

 14x22 LV: X = 2.100 x/H 3.5-inch step

Ve rtical distan ce, step height

Reynolds stress, m/s2 2
Figure VII.19.a.- Horizontal scan 0.313 z/H above the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.212

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.19.b.- Horizontal scan 0.181 z/H above the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.213

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.19.c.- Horizontal scan 0.050 z/H above the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.214

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.19.d.- Horizontal scan 0.090 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.215

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.19.e.- Horizontal scan 0.220 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.216

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.19.f.- Horizontal scan 0.344 z/H below the 1.5- and 3.5-inch backward-facing steps: streamwise 

and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.217

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.19.g.- Horizontal scan 0.475 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.218

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.19.h.- Horizontal scan 0.606 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.219

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.19.i.- Horizontal scan 0.703 z/H below the 1.5- and 3.5-inch backward-facing steps: streamwise 

and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.220

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.19.j.- Horizontal scan 0.755 z/H below the 1.5- and 3.5-inch backward-facing steps: streamwise 

and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.221

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.19.k.- Horizontal scan 0.806 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.222

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.19.l.- Horizontal scan 0.858 z/H below the 1.5- and 3.5-inch backward-facing steps: streamwise 

and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.223

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.19.m.- Horizontal scan 0.911 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.224

0 1 2 3 4

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

U-component velocity mean, U/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

U-component standard deviation, σ U/fs

Distance downstream from step, x/H

0 1 2 3 4

-0.3

-0.2

-0.1

0.0

0.1

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

V-component mean velocity, V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

V-component standard deviation, σ V/fs

Distance downstream from step, x/H

0 1 2 3 4

0

1000

2000

3000

4000

5000

6000

7000

8000

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

Number of valid signals in the ensemble

Distance downstream from step, x/H

0 1 2 3 4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

Convergence - average standard deviation, m/s

Distance downstream from step, x/H
Figure VII.20.a.- Horizontal scan 0.313 z/H above the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.225

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.20.b.- Horizontal scan 0.181 z/H above the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.226

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.20.c.- Horizontal scan 0.050 z/H above the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.227

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.20.d.- Horizontal scan 0.090 z/H below the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.228

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.20.e.- Horizontal scan 0.220 z/H below the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.229

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.20.f.- Horizontal scan 0.344 z/H below the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.230

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.20.g.- Horizontal scan 0.475 z/H below the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.231

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.20.h.- Horizontal scan 0.606 z/H below the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.232

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.20.i.- Horizontal scan 0.703 z/H below the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.233

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.20.j.- Horizontal scan 0.755 z/H below the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.234

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.20.k.- Horizontal scan 0.806 z/H below the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.235

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.20.l.- Horizontal scan 0.858 z/H below the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.236

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.20.m.- Horizontal scan 0.911 z/H below the 1.5- and 3.5-inch backward-facing steps: velocity 

magnitude and flow angle.

VII.237

0 1 2 3 4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

Velocity magnitudemean, M/fs

Distance downstream from step, x/H

0 1 2 3 4

0

2

4

6

8

10

12

14

16

18

20

22

24

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

Velocity magnitude standarddeviation, σ /fs

Distance downstream from step, x/H

0 1 2 3 4

-20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

Verticalflow angle mean, degrees

Distance downstream from step, x/H

0 1 2 3 4

0

10

20

30

40

50

60

70

80

90

100

110

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

Vertical flow anglestandard deviation, degrees

Distance downstream from step, x/H
Figure VII.21.a.- Horizontal scan 0.313 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.238

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = 0.313 z/H 1.5-inch step

 14x22 LV: Z = 0.312 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.21.b.- Horizontal scan 0.181 z/H above the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.239

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = 0.181 z/H 1.5-inch step

 14x22 LV: Z = 0.181 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.21.c.- Horizontal scan 0.050 z/H above the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.240

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = 0.050 z/H 1.5-inch step

 14x22 LV: Z = 0.050 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.21.d.- Horizontal scan 0.090 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.241

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.090 z/H 1.5-inch step

 14x22 LV: Z = -0.081 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.21.e.- Horizontal scan 0.220 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.242

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.220 z/H 1.5-inch step

 14x22 LV: Z = -0.213 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.21.f.- Horizontal scan 0.344 z/H below the 1.5- and 3.5-inch backward-facing steps: streamwise 

and vertical velocity skew, flow angle skew and Reynolds stress.

VII.243

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.344 z/H 1.5-inch step

 14x22 LV: Z = -0.344 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.21.g.- Horizontal scan 0.475 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.244

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.475 z/H 1.5-inch step

 14x22 LV: Z = -0.475 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.21.h.- Horizontal scan 0.606 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.245

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.606 z/H 1.5-inch step

 14x22 LV: Z = -0.606 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.21.i.- Horizontal scan 0.703 z/H below the 1.5- and 3.5-inch backward-facing steps: streamwise 

and vertical velocity skew, flow angle skew and Reynolds stress.

VII.246

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.703 z/H 1.5-inch step

 14x22 LV: Z = -0.701 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.21.j.- Horizontal scan 0.755 z/H below the 1.5- and 3.5-inch backward-facing steps: streamwise 

and vertical velocity skew, flow angle skew and Reynolds stress.

VII.247

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.755 z/H 1.5-inch step

 14x22 LV: Z = -0.753 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.21.k.- Horizontal scan 0.806 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.248

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.806 z/H 1.5-inch step

 14x22 LV: Z = -0.806 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.21.l.- Horizontal scan 0.858 z/H below the 1.5- and 3.5-inch backward-facing steps: streamwise 

and vertical velocity skew, flow angle skew and Reynolds stress.

VII.249

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.858 z/H 1.5-inch step

 14x22 LV: Z = -0.858 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.21.m.- Horizontal scan 0.911 z/H below the 1.5- and 3.5-inch backward-facing steps: 

streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.250

0 1 2 3 4

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

U-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

V-component skew

Distance downstream from step, x/H

0 1 2 3 4

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

2.0

2.4

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

Flow angleskew

Distance downstream from step, x/H

0 1 2 3 4

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

 14x22 LV: Z = -0.911 z/H 1.5-inch step

 14x22 LV: Z = -0.911 z/H 3.5-inch step

Distance downstream from step, x/H

Reynolds stress, m /s 2 2
Figure VII.22.a.- Crossflow scans through a wing-tip vortex flow, wing angle of attack = 8.0 degrees: 

streamwise and vertical velocity components, number of accepted signal bursts, and statistical stationarity 

convergence standard deviation.

VII.251

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

15.5

16.0

16.5

17.0

17.5

18.0

18.5

19.0

19.5

20.0

20.5

21.0

U -compone nt ve locity mean, m/s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

U-component standarddeviation, m/s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

-7

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

7

V-component velocity mean, m/s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

V-component standarddeviation, m/s

Crossflow distance, inch

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

0

1000

2000

3000

4000

5000

6000

7000

8000

Numb er of mea sured sign als

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Convergence - average stand ard de viation, m/s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625
Figure VII.22.b.- Crossflow scans through a wing-tip vortex flow, wing angle of attack = 20.0 degrees as 

compared to 8.0 degrees: streamwise and vertical velocity components, number of accepted signal 

bursts, and statistical stationarity convergence standard deviation.

VII.252

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

15.5

16.0

16.5

17.0

17.5

18.0

18.5

19.0

19.5

20.0

20.5

21.0

U-comp onent mea n, m/s

Crossflow distance, inch

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

U-component standarddeviation, m/s

Crossflow distance, inch

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

-7

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

7

V-component mean, m/s

Crossflow distance, inch

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

V-component standarddeviation, m/s

Crossflow distance, inch

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Convergence - average stand ard de viation, m/s

Crossflow distance, inch

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

0

1000

2000

3000

4000

5000

6000

7000

8000

Numb er of mea sured sign als

Crossflow distance, inch
Figure VII.22.c.- Crossflow scans through the wake region, wing angle of attack = 8.0 degrees as 

compared to the scan through the vortex: streamwise and vertical velocity components, number of 

accepted signal bursts, and statistical stationarity convergence standard deviation.

VII.253

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

15.5

16.0

16.5

17.0

17.5

18.0

18.5

19.0

19.5

20.0

20.5

21.0

U-comp onent mea n, m/s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

U-component standarddeviation, m/s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

-7

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

7

V-component mean, m/s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

V-component standarddeviation, m/s

Crossflow distance, inch

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

0

1000

2000

3000

4000

5000

6000

7000

8000

Numb er of mea sured sign als

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Convergence - average stand ard de viation, m/s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625
Figure VII.23.a.- Crossflow scans through a wing-tip vortex flow, wing angle of attack = 8.0 degrees: 

velocity magnitude and flow angle.

VII.254

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

15.5

16.0

16.5

17.0

17.5

18.0

18.5

19.0

19.5

20.0

20.5

21.0

21.5

22.0

Ve locity m agnitude mea n, m/s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

Velocity magnitudestandard deviation, m/s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

-20

-15

-10

-5

0

5

10

15

20

Flow angle me an, de gree s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Flow angle standarddeviation, degrees

Crossflow distance, inch
Figure VII.23.b.- Crossflow scans through a wing-tip vortex flow, wing angle of attack = 20.0 degrees as 

compared to 8.0 degrees: velocity magnitude and flow angle.

VII.255

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

15.5

16.0

16.5

17.0

17.5

18.0

18.5

19.0

19.5

20.0

20.5

21.0

21.5

22.0

Ve locity m agnitude mea n, m/s

Crossflow distance, inch

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

Velocity magnitudestandard deviation, m/s

Crossflow distance, inch

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

-20

-15

-10

-5

0

5

10

15

20

Flow angle me an, de gree s

Crossflow distance, inch

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Flow angle standarddeviation, degrees

Crossflow distance, inch
Figure VII.23.c.- Crossflow scans through the wake region, wing angle of attack = 8.0 degrees as 

compared to the scan through the vortex: velocity magnitude and flow angle.

VII.256

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

15.5

16.0

16.5

17.0

17.5

18.0

18.5

19.0

19.5

20.0

20.5

21.0

21.5

22.0

Ve locity m agnitude mea n, m/s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

Velocity magnitudestandard deviation, m/s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

-20

-15

-10

-5

0

5

10

15

20

Flow angle me an, de gree s

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Flow angle standarddeviation, degrees

Crossflow distance, inch
Figure VII.24.a.- Crossflow scans through a wing-tip vortex flow, wing angle of attack = 8.0 degrees: 

streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.257

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-5.0

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

U -compon ent ske w

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-5.5

-5.0

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

V-compon ent ske w

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

R eynolds stress, m 2/s2

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.8 -2.4 -2.0 -1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Flow angle ske w

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 1/28/2011 X = 45.75, Z = -0.625

 2/2/2011 X = 45.75, Z = -0.625

 2/3/2011 X = 45.75, Z = -0.625
Figure VII.24.b.- Crossflow scans through a wing-tip vortex flow, wing angle of attack = 20.0 degrees as 

compared to 8.0 degrees: streamwise and vertical velocity skew, flow angle skew and Reynolds stress.

VII.258

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

-5.0

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

U -compon ent ske w

Crossflow distance, inch

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

-5.5

-5.0

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

V-compon ent ske w

Crossflow distance, inch

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Flow angle ske w

Crossflow distance, inch

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

R eynolds stress, m 2/s2

Crossflow distance, inch

Wing tip location, AoA = 20.0 degrees

X = -0.21, Y = 0.83

Origin = Wing tip, trailing edge

X = 45.75, Z = -0.625

 2/3/2011 AoA = 20.0 degrees

 2/9/2011 AoA = 20.0 degrees

 2/3/2011 AoA = 8.0 degrees
Figure VII.24.c.- Crossflow scans through the wake region, wing angle of attack = 8.0 degrees as 

compared to the scan through the vortex: streamwise and vertical velocity skew, flow angle skew and 

Reynolds stress.

VII.259

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

-5.0

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

U -compon ent ske w

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

-5.5

-5.0

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

Wing tip location, AoA = 20.0 degrees

X = -0.21, Z = -0.83

V-compon ent ske w

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

R eynolds stress, m 2/s2

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625

-3.2 -2.4 -1.6 -0.8 0.0 0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4

-4.5

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

Flow angle ske w

Crossflow distance, inch

Origin = Wing tip, trailing edge

AoA = 8.0 degrees

 2/4/2011 X = 45.75, Z = -5.625

 2/9/2011 X = 45.75, Z = -6.530

 2/3/2011 X = 45.75, Z = -0.625
Figure VII.25.a.- Zoom lens focal distance as a function of negative lens traverse position.

Figure VII.25.b.- Cross-beam angle as a function of negative lens traverse position.

VII.260

0 1 2 3 4 5 6 7 8

75

100

125

150

175

200

225

250

275

300

325 Data: Data1_B

Model: ExpGro1

Equation: y = A1*exp(x/t1) + y0

Weighting: 

y No weighting

Chi^2/DoF = 7.48867

R^2 = 0.99967

y0 95.24588 ±4.63474

A1 13.81049 ±2.71094

t1 2.88404 ±0.19168

 Test 032311

 Exponential fit

Focal distance, inches

Negative lens traverse position, inch

0 1 2 3 4 5 6 7 8

1

2

3

4

5

6

7

 Test 032311

 -0.566 X + 6.256

Crossbeamangle, degrees

Negative lens traverse position, inch
Figure VII.25.c.- Zoom lens focal distance as a function of lens separation.

Figure VII.25.d.- Cross-beam angle as a function of lens separation.

VII.261

17 18 19 20 21 22 23 24 25 26 27

75

100

125

150

175

200

225

250

275

300

325 Data: Data2_B

Model: ExpGro1

Equation: y = A1*exp(x/t1) + y0

Weighting: 

y No weighting

Chi^2/DoF = 7.5562

R^2 = 0.99966

y0 95.26998 ±4.65231

A1 0.02279 ±0.01423

t1 2.88249 ±0.1924

 Test 032311

 Exponential fit

Focal distance, inch

Lens separation distance (inside first surfaces), inch

17 18 19 20 21 22 23 24 25 26 27

1

2

3

4

5

6

7

 Test 032311

 -0.566 X +16.703

Cross beam angle, degrees

Lens separation distance (inside first surfaces), inch
Figure VII.25.e.- Peak signal level distribution as a function of focal length - U-component.

VII.262

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

100

200

300

400

500

600

700

800

900

1000

Num ber of s ignal bursts

Peak signal level, V

 Focal length = 9.0 feet

 Focal length = 10.5 feet

 Focal length = 15.0 feet

 Focal length = 25.0 feet

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

100

200

300

400

500

600

700

800

900

1000

Num ber of s ignal bursts

Peak signal level, V

 Focal length = 9.0 feet

 Focal length = 10.5 feet

 Focal length = 15.0 feet

 Focal length = 25.0 feet

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

100

200

300

400

500

600

700

800

900

1000

N um ber of signal bursts

Peak signal level, V

 Focal length = 9.0 feet

 Focal length = 10.5 feet

 Focal length = 15.0 feet

 Focal length = 25.0 feet

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

100

200

300

400

500

600

700

800

900

1000

N um ber of signal bursts

Peak signal level, V

 Focal length = 9.0 feet

 Focal length = 10.5 feet

 Focal length = 15.0 feet

 Focal length = 25.0 feet
Figure VII.25.f.- Peak signal level distribution as a function of focal length - V-component.

VII.263

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

100

200

300

400

500

600

Number of signal bursts

Peak signal level, V

 Focal length = 9.0 feet

 Focal length = 10.5 feet

 Focal length = 15.0 feet

 Focal length = 25.0 feet

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

100

200

300

400

500

600

Number of signal bursts

Peak signal level, V

 Focal length = 9.0 feet

 Focal length = 10.5 feet

 Focal length = 15.0 feet

 Focal length = 25.0 feet

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

100

200

300

400

500

600

Number of signal bursts

Peak signal level, V

 Focal length = 9.0 feet

 Focal length = 10.5 feet

 Focal length = 15.0 feet

 Focal length = 25.0 feet

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

100

200

300

400

500

600

Number of signal bursts

Peak signal level, V

 Focal length = 9.0 feet

 Focal length = 10.5 feet

 Focal length = 15.0 feet

 Focal length = 25.0 feet
Figure VII.26.a.- Zoom lens focal distance as a function of negative lens traverse position - repeat.

Figure VII.26.b.- Cross-beam angle as a function of negative lens traverse position - repeat.

VII.264

0 1 2 3 4 5 6 7 8

1

2

3

4

5

6

7

 Test 042111

 Test 042811

 -0.578 X + 6.258

Crossbeamangle, degrees

Negative lens traverse position, inch

0 1 2 3 4 5 6 7 8

75

100

125

150

175

200

225

250

275

300

325 Data: Test042111_B

Model: ExpGro1

Equation: y = A1*exp(x/t1) + y0

Weighting: 

y No weighting

Chi^2/DoF = 11.8808

R^2 = 0.99825

y0 100.48426 ±4.47138

A1 11.38099 ±1.89148

t1 2.67429 ±0.1393

 Test 042111

 Test 042811

 Exponential fit

Focal length, inches

Negative lens traverse position, inch
Figure VII.26.c.- Zoom lens focal distance as a function of lens separation - repeat.

Figure VII.26.d.- Cross-beam angle as a function of lens separation - repeat.

VII.265

17 18 19 20 21 22 23 24 25 26 27

1

2

3

4

5

6

7

 Test 042111

 Test 042811

 -0.578 X + 16.995

Cross beam angle, degrees

Lens separation distance (inside first surfaces), inch

17 18 19 20 21 22 23 24 25 26 27

75

100

125

150

175

200

225

250

275

300

325 Data: Data1_B

Model: ExpGro1

Equation: y = A1*exp(x/t1) + y0

Weighting: 

y No weighting

Chi^2/DoF = 11.8808

R^2 = 0.99825

y0 100.48426 ±4.47138

A1 0.01092 ±0.00576

t1 2.67429 ±0.1393

 Test 042111

 Test 042811

 Exponential fit

Focal length, inches

Lens separation distance (inside first surfaces), inch
Figure VII.26.e.- Negative lens traverse position as a function of zoom lens focal distance.

Figure VII.26.f.- Negative lens traverse position as a function of cross-beam angle.

VII.266

75 100 125 150 175 200 225 250 275 300 325

0

1

2

3

4

5

6

7

8

Data: Data1_B

Model: ExpDec1

Equation: y = A1*exp(-x/t1) + y0

Weighting: 

y No weighting

Chi^2/DoF = 0.01292

R^2 = 0.99846

y0 8.2371±0.12446

A1 -34.55675 ±2.11904

t1 74.59275 ±3.41035

 Test 042111

 Test 042811

 Exponential fit

Negative lens traverse position, inch

Focal length, inches

1 2 3 4 5 6 7

0

1

2

3

4

5

6

7

8

 Test 042111

 Test 042811

 -1.731 X + 10.830

Negative lens traverse position, inch

Cross-beam angle, degrees
Figure VII.27.a.- Measurement volume diameter based on measured velocity magnitude and transit time 

from the ±1/e2 amplitudes on the captured signal.

Figure VII.27.b.- Measurement volume length as a function of focal length: measured length based on 

signals reduced to 80% of peak, theoretical length based on ±1/e2 locations.

VII.267

75 100 125 150 175 200 225 250 275 300 325

50

75

100

125

150

175

200

225

250

275

300

 Theory

 Measured

Measurement volume diameter, microns

Focal length, inches

75 100 125 150 175 200 225 250 275 300 325

0

5

10

15

20

25

30

Data: Data5_C

Model: ExpGro1

Equation: y = A1*exp(x/t1) + y0

Weighting: 

y No weighting

Chi^2/DoF = 1.55838

R^2 = 0.98581

y0 -0.71839 ±3.30588

A1 0.81078 ±1.01947

t1 98.98543 ±34.24479

 Theory

 Threshold @ 80% of peak

 Exponential curve fit

Measurement volume length, mm

Focal length, inches
Figure VII.27.c.- Measurement volume length as a function of focal length: measured length based on 

signals reduced to 50% of peak, theoretical length based on ±1/e2 locations.

VII.268

75 100 125 150 175 200 225 250 275 300 325

0

5

10

15

20

25

30

Data: Data5_D

Model: ExpGro1

Equation: y = A1*exp(x/t1) + y0

Weighting: 

y No weighting

Chi^2/DoF = 0.28839

R^2 = 0.99919

y0 -17.19346 ±9.25461

A1 11.68163 ±7.16636

t1 244.52649 ±75.51788

 Theory

 Threshold @ 50% of peak

 Exponential curve fit

Measurement volume length, mm

Focal length, inches
Figure VII.28.a.- Average signal-to-noise ratios of the signal bursts contained within each measurement 

ensemble as each surface is moved toward the measurement volume – Focal distance: 120 inches, 

particle size: 1.0 micron PSL, laser power: 0.5 W all-lines.

Figure VII.28.b.- Average signal-to-noise ratios of the signal bursts contained within each measurement 

ensemble as each surface is moved toward the measurement volume – Focal distance: 180 inches, 

particle size: 1.0 micron PSL, laser power: 0.5 W all-lines.

VII.269

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20 Flat Black

 Aluminum

 Semi Gloss

 Aeroglaze

 ChemGlaze

 Rhodamine B

 Nanotube

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Error bars = standard deviation

Threshold

0.1 1 10

0

5

10

15

20

25

30

35

40

Error bars = standard deviation

 Flat Black

 Aluminum

 Semi Gloss

 Aeroglaze

 ChemGlaze

 Rhodamine B

 Nanotube

Signal-to-noise ratio

Distance of measurement volume to surface, inch

V-component (514.5 nm)

Threshold

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

Error bars = standard deviation

 Flat Black

 Aluminum

 Semi Gloss

 Aeroglaze

 ChemGlaze

 Rhodamine B

 Nanotube

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Threshold

0.1 1 10

0

5

10

15

20

25

30

35

40

Error bars = standard deviation

 Flat Black

 Aluminum

 Semi Gloss

 Aeroglaze

 ChemGlaze

 Rhodamine B

 Nanotube

Signal-to-noise ratio

Distance of measurement volume to surface, inch

V-component (514.5 nm)

Threshold
Figure VII.28.c.- Average signal-to-noise ratios of the signal bursts contained within each measurement 

ensemble as each surface is moved toward the measurement volume – Focal distance: 228 inches, 

particle size: 1.0 micron PSL, laser power: 0.5 W all-lines.

Figure VII.28.d.- Average signal-to-noise ratios of the signal bursts contained within each measurement 

ensemble as each surface is moved toward the measurement volume – Focal distance: 276 inches, 

particle size: 1.0 micron PSL, laser power: 1.0 W all-lines.

VII.270

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

Error bars = standard deviation

 Flat Black

 Aluminum

 Semi Gloss

 Aeroglaze

 ChemGlaze

 Rhodamine B

 Nanotube

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Threshold

0.1 1 10

0

5

10

15

20

25

30

35

40

Error bars = standard deviation

 Flat Black

 Aluminum

 Semi Gloss

 Aeroglaze

 ChemGlaze

 Rhodamine B

 Nanotube

Signal-to-noise ratio

Distance of measurement volume to surface, inch

V-component (514.5 nm)

Threshold

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

Error bars = standard deviation

 Flat Blace

 Aluminum

 Semi Gloss

 Aeroglaze

 ChemGlaze

 Rhadamine B

 Nanotube

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Threshold

0.1 1 10

0

5

10

15

20

25

30

35

40

Error bars = standard deviation

 Flat Black

 Aluminum

 Semi Gloss

 Aeroglaze

 ChemGlaze

 Rhodamine B

 Nanotube

Signal-to-noise ratio

Distance of measurement volume to surface, inch

V-component (514.5 nm)

Threshold
Figure VII.29.a.- Average signal-to-noise ratios of the signal bursts contained within each measurement 

ensemble as each surface is moved toward the measurement volume – Flat black, particle size: 

1.0 micron PSL.

Figure VII.29.b.- Average signal-to-noise ratios of the signal bursts contained within each measurement 

ensemble as each surface is moved toward the measurement volume – Unpainted aluminum plate, 

particle size: 1.0 micron PSL.

VII.271

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

 FD = 120 inches

 FD = 180 inches

 FD = 228 inches

 FD = 276 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Error bars = Standard Deviation

Threshold

20 deg tilt

0.1 1 10

0

5

10

15

20

25

30

35

40

Threshold Error bars = Standard Deviation

V-component (514.5 nm)

 FD = 120 inches

 FD = 180 inches

 FD = 228 inches

 FD = 276 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch

20 deg tilt

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

 FD = 120 inches

 FD = 180 inches

 FD = 228 inches

 FD = 276 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Error bars = Standard Deviation

Threshold

3 deg tilt

30 deg tilt

25 deg tilt

15 deg tilt 30 deg tilt

0.1 1 10

0

5

10

15

20

25

30

35

40

Threshold Error bars = Standard Deviation

V-component (514.5 nm)

 FD = 120 inches

 FD = 180 inches

 FD = 228 inches

 FD = 276 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch

3 deg tilt

30 deg tilt

25 deg tilt

15 deg tilt

30 deg tilt
Figure VII.29.c.- Average signal-to-noise ratios of the signal bursts contained within each measurement 

ensemble as each surface is moved toward the measurement volume – Semi-gloss black paint, particle 

size: 1.0 micron PSL.

Figure VII.29.d.- Average signal-to-noise ratios of the signal bursts contained within each measurement 

ensemble as each surface is moved toward the measurement volume – Aeroglaze, particle size: 

1.0 micron PSL.

VII.272

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

 FD = 120 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Error bars = Standard Deviation

Threshold

0.1 1 10

0

5

10

15

20

25

30

35

40

Threshold Error bars = Standard Deviation

V-component (514.5 nm)

 FD = 120 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

 FD = 120 inches

 FD = 180 inches

 FD = 228 inches

 FD = 276 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Error bars = Standard Deviation

Threshold

0.1 1 10

0

5

10

15

20

25

30

35

40

Threshold Error bars = Standard Deviation

V-component (514.5 nm)

 FD = 120 inches

 FD = 180 inches

 FD = 228 inches

 FD = 276 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch
Figure VII.29.e.- Average signal-to-noise ratios of the signal bursts contained within each measurement 

ensemble as each surface is moved toward the measurement volume – Chem Glaze sample, particle 

size: 1.0 micron PSL.

Figure VII.29.f.- Average signal-to-noise ratios of the signal bursts contained within each measurement 

ensemble as each surface is moved toward the measurement volume – Semi gloss black paint with 

Rhodamine B added, particle size: 1.0 micron PSL.

VII.273

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

10 deg tilt

25 deg tilt

Slight angle down

 FD = 120 inches

 FD = 180 inches

 FD = 228 inches

 FD = 276 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Error bars = Standard Deviation

Threshold

0.1 1 10

0

5

10

15

20

25

30

35

40

Threshold Error bars = Standard Deviation

V-component (514.5 nm)

 FD = 120 inches

 FD = 180 inches

 FD = 228 inches

 FD = 276 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch

Slight angle down

25 deg tilt

10 deg tilt

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

 FD = 120 inches

 FD = 180 inches

 FD = 228 inches

 FD = 276 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Error bars = Standard Deviation

Threshold

0.1 1 10

0

5

10

15

20

25

30

35

40

Threshold Error bars = Standard Deviation

V-component (514.5 nm)

 FD = 120 inches

 FD = 180 inches

 FD = 228 inches

 FD = 276 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch
Figure VII.29.g.- Average signal-to-noise ratios of the signal bursts contained within each measurement 

ensemble as each surface is moved toward the measurement volume – Nanotube matrix sample, particle 

size: 1.0 micron PSL.

Figure VII.29.h.- Average signal-to-noise ratios of the signal bursts contained within each measurement 

ensemble as each surface is moved toward the measurement volume – Nanotube matrix sample: normal 

surface versus damaged surface, particle size: 1.0 micron PSL.

VII.274

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

 FD = 120 inches

 FD = 180 inches

 FD = 228 inches

 FD = 276 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Error bars = Standard Deviation

Threshold

0.1 1 10

0

5

10

15

20

25

30

35

40

Threshold Error bars = Standard Deviation

V-component (514.5 nm)

 FD = 120 inches

 FD = 180 inches

 FD = 228 inches

 FD = 276 inches

Signal-to-noise ratio

Distance of measurement volume to surface, inch

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

FD = 276 inches

 Nanotube - original

 Nanotube -smeared

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Error bars = Standard Deviation

Threshold

0.1 1 10

0

5

10

15

20

25

30

35

40

FD = 276 inches

Threshold Error bars = Standard Deviation

V-component (514.5 nm)

 Nanotube - original

 Nanotube - smeared

Signal-to-noise ratio

Distance of measurement volume to surface, inch
Figure VII.30.a.(1) - Velocity statistics as each surface is moved toward the measurement volume – Flat 

black sample, Focal distance = 120 inches.

VII.275

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Flat Black

Focal Distance = 120 inches

June 16, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Flat Black

Focal Distance = 120 inches

June 16, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Flat Black

Focal Distance = 120 inches

June 16, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Flat Black

Focal Distance = 120 inches

June 16, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Flat Black

Focal Distance = 120 inches

June 16, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.30.a.(2)(a) - Velocity histograms obtained at 36-inch separation – Flat black sample, Focal 

distance = 120 inches.

VII.276

 - 10 -5 0 5 10 15

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

U-mean: 1.62 ?U-mean 0.06 Sigma: 2.00

 10 15 20 25 30 35 40

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

Numb er of m easureme nts

V-mean: 20.35 ?V-mean 0.08 Sigma: 2.44

 - 10 -5 0 5 10 15

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

U-mean: 1.62 ?U-mean 0.06 Sigma: 2.02

 10 15 20 25 30 35 40

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

Num ber o f measure ments

V-mean: 20.34 ?V-mean 0.08 Sigma: 2.44

 - 10 -5 0 5 10 15

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

N umber of measurements

U-mean: 1.53 ?U-mean 0.08 Sigma: 2.07

 10 15 20 25 30 35 40

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

N umber of measurements

V-mean: 20.29 ?V-mean 0.09 Sigma: 2.48

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)
Figure VII.30.a.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Flat black sample, 

Focal distance = 120 inches.

VII.277

 - 15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

Numb er of m easureme nts

U-mean: 1.11 ?U-mean 0.09 Sigma: 2.85

 5 10 15 20 25 30 35 40 45

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

Numb er of m easureme nts

V-mean: 19.97 ?V-mean 0.12 Sigma: 3.53

 - 15 -10 -5 0 5 10 15 2 0 25

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

Num ber o f measure ments

U-mean: 1.12 ?U-mean 0.09 Sigma: 2.89

 5 10 15 20 25 30 35 40 45

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

Num ber o f measure ments

V-mean: 20.00 ?V-mean 0.11 Sigma: 3.55

 - 20 -15 -10 -5 0 5 10 1 5 20

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

N umber of measurements

U-mean: 0.94 ?U-mean 0.12 Sigma: 2.87

 5 10 15 20 25 30 35 40 45

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

N umber of measurements

V-mean: 19.46 ?V-mean 0.16 Sigma: 3.64

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)
Figure VII.30.a.(2)(c) - Velocity histograms obtained at closest approach – Flat black sample, Focal 

distance = 120 inches.

VII.278

 - 20 -15 -10 -5 0 5 10 15 20 25

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

Numb er of m easureme nts

U-mean: -0.26 ?U-mean 0.14 Sigma: 3.69

 -15 -10 -5 0 5 10 15 20 25 30 35 4 0 4 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

Numb er of m easureme nts

V-mean: 13.31 ?V-mean 0.18 Sigma: 4.94

 - 25 -20 -15 - 10 -5 0 5 10 15 20 25

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

Num ber o f measure ments

U-mean: -0.58 ?U-mean 0.14 Sigma: 4.20

 -15 -10 -5 0 5 10 15 20 25 30 35 4 0 4 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

Num ber o f measure ments

V-mean: 13.45 ?V-mean 0.17 Sigma: 5.04

 - 20 -15 -10 -5 0 5 10 15 20 25

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

N umber of measurements

U-mean: -0.31 ?U-mean 0.22 Sigma: 3.63

 -15 -10 -5 0 5 10 15 20 25 30 35 4 0

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

N umber of measurements

V-mean: 12.12 ?V-mean 0.29 Sigma: 4.80

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)
Figure VII.30.b.(1) - Velocity statistics as each surface is moved toward the measurement volume – Flat 

black sample, Focal distance = 180 inches.

VII.279

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Flat Black

Focal Distance = 180 inches

July 26, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Flat Black

Focal Distance = 180 inches

July 26, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Flat Black

Focal Distance = 180 inches

July 26, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Flat Black

Focal Distance = 180 inches

July 26, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Flat Black

Focal Distance = 180 inches

July 26, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.30.b.(2)(a) - Velocity histograms obtained at 36-inch separation – Flat black sample, Focal 

distance = 180 inches.

VII.280

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Numb er of m easureme nts

U-mean: -0.07 ?U-mean 0.03 Sigma: 1.03

 4 6 8 10 12 14 16 18 20 22 2 4

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

V-mean: 11.73 ?V-mean 0.06 Sigma: 1.77

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Num ber o f measure ments

U-mean: -0.07 ?U-mean 0.03 Sigma: 1.05

 4 6 8 10 12 14 16 18 20 22 2 4

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

V-mean: 11.73 ?V-mean 0.06 Sigma: 1.77

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

N umber of measurements

U-mean: -0.04 ?U-mean 0.04 Sigma: 1.02

 4 6 8 10 12 14 16 18 20 2 2

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

V-mean: 11.73 ?V-mean 0.06 Sigma: 1.69

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)
Figure VII.30.b.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Flat black sample, 

Focal distance = 180 inches.

VII.281

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Numb er of m easureme nts

U-mean: -0.27 ?U-mean 0.05 Sigma: 1.37

 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

V-mean: 11.87 ?V-mean 0.09 Sigma: 2.47

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Num ber o f measure ments

U-mean: -0.31 ?U-mean 0.05 Sigma: 1.47

 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 11.87 ?V-mean 0.08 Sigma: 2.48

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Number of measurements

U-mean: -0.28 ?U-mean 0.06 Sigma: 1.23

 0 5 10 15 20 25

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Number of measurements

V-mean: 11.99 ?V-mean 0.12 Sigma: 2.30

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)
Figure VII.30.b.(2)(c) - Velocity histograms obtained at closest approach – Flat black sample, Focal 

distance = 180 inches.

VII.282

 -10 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

U-mean: -0.43 ?U-mean 0.07 Sigma: 1.59

 -10 -5 0 5 10 15 20 25 30 35

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

Numb er of m easureme nts

V-mean: 10.91 ?V-mean 0.14 Sigma: 3.13

 -10 -8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: -0.59 ?U-mean 0.08 Sigma: 1.95

 -10 -5 0 5 10 15 20 25 30 35

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

Num ber o f measure ments

V-mean: 10.89 ?V-mean 0.13 Sigma: 3.23

 -10 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Number of measurements

U-mean: -0.42 ?U-mean 0.11 Sigma: 1.60

 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

Number of measurements

V-mean: 10.88 ?V-mean 0.21 Sigma: 2.98

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)
Figure VII.30.c.(1) - Velocity statistics as each surface is moved toward the measurement volume – Flat 

black sample, Focal distance = 228 inches.

VII.283

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Flat Black

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Flat Black

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Flat Black

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Flat Black

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Flat Black

Focal Distance = 228 inches

July 28, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.30.c.(2)(a) - Velocity histograms obtained at 36-inch separation – Flat black sample, Focal 

distance = 228 inches.

VII.284

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

 55

Numb er of measurem ents

U-mean: -0.14 ?U-mean 0.04 Sigma: 1.00

 2 4 6 8 10 12 14 16 18 20

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Numb er of m easureme nts

V-mean: 8.84 ?V-mean 0.06 Sigma: 1.54

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Num ber o f measure ments

U-mean: -0.19 ?U-mean 0.04 Sigma: 1.20

 2 4 6 8 10 12 14 16 18

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Num ber o f measure ments

V-mean: 8.79 ?V-mean 0.05 Sigma: 1.62

 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

 55

N umber of mea suremen ts

U-mean: -0.15 ?U-mean 0.07 Sigma: 0.95

 2 4 6 8 10 12 14 16 18

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

V-mean: 8.85 ?V-mean 0.11 Sigma: 1.45

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)
Figure VII.30.c.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Flat black sample, 

Focal distance = 228 inches.

VII.285

 -8 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

N umber of me asu reme nts

U-mean: -0.19 ?U-mean 0.05 Sigma: 1.10

 2 4 6 8 10 12 14 16 18 20

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

V-mean: 8.82 ?V-mean 0.07 Sigma: 1.54

 - 10 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Num ber o f measure ments

U-mean: -0.35 ?U-mean 0.06 Sigma: 1.59

 2 4 6 8 10 12 14 16 18

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Number of measurements

V-mean: 8.76 ?V-mean 0.06 Sigma: 1.59

 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

 55

N umber of mea suremen ts

U-mean: -0.15 ?U-mean 0.09 Sigma: 0.82

 2 4 6 8 10 12 14 16 18

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

V-mean: 8.91 ?V-mean 0.15 Sigma: 1.44

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)
Figure VII.30.c.(2)(c) - Velocity histograms obtained at closest approach – Flat black sample, Focal 

distance = 228 inches.

VII.286

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Numb er of m easureme nts

U-mean: -0.16 ?U-mean 0.09 Sigma: 1.38

 0 2 4 6 8 10 12 14 16 18

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

V-mean: 7.69 ?V-mean 0.12 Sigma: 1.80

 - 60 -50 -40 -30 -20 -10 0 10 20 30 40 50

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: -5.47 ?U-mean 0.48 Sigma: 10.36

 -10 -5 0 5 10 15 20 25

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Num ber o f measure ments

V-mean: 7.26 ?V-mean 0.12 Sigma: 2.54

 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

 55

N umber of mea suremen ts

U-mean: 0.06 ?U-mean 0.20 Sigma: 0.91

 0 2 4 6 8 10 12 14 16 18

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

V-mean: 8.03 ?V-mean 0.37 Sigma: 1.71

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)
Figure VII.30.d.(1) - Velocity statistics as each surface is moved toward the measurement volume – Flat 

black sample, Focal distance = 276 inches.

VII.287

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Flat Black

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Flat Black

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Flat Black

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Flat Black

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Flat Black

Focal Distance = 276 inches

August 2, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.30.d.(2)(a) - Velocity histograms obtained at 36-inch separation – Flat black sample, Focal 

distance = 276 inches.

VII.288

 - 10 - 8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Numb er of m easureme nts

U-mean: -0.36 ?U-mean 0.10 Sigma: 1.74

 -10 -5 0 5 10 15 20 25

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 4.99 ?V-mean 0.15 Sigma: 2.49

 - 25 -20 -15 -10 -5 0 5 10 15 20 25

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Num ber o f measure ments

U-mean: -2.14 ?U-mean 0.22 Sigma: 4.51

 -10 -5 0 5 10 15 20 25

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 5.28 ?V-mean 0.13 Sigma: 2.66

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

N umber of measurements

U-mean: -0.20 ?U-mean 0.14 Sigma: 1.00

 -10 -5 0 5 10 15 20

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

N umber of measurements

V-mean: 3.72 ?V-mean 0.33 Sigma: 2.33

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)
Figure VII.30.d.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Flat black sample, 

Focal distance = 276 inches.

VII.289

 - 25 -20 -15 - 10 -5 0 5 10 15 20 25

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

Numb er of m easurem ents

U-mean: -1.52 ?U-mean 0.22 Sigma: 3.67

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 5.31 ?V-mean 0.15 Sigma: 2.55

 - 80 -60 -40 - 20 0 20 40 60 80 100 120

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

Nu mber o f measurem ents

U-mean: 10.56 ?U-mean 0.65 Sigma: 17.28

 -15 -10 -5 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 5.56 ?V-mean 0.12 Sigma: 3.14

 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

N umber of mea suremen ts

U-mean: -0.24 ?U-mean 0.17 Sigma: 0.93

 -15 -10 - 5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

N umber of measurements

V-mean: 4.09 ?V-mean 0.45 Sigma: 2.44

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)
Figure VII.30.d.(2)(c) - Velocity histograms obtained at closest approach – Flat black sample, Focal 

distance = 276 inches.

VII.290

 - 80 -60 -40 -20 0 20 40 60 80 100

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Nu mber o f measurem ents

U-mean: 8.26 ?U-mean 1.32 Sigma: 17.01

 -15 -10 -5 0 5 10 15 20 25

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 5.42 ?V-mean 0.22 Sigma: 2.79

 -150 -100 -50 0 50 100 1 50 200

U-component velocity, m/s

 0

 2

 4

 6

 8

Nu mber o f measurem ents

U-mean: 9.89 ?U-mean 0.79 Sigma: 26.94

 -150 -100 -50 0 50 100 150 200

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

Nu mber o f measurem ents

V-mean: 22.69 ?V-mean 0.84 Sigma: 28.68

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

N umber of measurements

U-mean: -0.11 ?U-mean 0.38 Sigma: 1.15

 -15 -10 -5 0 5 10 15 20 25

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

N umber of measurements

V-mean: 4.28 ?V-mean 0.82 Sigma: 2.50

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)
Figure VII.31.a.- Velocity statistics as each surface is moved toward the measurement volume – 

Unpainted aluminum sample, Focal distance = 120 inches.

VII.291

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Aluminum Plate

Focal Distance = 120 inches

July 14, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Aluminum Plate

Focal Distance = 120 inches

July 14, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Aluminum Plate

Focal Distance = 120 inches

July 14, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Aluminum Plate

Focal Distance = 120 inches

July 14, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Aluminum Plate

Focal Distance = 120 inches

July 14, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.31.b.- Velocity statistics as each surface is moved toward the measurement volume – 

Unpainted aluminum sample, Focal distance = 180 inches.

VII.292

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Aluminum Plate

Focal Distance = 180 inches

July 27, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Aluminum Plate

Focal Distance = 180 inches

July 27, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Aluminum Plate

Focal Distance = 180 inches

July 27, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Aluminum Plate

Focal Distance = 180 inches

July 27, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Aluminum Plate

Focal Distance = 180 inches

July 27, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.31.c.- Velocity statistics as each surface is moved toward the measurement volume – 

Unpainted aluminum sample, Focal distance = 228 inches.

VII.293

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Aluminum Plate

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Aluminum Plate

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Aluminum Plate

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Aluminum Plate

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Aluminum Plate

Focal Distance = 228 inches

July 28, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.31.d.- Velocity statistics as each surface is moved toward the measurement volume – 

Unpainted aluminum sample, Focal distance = 276 inches.

VII.294

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Aluminum Plate

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Aluminum Plate

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Aluminum Plate

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Aluminum Plate

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Aluminum Plate

Focal Distance = 276 inches

August 2, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.32.- Velocity statistics as each surface is moved toward the measurement volume – Semi gloss 

black paint sample, Focal distance = 120 inches.

VII.295

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Semi Gloss

Focal Distance = 120 inches

June 17, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Semi Gloss

Focal Distance = 120 inches

June 17, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Semi Gloss

Focal Distance = 120 inches

June 17, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Semi Gloss

Focal Distance = 120 inches

June 17, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Semi Gloss

Focal Distance = 120 inches

June 17, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.33.a.(1) - Velocity statistics as each surface is moved toward the measurement volume – 

Aeroglaze, Focal distance = 120 inches.

VII.296

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Aeroglaze

Focal Distance = 120 inches

June 16, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Aeroglaze

Focal Distance = 120 inches

June 16, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Aeroglaze

Focal Distance = 120 inches

June 16, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Aeroglaze

Focal Distance = 120 inches

June 16, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Aeroglaze

Focal Distance = 120 inches

June 16, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.33.a.(2)(a) - Velocity histograms obtained at 36-inch separation – Aeroglaze, Focal 

distance = 120 inches.

VII.297

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 20 -15 -10 -5 0 5 10 15 20 25

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

Numb er of m easureme nts

U-mean: 0.12 ?U-mean 0.12 Sigma: 3.65

 -15 -10 -5 0 5 10 15 20 25 30 35 40 45

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

Numb er of m easureme nts

V-mean: 13.69 ?V-mean 0.16 Sigma: 4.97

 - 20 -15 -10 -5 0 5 10 15 20 25

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

Num ber o f measure ments

U-mean: 0.11 ?U-mean 0.12 Sigma: 3.69

 -15 -10 -5 0 5 10 15 20 25 30 35 40 45

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

Num ber o f measure ments

V-mean: 13.70 ?V-mean 0.16 Sigma: 4.98

 - 20 -15 -10 -5 0 5 10 15 20 25

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

N umber of measurements

U-mean: 0.06 ?U-mean 0.13 Sigma: 3.63

 -15 -10 - 5 0 5 10 15 20 25 30 35 40

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

N umber of measurements

V-mean: 13.28 ?V-mean 0.18 Sigma: 4.86
Figure VII.33.a.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Aeroglaze, Focal 

distance = 120 inches.

VII.298

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 20 -15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Numb er of m easureme nts

U-mean: -0.75 ?U-mean 0.11 Sigma: 3.23

 -15 -10 -5 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

Numb er of m easureme nts

V-mean: 5.72 ?V-mean 0.13 Sigma: 3.75

 - 20 -15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Num ber o f measure ments

U-mean: -0.81 ?U-mean 0.11 Sigma: 3.33

 -15 -10 -5 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

Num ber o f measure ments

V-mean: 5.71 ?V-mean 0.12 Sigma: 3.74

 - 20 -15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

N umber of measurements

U-mean: -0.69 ?U-mean 0.14 Sigma: 3.07

 -15 -10 -5 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

N umber of measurements

V-mean: 5.64 ?V-mean 0.16 Sigma: 3.62
Figure VII.33.a.(2)(c) - Velocity histograms obtained at closest approach – Aeroglaze, Focal 

distance = 120 inches.

VII.299

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 40 -30 -20 -10 0 10 20 30 40

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Numb er of m easureme nts

U-mean: -2.37 ?U-mean 0.63 Sigma: 6.86

 -20 -15 -10 -5 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

Numb er of m easureme nts

V-mean: 5.45 ?V-mean 0.38 Sigma: 4.11

 - 40 -30 -20 -10 0 10 20 30 40

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: -3.51 ?U-mean 0.31 Sigma: 6.67

 -200 -150 -100 -50 0 50 10 0 150 200 250

V-component velocity, m/s

 0

 2

 4

 6

 8

Nu mber o f measurem ents

V-mean: 19.19 ?V-mean 1.69 Sigma: 36.72

 - 20 -15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

N umber of measurements

U-mean: -1.18 ?U-mean 0.57 Sigma: 3.04

 -15 -10 -5 0 5 10 15 20 25

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

N umber of measurements

V-mean: 5.29 ?V-mean 0.60 Sigma: 3.22
Figure VII.33.b.(1) - Velocity statistics as each surface is moved toward the measurement volume – 

Aeroglaze, Focal distance = 180 inches.

VII.300

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Aeroglaze

Focal Distance = 180 inches

July 26, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Aeroglaze

Focal Distance = 180 inches

July 26, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Aeroglaze

Focal Distance = 180 inches

July 26, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Aeroglaze

Focal Distance = 180 inches

July 26, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Aeroglaze

Focal Distance = 180 inches

July 26, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.33.b.(2)(a) - Velocity histograms obtained at 36-inch separation – Aeroglaze, Focal 

distance = 180 inches.

VII.301

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Numb er of m easureme nts

U-mean: -0.04 ?U-mean 0.03 Sigma: 1.02

 4 6 8 10 12 14 16 18 20 2 2

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

V-mean: 11.74 ?V-mean 0.05 Sigma: 1.68

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Num ber o f measure ments

U-mean: -0.04 ?U-mean 0.03 Sigma: 1.06

 4 6 8 10 12 14 16 18 20 2 2

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

V-mean: 11.74 ?V-mean 0.05 Sigma: 1.68

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

N umber of measurements

U-mean: -0.03 ?U-mean 0.04 Sigma: 1.01

 4 6 8 10 12 14 16 18 20 2 2

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

V-mean: 11.74 ?V-mean 0.06 Sigma: 1.63
Figure VII.33.b.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Aeroglaze, Focal 

distance = 180 inches.

VII.302

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

U-mean: -0.33 ?U-mean 0.05 Sigma: 1.46

 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 11.65 ?V-mean 0.09 Sigma: 2.73

 - 10 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: -0.37 ?U-mean 0.05 Sigma: 1.57

 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Num ber o f measure ments

V-mean: 11.66 ?V-mean 0.09 Sigma: 2.74

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

N umber of measurements

U-mean: -0.38 ?U-mean 0.06 Sigma: 1.47

 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

N umber of measurements

V-mean: 11.66 ?V-mean 0.12 Sigma: 2.66
Figure VII.33.b.(2)(c) - Velocity histograms obtained at closest approach – Aeroglaze, Focal 

distance = 180 inches.

VII.303

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 15 -10 -5 0 5 10 15

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

U-mean: -0.77 ?U-mean 0.09 Sigma: 1.94

 -10 -5 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Numb er of m easureme nts

V-mean: 9.53 ?V-mean 0.15 Sigma: 3.27

 - 20 -15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

U-mean: -1.40 ?U-mean 0.14 Sigma: 3.45

 -10 -5 0 5 10 15 20 25 30 3 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Num ber o f measure ments

V-mean: 9.53 ?V-mean 0.15 Sigma: 3.69

 - 10 -8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

N umber of measurements

U-mean: -0.74 ?U-mean 0.13 Sigma: 1.81

 -10 -5 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

N umber of measurements

V-mean: 9.59 ?V-mean 0.24 Sigma: 3.18
Figure VII.33.c.(1) - Velocity statistics as each surface is moved toward the measurement volume – 

Aeroglaze, Focal distance = 228 inches.

VII.304

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Aeroglaze

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Aeroglaze

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Aeroglaze

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Aeroglaze

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Aeroglaze

Focal Distance = 228 inches

July 28, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.33.c.(2)(a) - Velocity histograms obtained at 36-inch separation – Aeroglaze, Focal 

distance = 228 inches.

VII.305

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Numb er of m easureme nts

U-mean: -0.17 ?U-mean 0.04 Sigma: 1.00

 2 4 6 8 10 12 14 16 18 20

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

V-mean: 8.70 ?V-mean 0.06 Sigma: 1.76

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Num ber o f measure ments

U-mean: -0.20 ?U-mean 0.04 Sigma: 1.15

 2 4 6 8 10 12 14 16 18 20

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

V-mean: 8.67 ?V-mean 0.06 Sigma: 1.79

 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

 55

N umber of mea suremen ts

U-mean: -0.17 ?U-mean 0.06 Sigma: 0.94

 2 4 6 8 10 12 14 16 18 20

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

V-mean: 8.81 ?V-mean 0.11 Sigma: 1.77
Figure VII.33.c.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Aeroglaze, Focal 

distance = 228 inches.

VII.306

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Numb er of m easureme nts

U-mean: -0.19 ?U-mean 0.09 Sigma: 1.22

 0 2 4 6 8 10 12 14 16 18 2 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

V-mean: 8.22 ?V-mean 0.13 Sigma: 1.82

 -120 -100 -80 -60 -40 -20 0 20 40 60 80 100

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Nu mber o f measurem ents

U-mean: -15.50 ?U-mean 0.94 Sigma: 21.21

 -30 -20 -1 0 0 10 20 30 4 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Num ber o f measure ments

V-mean: 7.89 ?V-mean 0.26 Sigma: 5.86

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

N umber of measurements

U-mean: -0.10 ?U-mean 0.19 Sigma: 1.01

 0 2 4 6 8 10 12 14 16 18 2 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

V-mean: 8.46 ?V-mean 0.33 Sigma: 1.78
Figure VII.33.c.(2)(c) - Velocity histograms obtained at closest approach – Aeroglaze, Focal 

distance = 228 inches.

VII.307

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Numb er of m easurem ents

U-mean: -0.21 ?U-mean 0.07 Sigma: 1.27

 0 2 4 6 8 10 12 14 16 18 2 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Numb er of m easurem ents

V-mean: 8.72 ?V-mean 0.11 Sigma: 1.84

 - 80 -60 -40 - 20 0 20 40 60

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

U-mean: -6.35 ?U-mean 0.46 Sigma: 11.32

 -10 -5 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

V-mean: 8.16 ?V-mean 0.12 Sigma: 2.89
Figure VII.33.d.(1) - Velocity statistics as each surface is moved toward the measurement volume – 

Aeroglaze, Focal distance = 276 inches.

VII.308

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Aeroglaze

Focal Distance = 276 inches

August 1, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Aeroglaze

Focal Distance = 276 inches

August 1, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Aeroglaze

Focal Distance = 276 inches

August 1, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Aeroglaze

Focal Distance = 276 inches

August 1, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Aeroglaze

Focal Distance = 276 inches

August 1, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.33.d.(2)(a) - Velocity histograms obtained at 36-inch separation – Aeroglaze, Focal 

distance = 276 inches.

VII.309

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Numb er of m easureme nts

U-mean: -0.06 ?U-mean 0.07 Sigma: 1.17

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 5.01 ?V-mean 0.15 Sigma: 2.45

 - 50 -40 -30 -20 -10 0 10 20 30 40

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: -3.91 ?U-mean 0.35 Sigma: 7.87

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 5.52 ?V-mean 0.12 Sigma: 2.63

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

 55

N umber of measurements

U-mean: 0.07 ?U-mean 0.21 Sigma: 1.02

 -10 -5 0 5 10 15 2 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

N umber of measurements

V-mean: 3.99 ?V-mean 0.46 Sigma: 2.27
Figure VII.33.d.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Aeroglaze, Focal 

distance = 276 inches.

VII.310

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Numb er of m easurem ents

U-mean: -0.11 ?U-mean 0.08 Sigma: 1.27

 -15 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

Numb er of measurem ents

V-mean: 4.76 ?V-mean 0.16 Sigma: 2.57

 -120 -100 -80 -60 -40 -20 0 20 40 60 80 100

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

N umber of measurements

U-mean: -14.26 ?U-mean 0.76 Sigma: 20.43

 -15 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

N umber of measurements

V-mean: 5.36 ?V-mean 0.11 Sigma: 3.04
Figure VII.33.d.(2)(c) - Velocity histograms obtained at closest approach – Aeroglaze, Focal 

distance = 276 inches.

VII.311

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 20 -15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Numb er of m easureme nts

U-mean: -0.97 ?U-mean 0.32 Sigma: 3.20

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

Numb er of m easureme nts

V-mean: 5.10 ?V-mean 0.27 Sigma: 2.63

 -150 -100 -50 0 50 100

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Nu mber o f measurem ents

U-mean: -21.07 ?U-mean 1.14 Sigma: 23.92

 -15 -10 -5 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 5.41 ?V-mean 0.16 Sigma: 3.44

 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 10

 20

 30

 40

 50

 60

 70

N umber of mea suremen ts

U-mean: -0.04 ?U-mean 0.32 Sigma: 0.69

 -10 -5 0 5 10 1 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

N umber of measurements

V-mean: 3.07 ?V-mean 0.95 Sigma: 2.06
Figure VII.34.a.- Velocity statistics as each surface is moved toward the measurement volume – Chem 

Glaze sample, Focal distance = 120 inches.

VII.312

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

ChemGlaze

Focal Distance = 120 inches

July 25, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

ChemGlaze

Focal Distance = 120 inches

July 25, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

ChemGlaze

Focal Distance = 120 inches

July 25, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

ChemGlaze

Focal Distance = 120 inches

July 25, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

ChemGlaze

Focal Distance = 120 inches

July 25, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.34.b.- Velocity statistics as each surface is moved toward the measurement volume – Chem 

Glaze sample, Focal distance = 180 inches.

VII.313

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

ChemGlaze

Focal Distance = 180 inches

July 27, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

ChemGlaze

Focal Distance = 180 inches

July 27, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

ChemGlaze

Focal Distance = 180 inches

July 27, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

ChemGlaze

Focal Distance = 180 inches

July 27, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

ChemGlaze

Focal Distance = 180 inches

July 27, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.34.c.- Velocity statistics as each surface is moved toward the measurement volume – Chem 

Glaze sample, Focal distance = 228 inches.

VII.314

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

ChemGlaze

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

ChemGlaze

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

ChemGlaze

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

ChemGlaze

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

ChemGlaze

Focal Distance = 228 inches

July 28, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.34.d.- Velocity statistics as each surface is moved toward the measurement volume – Chem 

Glaze sample, Focal distance = 276 inches.

VII.315

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

ChemGlaze

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

ChemGlaze

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

ChemGlaze

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

ChemGlaze

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

ChemGlaze

Focal Distance = 276 inches

August 2, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.35.a.(1) - Velocity statistics as each surface is moved toward the measurement volume – Semi 

gloss black paint with Rhodamine B added, Focal distance = 120 inches.

VII.316

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Rhodamine B

Focal Distance = 120 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Rhodamine B

Focal Distance = 120 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Rhodamine B

Focal Distance = 120 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Rhodamine B

Focal Distance = 120 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Rhodamine B

Focal Distance = 120 inches

August 4, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.35.a.(2)(a) - Velocity histograms obtained at 36-inch separation – Semi gloss black paint with 

Rhodamine B added, Focal distance = 120 inches.

VII.317

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

U-mean: -0.39 ?U-mean 0.05 Sigma: 1.49

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 10 15 20 25 30 3 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

Numb er of m easureme nts

V-mean: 20.89 ?V-mean 0.07 Sigma: 2.18

 - 10 -8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: -0.40 ?U-mean 0.05 Sigma: 1.63

 10 15 20 25 30 3 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

Num ber o f measure ments

V-mean: 20.82 ?V-mean 0.07 Sigma: 2.24

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

U-mean: -0.41 ?U-mean 0.07 Sigma: 1.48

 10 15 20 25 30 3 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

N umber of measurements

V-mean: 21.07 ?V-mean 0.10 Sigma: 2.22
Figure VII.35.a.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Semi gloss black 

paint with Rhodamine B added, Focal distance = 120 inches.

VII.318

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 10 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

U-mean: -0.50 ?U-mean 0.06 Sigma: 1.61

 10 15 20 25 30 3 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

V-mean: 22.12 ?V-mean 0.08 Sigma: 2.13

 - 10 -8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: -0.61 ?U-mean 0.06 Sigma: 1.87

 14 16 18 20 22 24 26 28 30 32 3 4

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 22.09 ?V-mean 0.07 Sigma: 2.12

 - 10 -8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

U-mean: -0.45 ?U-mean 0.11 Sigma: 1.69

 10 15 20 25 30 3 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

N umber of measurements

V-mean: 22.12 ?V-mean 0.14 Sigma: 2.15
Figure VII.35.a.(2)(c) - Velocity histograms obtained at closest approach – Semi gloss black paint with 

Rhodamine B added, Focal distance = 120 inches.

VII.319

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 10 - 8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

U-mean: -0.58 ?U-mean 0.07 Sigma: 1.67

 14 16 18 20 22 24 26 28 30 32 34

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 22.27 ?V-mean 0.08 Sigma: 2.07

 - 15 -10 -5 0 5 10 15

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: -0.70 ?U-mean 0.07 Sigma: 2.00

 14 16 18 20 22 24 26 28 30 32 34

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Num ber o f measure ments

V-mean: 22.22 ?V-mean 0.07 Sigma: 2.07

 - 10 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

U-mean: -0.65 ?U-mean 0.12 Sigma: 1.52

 10 15 20 25 30 35

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

N umber of measurements

V-mean: 22.37 ?V-mean 0.17 Sigma: 2.14
Figure VII.35.b.(1) - Velocity statistics as each surface is moved toward the measurement volume – Semi 

gloss black paint with Rhodamine B added, Focal distance = 180 inches.

VII.320

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Rhodamine B

Focal Distance = 180 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Rhodamine B

Focal Distance = 180 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Rhodamine B

Focal Distance = 180 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Rhodamine B

Focal Distance = 180 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Rhodamine B

Focal Distance = 180 inches

August 4, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.35.b.(2)(a) - Velocity histograms obtained at 36-inch separation – Semi gloss black paint with 

Rhodamine B added, Focal distance = 180 inches.

VII.321

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 10 -8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

U-mean: -0.53 ?U-mean 0.06 Sigma: 1.84

 0 5 1 0 15 20 25 30 3 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 11.07 ?V-mean 0.10 Sigma: 3.11

 - 10 -8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

U-mean: -0.57 ?U-mean 0.06 Sigma: 1.95

 0 5 1 0 15 20 25 30 3 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Num ber o f measure ments

V-mean: 11.07 ?V-mean 0.10 Sigma: 3.13

 - 10 -8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

N umber of measurements

U-mean: -0.48 ?U-mean 0.10 Sigma: 1.80

 -10 -5 0 5 10 15 20 25 30 3 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

N umber of measurements

V-mean: 10.87 ?V-mean 0.17 Sigma: 3.15
Figure VII.35.b.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Semi gloss black 

paint with Rhodamine B added, Focal distance = 180 inches.

VII.322

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 15 -10 -5 0 5 10 15

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

U-mean: -0.66 ?U-mean 0.09 Sigma: 2.16

 0 5 10 15 20 25 30 35

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 11.13 ?V-mean 0.13 Sigma: 3.11

 - 20 -15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

U-mean: -0.97 ?U-mean 0.11 Sigma: 2.78

 -10 -5 0 5 10 15 20 25 30 35

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Num ber o f measure ments

V-mean: 11.10 ?V-mean 0.12 Sigma: 3.16

 - 10 - 8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

N umber of measurements

U-mean: -0.50 ?U-mean 0.19 Sigma: 1.90

 0 5 10 15 20 25 30 35

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

N umber of measurements

V-mean: 11.12 ?V-mean 0.30 Sigma: 3.01
Figure VII.35.b.(2)(c) - Velocity histograms obtained at closest approach – Semi gloss black paint with 

Rhodamine B added, Focal distance = 180 inches.

VII.323

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 10 - 8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

U-mean: -0.56 ?U-mean 0.11 Sigma: 1.93

 -10 -5 0 5 10 15 20 25 30 35

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

Numb er of m easureme nts

V-mean: 10.79 ?V-mean 0.19 Sigma: 3.30

 - 20 -15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

U-mean: -0.75 ?U-mean 0.13 Sigma: 2.44

 -10 -5 0 5 10 15 20 25 30 35

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

Num ber o f measure ments

V-mean: 10.81 ?V-mean 0.17 Sigma: 3.30

 - 15 -10 -5 0 5 10 15

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

N umber of measurements

U-mean: -0.63 ?U-mean 0.23 Sigma: 1.97

 -10 -5 0 5 10 15 20 25 30 35

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

N umber of measurements

V-mean: 10.70 ?V-mean 0.38 Sigma: 3.19
Figure VII.35.c.(1) - Velocity statistics as each surface is moved toward the measurement volume – Semi 

gloss black paint with Rhodamine B added, Focal distance = 228 inches.

VII.324

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Rhodamine B

Focal Distance = 228 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Rhodamine B

Focal Distance = 228 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Rhodamine B

Focal Distance = 228 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Rhodamine B

Focal Distance = 228 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Rhodamine B

Focal Distance = 228 inches

August 4, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.35.c.(2)(a) - Velocity histograms obtained at 36-inch separation – Semi gloss black paint with 

Rhodamine B added, Focal distance = 228 inches.

VII.325

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

N umber of me asu reme nts

U-mean: -0.25 ?U-mean 0.03 Sigma: 1.00

 2 4 6 8 10 12 14 16 18 20 2 2

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Numb er of m easureme nts

V-mean: 9.74 ?V-mean 0.06 Sigma: 1.98

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Num ber o f measure ments

U-mean: -0.25 ?U-mean 0.03 Sigma: 1.03

 2 4 6 8 10 12 14 16 18 20 2 2

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Num ber o f measure ments

V-mean: 9.72 ?V-mean 0.06 Sigma: 2.00

 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

N umber of mea suremen ts

U-mean: -0.25 ?U-mean 0.04 Sigma: 0.99

 2 4 6 8 10 12 14 16 18 20 2 2

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

N umber of measurements

V-mean: 9.85 ?V-mean 0.07 Sigma: 1.83
Figure VII.35.c.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Semi gloss black 

paint with Rhodamine B added, Focal distance = 228 inches.

VII.326

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -8 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

N umber of me asu reme nts

U-mean: -0.26 ?U-mean 0.04 Sigma: 1.11

 2 4 6 8 10 12 14 16 18 20 2 2

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Numb er of m easureme nts

V-mean: 9.82 ?V-mean 0.07 Sigma: 2.03

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

Num ber o f measure ments

U-mean: -0.30 ?U-mean 0.04 Sigma: 1.26

 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Num ber o f measure ments

V-mean: 9.79 ?V-mean 0.07 Sigma: 2.07

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

N umber of measurements

U-mean: -0.25 ?U-mean 0.05 Sigma: 1.03

 2 4 6 8 10 12 14 16 18 20 2 2

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

N umber of measurements

V-mean: 9.95 ?V-mean 0.09 Sigma: 1.86
Figure VII.35.c.(2)(c) - Velocity histograms obtained at closest approach – Semi gloss black paint with 

Rhodamine B added, Focal distance = 228 inches.

VII.327

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Numb er of m easureme nts

U-mean: -0.38 ?U-mean 0.04 Sigma: 1.25

 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

V-mean: 9.28 ?V-mean 0.09 Sigma: 2.44

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Num ber o f measure ments

U-mean: -0.46 ?U-mean 0.05 Sigma: 1.46

 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 9.26 ?V-mean 0.09 Sigma: 2.50

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

N umber of measurements

U-mean: -0.39 ?U-mean 0.06 Sigma: 1.22

 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

V-mean: 9.42 ?V-mean 0.12 Sigma: 2.27
Figure VII.35.d.(1) - Velocity statistics as each surface is moved toward the measurement volume – Semi 

gloss black paint with Rhodamine B added, Focal distance = 276 inches.

VII.328

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Rhodamine B

Focal Distance = 276 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Rhodamine B

Focal Distance = 276 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Rhodamine B

Focal Distance = 276 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Rhodamine B

Focal Distance = 276 inches

August 4, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Rhodamine B

Focal Distance = 276 inches

August 4, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.35.d.(2)(a) - Velocity histograms obtained at 36-inch separation – Semi gloss black paint with 

Rhodamine B added, Focal distance = 276 inches.

VII.329

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

Numb er of m easurem ents

U-mean: -0.14 ?U-mean 0.05 Sigma: 1.09

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

V-mean: 5.86 ?V-mean 0.11 Sigma: 2.58

 - 10 -8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

Num ber o f measure ments

U-mean: -0.27 ?U-mean 0.06 Sigma: 1.64

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 5.94 ?V-mean 0.10 Sigma: 2.65

 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

N umber of measurements

U-mean: -0.10 ?U-mean 0.09 Sigma: 1.05

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

N umber of measurements

V-mean: 5.32 ?V-mean 0.22 Sigma: 2.47
Figure VII.35.d.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Semi gloss black 

paint with Rhodamine B added, Focal distance = 276 inches.

VII.330

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

Numb er of m easurem ents

U-mean: -0.28 ?U-mean 0.07 Sigma: 1.40

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 5.65 ?V-mean 0.13 Sigma: 2.60

 - 60 -50 -40 -30 -20 -10 0 10 20 30 40 50

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

U-mean: -6.15 ?U-mean 0.35 Sigma: 10.53

 -15 -10 -5 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Num ber o f measure ments

V-mean: 5.75 ?V-mean 0.10 Sigma: 3.14

 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

N umber of mea suremen ts

U-mean: -0.12 ?U-mean 0.14 Sigma: 0.99

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

N umber of measurements

V-mean: 5.11 ?V-mean 0.36 Sigma: 2.53
Figure VII.35.d.(2)(c) - Velocity histograms obtained at closest approach – Semi gloss black paint with 

Rhodamine B added, Focal distance = 276 inches.

VII.331

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 10 -8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

Numb er of m easureme nts

U-mean: -0.37 ?U-mean 0.14 Sigma: 1.90

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 5.58 ?V-mean 0.19 Sigma: 2.61

 -150 -100 -50 0 50 100

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Nu mber o f measurem ents

U-mean: -18.67 ?U-mean 0.81 Sigma: 22.69

 -20 -15 -10 -5 0 5 10 15 20 25 30 3 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Num ber o f measure ments

V-mean: 6.42 ?V-mean 0.15 Sigma: 4.32

 -8 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

N umber of mea suremen ts

U-mean: -0.09 ?U-mean 0.27 Sigma: 1.11

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

N umber of measurements

V-mean: 4.94 ?V-mean 0.59 Sigma: 2.45
Figure VII.36.- Signal-to-noise statistics as each surface is moved toward the measurement volume – 

Semi gloss black paint with Rhodamine B added, Focal distance = 120 inches. Comparison to determine 

effects of Rhodamine B aging.

Figure VII.37.- Signal-to-noise statistics as each surface is moved toward the measurement volume – 

Semi gloss black paint with Rhodamine B added, Focal distance = 120 and 180 inches. Comparison to 

determine effects of Rhodamine B aging – short interval.

VII.332

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

FD = 120 inches

 6/20/11

 6/30/11

 7/14/11

 8/4/11

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Error bars = Standard Deviation

Threshold

0.1 1 10

0

5

10

15

20

25

30

35

40

FD = 120 inches

Threshold Error bars = Standard Deviation

V-component (514.5 nm)

 6/20/11

 6/30/11

 7/14/11

 8/4/11

Signal-to-noise ratio

Distance of measurement volume to surface, inch

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

10 deg tilt

 FD = 120 inches 8/4/11

 FD = 120 inches 8/8/11

 FD = 180 inches 8/4/11

 FD = 180 inches 8/8/11

 FD = 180 inches 8/11/11

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Error bars = Standard Deviation

Threshold

10 deg tilt

5 deg tilt

0.1 1 10

0

5

10

15

20

25

30

35

40

10 deg tilt

Threshold Error bars = Standard Deviation

V-component (514.5 nm)

 FD = 120 inches 8/4/11

 FD = 120 inches 8/8/11

 FD = 180 inches 8/4/11

 FD = 180 inches 8/8/11

 FD = 180 inches 8/11/11

Signal-to-noise ratio

Distance of measurement volume to surface, inch

5 deg tilt

10 deg tilt
Figure VII.38.- Signal-to-noise statistics as each surface is moved toward the measurement volume – 

Semi gloss black paint with Rhodamine B added, Focal distance = 228 and 276 inches. Comparison to 

determine effects of Rhodamine B aging – short interval.

VII.333

0.1 1 10

0

2

4

6

8

10

12

14

16

18

20

15 deg tilt

20 deg tilt

12 deg tilt

15 deg tilt

30 deg tilt

 FD = 228 inches 8/4/11

 FD = 228 inches 8/11/11

 FD = 276 inches 8/4/11

 FD = 276 inches 8/11/11

Signal-to-noise ratio

Distance of measurement volume to surface, inch

U-component (488.0 nm)

Error bars = Standard Deviation

Threshold

10 deg tilt

25 deg tilt

0.1 1 10

0

5

10

15

20

25

30

35

40

30 deg tilt

15 deg tilt

12 deg tilt

10 deg tilt

20 deg tilt

Threshold Error bars = Standard Deviation

V-component (514.5 nm)

 FD = 228 inches 8/4/11

 FD = 228 inches 8/11/11

 FD = 276 inches 8/4/11

 FD = 276 inches 8/11/11

Signal-to-noise ratio

Distance of measurement volume to surface, inch

25 deg tilt

15 deg tilt
Figure VII.39.a.(1)- Velocity statistics as each surface is moved toward the measurement volume – 

Nanotube matrix sample, Focal distance = 120 inches.

VII.334

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Nanotube

Focal Distance = 120 inches

July 14, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Nanotube

Focal Distance = 120 inches

July 14, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Nanotube

Focal Distance = 120 inches

July 14, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Nanotube

Focal Distance = 120 inches

July 14, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Nanotube

Focal Distance = 120 inches

July 14, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.39.a.(2)(a) - Velocity histograms obtained at 36-inch separation – Nanotube matrix sample, 

Focal distance = 120 inches.

VII.335

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 14 16 18 20 22 24 26 28 30 32 34

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

V-mean: 21.47 ?V-mean 0.06 Sigma: 1.88

 -4 -2 0 2 4 6 8 10 12 14

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

U-mean: 3.32 ?U-mean 0.05 Sigma: 1.44

 -6 -4 -2 0 2 4 6 8 10 12 14

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: 3.30 ?U-mean 0.05 Sigma: 1.51

 14 16 18 20 22 24 26 28 30 32 34

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 21.46 ?V-mean 0.06 Sigma: 1.89

 -4 -2 0 2 4 6 8 10 12 14

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

U-mean: 3.29 ?U-mean 0.06 Sigma: 1.42

 14 16 18 20 22 24 26 28 30 32

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

V-mean: 21.56 ?V-mean 0.08 Sigma: 1.81
Figure VII.39.a.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Nanotube matrix 

sample, Focal distance = 120 inches.

VII.336

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 20 -15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Numb er of m easureme nts

U-mean: 0.01 ?U-mean 0.10 Sigma: 3.11

 -10 -5 0 5 10 15 20 25 30 35 4 0

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

Numb er of m easureme nts

V-mean: 14.28 ?V-mean 0.15 Sigma: 4.71

 - 20 -15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Num ber o f measure ments

U-mean: -0.01 ?U-mean 0.10 Sigma: 3.16

 -10 -5 0 5 10 15 20 25 30 35 4 0

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

Num ber o f measure ments

V-mean: 14.27 ?V-mean 0.15 Sigma: 4.70

 - 20 -15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

N umber of measurements

U-mean: -0.04 ?U-mean 0.12 Sigma: 3.09

 -10 -5 0 5 10 15 20 25 30 35 40 4 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

N umber of measurements

V-mean: 14.50 ?V-mean 0.19 Sigma: 4.70
Figure VII.39.a.(2)(c) - Velocity histograms obtained at closest approach – Nanotube matrix sample, Focal 

distance = 120 inches.

VII.337

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 20 -15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

U-mean: -0.75 ?U-mean 0.14 Sigma: 2.84

 0 5 10 15 20 25 30 35 40

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Numb er of m easureme nts

V-mean: 18.38 ?V-mean 0.18 Sigma: 3.63

 -120 -100 -80 -60 -40 -20 0 20 40 60 80 100

U-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

Nu mber o f measurem ents

U-mean: -11.79 ?U-mean 0.70 Sigma: 19.63

 0 5 10 15 20 25 30 35 40

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Num ber o f measure ments

V-mean: 18.18 ?V-mean 0.13 Sigma: 3.74

 - 15 -10 -5 0 5 10 15

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

N umber of measurements

U-mean: -0.47 ?U-mean 0.28 Sigma: 2.36

 5 10 15 20 25 30 35 40

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

N umber of measurements

V-mean: 18.39 ?V-mean 0.40 Sigma: 3.32
Figure VII.39.b.(1) - Velocity statistics as each surface is moved toward the measurement volume – 

Nanotube matrix sample, Focal distance = 180 inches.

VII.338

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Nanotube

Focal Distance = 180 inches

July 27, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Nanotube

Focal Distance = 180 inches

July 27, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Nanotube

Focal Distance = 180 inches

July 27, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Nanotube

Focal Distance = 180 inches

July 27, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Nanotube

Focal Distance = 180 inches

July 27, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.39.b.(2)(a) - Velocity histograms obtained at 36-inch separation – Nanotube matrix sample, 

Focal distance = 180 inches.

VII.339

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Numb er of m easureme nts

U-mean: -0.23 ?U-mean 0.04 Sigma: 1.27

 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

V-mean: 11.84 ?V-mean 0.08 Sigma: 2.42

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

Num ber o f measure ments

U-mean: -0.25 ?U-mean 0.04 Sigma: 1.32

 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 11.84 ?V-mean 0.08 Sigma: 2.42

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

N umber of measurements

U-mean: -0.22 ?U-mean 0.05 Sigma: 1.25

 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

N umber of measurements

V-mean: 11.86 ?V-mean 0.09 Sigma: 2.40
Figure VII.39.b.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Nanotube matrix 

sample, Focal distance = 180 inches.

VII.340

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

U-mean: -0.38 ?U-mean 0.05 Sigma: 1.44

 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 11.42 ?V-mean 0.09 Sigma: 2.72

 - 10 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: -0.41 ?U-mean 0.05 Sigma: 1.53

 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Num ber o f measure ments

V-mean: 11.42 ?V-mean 0.09 Sigma: 2.74

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

U-mean: -0.39 ?U-mean 0.06 Sigma: 1.40

 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

N umber of measurements

V-mean: 11.51 ?V-mean 0.12 Sigma: 2.58
Figure VII.39.b.(2)(c) - Velocity histograms obtained at closest approach – Nanotube matrix sample, Focal 

distance = 180 inches.

VII.341

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 10 -8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

U-mean: -0.62 ?U-mean 0.07 Sigma: 1.85

 -10 -5 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Numb er of m easureme nts

V-mean: 9.71 ?V-mean 0.12 Sigma: 3.12

 - 15 -10 -5 0 5 10 15 20

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

U-mean: -0.82 ?U-mean 0.08 Sigma: 2.41

 -10 -5 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Num ber o f measure ments

V-mean: 9.69 ?V-mean 0.11 Sigma: 3.30

 - 10 -8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

N umber of measurements

U-mean: -0.64 ?U-mean 0.11 Sigma: 1.68

 -10 -5 0 5 10 15 20 25 3 0

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

N umber of measurements

V-mean: 9.76 ?V-mean 0.20 Sigma: 3.04
Figure VII.39.c.(1) - Velocity statistics as each surface is moved toward the measurement volume – 

Nanotube matrix sample, Focal distance = 228 inches.

VII.342

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Nanotube

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Nanotube

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Nanotube

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Nanotube

Focal Distance = 228 inches

July 28, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Nanotube

Focal Distance = 228 inches

July 28, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.39.c.(2)(a) - Velocity histograms obtained at 36-inch separation – Nanotube matrix sample, 

Focal distance = 228 inches.

VII.343

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 10 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

U-mean: -0.43 ?U-mean 0.06 Sigma: 1.55

 -15 -10 -5 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

Numb er of m easureme nts

V-mean: 7.44 ?V-mean 0.12 Sigma: 3.28

 - 10 - 8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: -0.48 ?U-mean 0.06 Sigma: 1.72

 -10 -5 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Num ber o f measure ments

V-mean: 7.55 ?V-mean 0.11 Sigma: 3.24

 - 10 - 8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

U-mean: -0.44 ?U-mean 0.10 Sigma: 1.63

 -15 -10 -5 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

N umber of measurements

V-mean: 6.92 ?V-mean 0.21 Sigma: 3.32
Figure VII.39.c.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Nanotube matrix 

sample, Focal distance = 228 inches.

VII.344

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 - 10 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Numb er of m easureme nts

U-mean: -0.41 ?U-mean 0.07 Sigma: 1.60

 -15 -10 -5 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

Numb er of m easureme nts

V-mean: 7.36 ?V-mean 0.14 Sigma: 3.26

 - 10 - 8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: -0.52 ?U-mean 0.08 Sigma: 1.95

 -15 -10 -5 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

 20

Num ber o f measure ments

V-mean: 7.42 ?V-mean 0.13 Sigma: 3.28

 - 10 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

U-mean: -0.50 ?U-mean 0.15 Sigma: 1.55

 -15 -10 -5 0 5 10 15 20 25 30

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

N umber of measurements

V-mean: 6.80 ?V-mean 0.32 Sigma: 3.27
Figure VII.39.c.(2)(c) - Velocity histograms obtained at closest approach – Nanotube matrix sample, Focal 

distance = 228 inches.

VII.345

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

 55

Numb er of measurem ents

U-mean: -0.14 ?U-mean 0.08 Sigma: 1.22

 0 2 4 6 8 10 12 14 16 18 20

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Numb er of m easureme nts

V-mean: 7.79 ?V-mean 0.12 Sigma: 1.76

 - 10 - 8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Num ber o f measure ments

U-mean: -0.37 ?U-mean 0.12 Sigma: 1.89

 0 2 4 6 8 10 12 14 16 18 20

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 7.62 ?V-mean 0.12 Sigma: 1.99

 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

 55

N umber of mea suremen ts

U-mean: -0.17 ?U-mean 0.12 Sigma: 0.80

 0 2 4 6 8 10 12 14 16 18

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

V-mean: 7.92 ?V-mean 0.26 Sigma: 1.72
Figure VII.39.d.(1) - Velocity statistics as each surface is moved toward the measurement volume – 

Nanotube matrix sample, Focal distance = 276 inches.

VII.346

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Nanotube

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Nanotube

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Nanotube

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Nanotube

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Nanotube

Focal Distance = 276 inches

August 2, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
Figure VII.39.d.(2)(a) - Velocity histograms obtained at 36-inch separation – Nanotube matrix sample, 

Focal distance = 276 inches.

VII.347

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Numb er of m easureme nts

U-mean: -0.08 ?U-mean 0.06 Sigma: 1.17

 -10 -5 0 5 10 15 20 25

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 5.37 ?V-mean 0.12 Sigma: 2.45

 - 10 - 8 -6 -4 -2 0 2 4 6 8 10 12

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Num ber o f measure ments

U-mean: -0.31 ?U-mean 0.08 Sigma: 1.86

 -10 -5 0 5 10 15 20 25

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 5.63 ?V-mean 0.11 Sigma: 2.50

 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

 55

N umber of mea suremen ts

U-mean: 0.00 ?U-mean 0.10 Sigma: 0.92

 -10 -5 0 5 10 15 20 25

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

N umber of measurements

V-mean: 4.54 ?V-mean 0.27 Sigma: 2.43
Figure VII.39.d.(2)(b) - Velocity histograms obtained at first velocity/sigma deviation – Nanotube matrix 

sample, Focal distance = 276 inches.

VII.348

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Numb er of m easurem ents

U-mean: -0.07 ?U-mean 0.06 Sigma: 1.20

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of measurem ents

V-mean: 5.34 ?V-mean 0.13 Sigma: 2.49

 - 80 -60 -40 - 20 0 20 40 60

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

N umber of measurements

U-mean: -6.48 ?U-mean 0.40 Sigma: 11.04

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

N umber of measurements

V-mean: 5.83 ?V-mean 0.10 Sigma: 2.68
Figure VII.39.d.(2)(c) - Velocity histograms obtained at closest approach – Nanotube matrix sample, Focal 

distance = 276 inches.

VII.349

(i) Signal-to-noise ratio threshold = 5 (7 dB) 

(ii) Signal-to-noise ratio threshold = 2.5 (5 dB)

(iii) Signal-to-noise ratio threshold = 10 (10 dB)

 -8 -6 -4 -2 0 2 4 6 8 10

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

Numb er of m easureme nts

U-mean: -0.08 ?U-mean 0.06 Sigma: 1.15

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

Numb er of m easureme nts

V-mean: 5.42 ?V-mean 0.13 Sigma: 2.47

 - 60 -50 -40 -30 -20 -10 0 10 20 30 40 50

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

Num ber o f measure ments

U-mean: -5.91 ?U-mean 0.39 Sigma: 10.56

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

Num ber o f measure ments

V-mean: 5.80 ?V-mean 0.10 Sigma: 2.73

 -6 -4 -2 0 2 4 6 8

U-component velocity, m/s

 0

 5

 10

 15

 20

 25

 30

 35

 40

 45

 50

N umber of mea suremen ts

U-mean: 0.04 ?U-mean 0.13 Sigma: 0.90

 -10 -5 0 5 10 15 20 2 5

V-component velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

 18

N umber of measurements

V-mean: 4.55 ?V-mean 0.35 Sigma: 2.40
Figure VII.39.e.- Velocity statistics as each surface is moved toward the measurement volume – 

Nanotube matrix sample, Focal distance = 276 inches – damaged surface.

VII.350

0.1 1 10

0

500

1000

1500

2000

2500

3000

3500

4000

0

5

10

15

20

Nanotube - smeared

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Number of acceptable signal bursts

Distance of measurement volume to surface, inch

 Signal-to-noise ratio (U-component)

0.1 1 10

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Nanotube - smeared

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

5

10

15

20

25

Nanotube - smeared

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

V-component mean velocity, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

Nanotube - smeared

Focal Distance = 276 inches

August 2, 2011

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

U-component standard deviation, m/s

Distance of measurement volume to surface, inch

0.1 1 10

0

1

2

3

4

5

6

7

8

9

10

 SNR threshold = 5 (7 dB)

 SNR threshold = 2.5 (5 dB)

 SNR threshold = 10 (10 dB)

Nanotube - smeared

Focal Distance = 276 inches

August 2, 2011

V-component standard deviation, m/s

Distance of measurement volume to surface, inch
References

Adrian, R. J.; and Earley, W. L.: Evaluation of LDV Performance Using Mie Scattering 

Theory. Symposium on Laser Anemometry, University of Minnesota, October 22-24, 1975.

Albrecht, H. E.; Borys, M.; Damaschke, N.; and, Tropea, C.: Laser Doppler and Phase 

Doppler Measurement Techniques. Springer, Berlin, 2003.

Asher, J. A.: LDV Systems Development and Testing. The Use of the Laser Doppler 

Velocimeter for Flow Measurements, W. H. Stevenson andH. D. Thompson, eds., 

ContractN00014-67-A0226-055, Purdue Univ., pp. 338-347, Nov. 1972.

Baker, G. D.; Murphy, R. J.; and Meyers, J. F.: Database for LDV Signal Processor 

Performance Analysis. 13th International Congress on Instrumentation in Aerospace 

Simulation Facilities, Göttingen, West Germany, September 18-21, 1989. 

Brayton, D. B.: A Simple Laser, Doppler Shift, Velocity Meter with Self-Aligning Optics. 

Presented at the Electro-Optical Systems Design Conference, New York, NY, September 

16-18, 1969.

Brayton, D. B.; and Goethert, W. H.: A New Dual Scatter, Laser, Doppler Shift Velocity 

Measuring Technique. Instrumentation in the Aerospace Industry, Vol. 16, pp. 14-26, 1970.

Brayton, D. B.; Kalb, H. T.; and Crosswy, F. L.: A Two- Component, Dual-Scatter Laser 

Doppler Velocimeter with Frequency Burst Signal Readout. Presented at the Project Squid 

Workshop on The Use of the Laser Doppler Velocimeter for Flow Measurements, Purdue 

University, March 9-10, 1972.

Cavone, A. A.; Sterlina, P. S.; Clemmons, J. I., Jr.; and Meyers, J. F.: A High-Speed Buffer 

for LV Data Acquisition. Proceedings of the International Congress on Instrumentation in 

Aerospace Simulation Facilities, College of William and Mary, Williamsburg, VA, pp. 113-

119, June 22-25, 1987.

Clemmons, J. I., Jr.: Instrument for determining coincidence and elapse time between 

independent sources of random sequential events. United States Patent 4,392,749, July 12, 

1983.

Durst, F. and Whitelaw, J. H.: Optimization of optical anemometers. Proceedings of the 

Royal Society of London A, Vol. 324, pp. 157-181, 1971.

Dyott, R. B.: The fibre-optic Doppler anemometer. Microwaves, Optics and Acoustics, Vol. 

2(1), pp. 13-18, January 1978.

References.1
Edwards, R. V.; and Meyers, J. F.: An Overview of Particle Sampling Bias. Proceedings of 

the Second International Symposium on Applications of Laser Anemometry to Fluid 

Mechanics, Lisbon, Portugal, paper 2.1, July 2-4, 1984.

Report of the Special Panel on Statistical Particle Bias Problems in Laser Anemometry. R. 

V. Edwards, ed., Journal of Fluid Engineering, Vol. 109, pp. 89-93, June, 1987.

Elliott, J. W.; Althoff, S. L.; and Sailey, R. H.: Inflow Measurements Made With a Laser 

Velocimeter on a Helicopter Model in Forward Flight. Volume III Rectangular Planform 

Blades at an Advance Ratio of 0.30. NASA TM-100543, 1988.

Foreman, J. W., Jr.; George, E. W.; and Lewis, R. D.: Measurement of Localized Flow 

Velocities in Gases With a Laser Doppler Flowmeter. Applied Physics Letters, Vol. 7, No. 4, 

pp. 77-78, Aug. 15, 1965.

Fridman, J. D.; Kinnard, K. F.; and Meister, K.: Laser Doppler Instrumentation for the 

Measurement of Turbulence in Gas and Fluid Flows. Electro-Optical Systems Design 

Conference, New York, NY, September 16-18, 1969.

Gartrell, L. R. and Jordan, F. J.: Demonstration of a Rapid-ScanTwo-Dimensional Laser 

Velocimetry in the Langley Vortex Research Facility for Research in Aerial Application. 

NASA TM-74081, August, 1977.

Goldstein, R. J.; and Kreid, D. K.: Measurement of Laminar Flow Developed in a Square 

Duct Using a Laser Doppler Flowmeter. Journal of Applied Mechanics, Item 34, Series E, 

No. 4, pp. 813-818, December 1967.

Grant, G. R.; and Orloff, K. L.: Two-Color Dual-Beam Backscatter Laser Doppler 

Velocimeter. Applied Optics, Vol. 12, No. 12, pp. 2913-2916, December 1973.

Griskey, R. G.; Balmer, R. T.; and Brinkley, J. L.: An Automatic Scanning LDV System. 

Minnesota Symposium on Laser Anemometry - Proceedings, E. R. G. Eckert, ed., Univ. of

Minnesota, pp. 217-230, October 22-24, 1975.

Hart, R. C.; Balla, R. J.; Herring, G. C.; and Jenkins, L. N.: Seedless Laser Velocimetry 

Using Heterodyne Laser-induced Thermal Acoustics. Institute for Computer Applications 

in Science and Engineering, NASA/CR-2001-211021, 2001.

Hepner, T. E.: State-of-the-art laser Doppler velocimeter signal processors calibration and 

evaluation. 32nd Aerospace Sciences Meeting and Exhibit, Reno, NV, paper AIAA-1994-42, 

January 10-13, 1994.

Hoad, D. R.; Elliott, J. W.; and Althoff, S. L.: Rotor Inflow Variability with Advance Ratio. 

44th Annual Forum of the American Helicopter Society, Washington, DC, 1988.

References.2
Hoad, D. R.; Meyers, J. F.; Young, W. H., Jr.; and Hepner, T. E.: Laser Velocimeter Survey 

About a NACA 0012 Wing at Low Angles of Attack. TM-74040, January 1978.

Hoad, D. R.; Meyers, J. F.; Young, W. H., Jr.; and Hepner, T. E.: Correlation of Laser 

Velocimeter Measurements Over a Wing with Results of Two Prediction Techniques. TP1168, April 1978. 

Hoad, D. R.; Meyers, J. F.; and Young, W. H., Jr.: Velocity Measurements about a NACA 

00l2 Airfoil with Laser Velocimeter. Army Science Conference, West Point, NY, June 1978.

Hoad, D. R., Rhodes, D. B., and Meyers, J. F.: Preliminary Rotor Wake Measurements with 

a Laser Velocimeter. NASA TM 83246, 1983 .

Huffaker, R. M.; Fuller, C. E.; and Lawrence, T. R.: Application of Laser Doppler Velocity 

Instrumentation to the Measurement of Jet Turbulence. International Automotive 

Engineering Congress, Detroit, MI, January 13-17, 1969.

Huffaker, R. M.; Fuller, C. E.; and Lawrence, T. R.: Application of Laser Doppler Velocity 

Instrumentation to the Measurement of Jet Turbulence. Paper 690266, Soc. Automotive 

Engineers, January, 1969.

Huffaker, R.M.: Laser Doppler Detection Systems for Gas Velocity Measurement. Applied 

Optics, Vol. 9, No. 5, pp. 1026-1039, May 1970.

Iten, P. D.; and Mastner, J.: Laser Doppler Velocimeter Offering High Spatial and 

Temporal Resolution. Flow – Its Measurement and Control in Science and Industry, 

Volume One, Part Two, R. E. Wendt, Jr., ed., Instrument Soc. of America, pp. 1007-1013, 

1974.

Junge, C.: The Size Distribution and Aging of Natural Aerosols as Determined from 

Electrical and Optical Data on the Atmosphere. AMS Journal, Vol. 12, Iss. 1, February 

1955.

Knuhtsen, J.; Olldag, E.; and, Buchhave, P.: Fibre-optic laser Doppler anemometer with 

Bragg frequency shift utilising polarisation-preserving single-mode fibre. Journal of 

Physics E: Scientific Instruments, Vol. 15, pp. 1188-1191, 1982.

Lehmann, B.: Geschwindigkeitsmessung mit Laser-Doppler-Anemometer Verfahren. 

Wissenschaftliche Berichte AERG-Telefunken 41, 141-145, 1968. (in German)

Lennert, A. E.; Brayton, D. B.; Goethert, W. H.; and Smith, F. H.: Laser Applications for 

Flow Field Diagnostics. Laser J., vol. 2, no. 2, pp. 19-27, Mar/Apr. 1970.

References.3
Lennert, A. E.; Brayton, E. B.; Crosswy, F. L.; et al.: Summary Report of the Development 

of a Laser Velocimeter To Be Used in AEDC Wind Tunnels. AEDC-TR-70-101,U. S. Air 

Force, July 1970.

Lennert, A. E.; Smith, F. H., Jr.; and Kalb, H. T.: Application of Dual Scatter Laser 

Doppler Velocimeters for Wind Tunnel Measurements. 4th International Congress on 

Instrumentation in Aerospace Simulation Facilities, von Karman Institute for Fluid

Dynamics, June 21-23, 1971.

Mazumder, M. K.: Laser Doppler Velocity Measurement Without Directional Ambiguity by 

Using Frequency Shifted Incident Beams. Applied Physics Letters, Vol. 16(11), pp. 462-

464, June 1, 1970.

Mayo, W. T., Jr.: Modeling Laser Velocimeter Signals as Triply Stochastic Poisson 

Processes. Symposium on Laser Anemometry, University of Minnesota, October 22-24, 

1975.

Meyers, J. F.: Investigation and Calculations of Basic Parameters for the Application of the 

Laser Doppler Velocimeter. TN D-6125, April 1971. 

Meyers, J. F.: Applications of Laser Velocimetry to Large Scale and Specialized 

Aerodynamic Tests. TSI Quarterly, Vol. V, Issue 4, pp. 5- 12, November/December 1979. 

Meyers, J. F.: Analysis of the Dedicated Laser Velocimeter Systems at NASA - Langley 

Research Center. Proceedings of the Fourth International Symposium on Applications of 

Laser Anemometry to Fluid Mechanics, Lisbon, Portugal, paper 12.4, July 11-14, 1988.

Meyers, J. F.: Generation of Particles and Seeding. von Karman Institute for Fluid 

Dynamics, Lecture series 1991-08, Laser Velocimetry, Brussels, Belgium, June 10-14, 1991.

Meyers, J. F.: Biasing Errors and Corrections. Von Karman Institute for Fluid Dynamics, 

Lecture series 1991-08, Laser Velocimetry, Brussels, Belgium, June 10-14, 1991.

Meyers, J. F. and Clemmons, J. I., Jr.: Processing Laser Velocimetry High- Speed Burst 

Counter Data. Proceedings of the Third International Workshop on Laser Velocimetry, 

Purdue University, pp 300-313, July 1978.

Meyers, J. F.; and Clemmons, J. I., Jr.: Frequency Domain Laser Velocimeter Signal 

Processor - A New Signal Processing Scheme. NASA TP-2735, September 1987.

Meyers, J. F.; Clemmons, J. I., Jr.; Stoughton, J. W.; Kanetkar, S. V.; and Savakis, A. E.: 

Frequency Domain Laser Velocimeter Signal Processor. United States Patent 4,786,168, 

November 22, 1988. 

References.4
Meyers, J. F.; Couch, L. M.; Feller, W. V.; and Walsh, M. J.: Laser Velocimeter Measurements 

in a Large Transonic Wind Tunnel. Proceedings of the Minnesota Symposium on Laser 

Anemometry, University of Minnesota, pp. 83-111, October 22-24, 1975.

Meyers, J. F.; and Hepner, T. E.: Velocity Vector Analysis in a Juncture Flow Using a Three 

Component Laser Velocimeter. The Second International Symposium on Applications of 

Laser Anemometry to Fluid Mechanics, Lisbon, Portugal, July 2-4, 1984.

Meyers, J. F.; and Hepner, T. E.: Measurement of Leading Edge Vortices from a Delta Wing 

Using a Three Component Laser Velocimeter. AIAA 15th Aerodynamic Testing Conference, 

San Diego, CA, paper AIAA-88-2024, May 18-20, 1988. 

Meyers, J. F. and Hoad, D. R.: Laser Velocimeter Measurements in the Wake Region Behind 

a NACA 0012 Wing. AIAA 14th Thermophysics Conference, Orlando, FL, paper AIAA-79-

1087, Orlando, Florida, June 4-6, 1979. 

Meyers, J. F.; Kjelgaard, S. O.; and Hepner, T. E.: Investigation of Particle Sampling Bias 

in the Shear Flow Field Downstream of a Backward Facing Step. Proceedings of the Fifth 

International Symposium on Applications of Laser Anemometry to Fluid Mechanics, 

Lisbon, Portugal, paper 29.1, July 9-12, 1990.

Meyers, J. F.; and Murphy, R. J.: Frequency Domain Laser Velocimeter Signal Processor. 

Technology 2000, NASA, Washington, DC, November 27-28, 1990. 

Meyers, J. F.; and Stoughton, J. W.: Frequency Domain Laser Velocimeter Signal Processor. 

Laser Anemometry in Fluid Mechanics III - Selected Papers from the Third 

International Symposium on Applications of Laser Anemometry to Fluid 

Mechanics, editors: R. J. Adrian, D. F. G. Durao, F. Durst, H. Mishina and J. H. Whitelaw, 

LaDoan-Instituto Superior Tecnico, Lisbon, Portugal, pp. 83-102, 1988. 

Meyers, J. F.; Usry, J. W.; and Miller, L. S.: Assessing the Capabilities of Doppler Global 

Velocimetry to Measure Vortical Flow Fields. Journal of Aerospace Engineering, part G, 

vol 208, pp. 99-105, December 1994.

Meyers, J. F.; and Walsh, M. J.: Computer Simulation of a Fringe Type Laser Velocimeter. 

Proceedings of the Project Squid Workshop on the Use of the Laser Velocimeter for Flow 

Measurements, Purdue University, pp. 471-509, March 27-29, 1974.

Meyers, J. F.; and Wilkinson, S. P.: A Comparison of Turbulence Intensity Measurements 

Using A Laser Velocimeter and A Hot Wire In A Low Speed Jet Flow. Proceedings of the 

International Symposium on Applications of Laser- Doppler Anemometry to Fluid 

Mechanics, Lisbon, Portugal, paper 17.4, July 5-7, 1982.

Mie, G.: Optics of Turbid Media. Ann. Phys., vol. 25, no. 3, pp. 377-445, 1908.

References.5
Nichols, C.E., Jr.: Preparation of Polystyrene Microspheres for Laser Velocimetry in Wind 

Tunnels. NASA TM-89163, June 1987.

Pike, E. R.: The Application of Photon-Correlation Spectroscopy to Laser Doppler 

Velocimetry. The Use of the Laser Doppler Velocimeter for Flow Measurements, 

W. H. Stevenson and H. D. Thompson, eds., Contract N00014-67-A0226-055, Purdue Univ.,

 pp. 338-347, Nov. 1972.

Pike, E. R.: The application of photon correlation spectroscopy to laser Doppler 

measurements. Journal of Physics D: Applied Physics, Vol. 5, pp. L23-L25, 1972.

Rudd, M. J.: A Self Aligning Laser Doppler Velocimeter. ICO-8, Optical Instruments and 

Techniques, Oriel Press, 58-166, 1969.

Rhodes, D. B.: Optical Scanning System for Laser Velocimeter. SPIE vol. 84, Laser 

Scanning Components & Techniques, 1976.

Rudd, M. J.: A New Theoretical Model for the Laser Dopplermeter. Journal of Scientific 

Instruments, pp. 55-58, Series 2, Vol. 2, 1969.

Sasaki, O.; Sato, T.; Abe, T.; Mizuguchi, T.; and, Niwayama, M.: Follow-up-type laser 

Doppler velocimeter using single-mode optical fibers. Applied Optics, Vol. 19(8), pp. 1306-

1308, April 15, 1980.

Tropea, C.: Laser Doppler Technique. Springer Handbook of Experimental Fluid 

Mechanics, Tropea, C.; Yarin, A. L.; and Foss, J. F. (Eds.), Springer, Berlin, chap. 5.3.2., 

pp. 296-309, 2007.

vom Stein, H. D. and Pfeifer, H. J.: A Doppler difference method for velocity measurements. 

Metrologia 5, 59-61, 1969.

vom Stein, H. D. and Pfeifer, H. J.: An Automatic Data Processing System for Laser 

Anemometers. The Use of the Laser Doppler Velocimeter for Flow Measurements, W. H. 

Stevenson andH. D. Thompson, eds., ContractN00014-67-A0226-055, Purdue Univ., pp. 

123-132, Nov. 1972.

Young, W. H., Jr.; Meyers, J. F.; and Hepner, T. E.: A Laser Velocimeter Survey Above a 

Stalled Wing. TN D-8408, August 1977.

Yule, G. U.; and Kendall,M. G.: An Introduction to the Theory of Statistics. Charles 

Griffin & Co., Ltd., 1940.

Yeh, Y.; and Cummins, H. Z.: Localized Fluid Flow Measurements with an He-Ne Laser 

Spectrometer. Applied Physics Letters,Vol. 4, pp. 176-178, May 1964.

References.6
Young, W. H., Jr.; Meyers, J. F.; and Hoad, D. R.: Laser Velocimeter Data Interpretation by 

Histogram and Spectral Analysis. USACDEC 23rd Conference on the Design of 

Experiments in Army Research, Development and Testing, Monterey, CA, October 1977. 

Young, W. H., Jr.; Meyers, J. F.; and Hoad, D. R.: A Laser Velocimeter Flow Survey Above a 

Stalled Wing. NASA TP-1266, December 1978. 

References.7
References.8
Appendix A

Monte Carlo Simulation of a

Laser Velocimeter

The determination of the measurement accuracy for any instrumentation system, 

including laser velocimetry, requires knowing the actual value being measured. In the real 

world this is accomplished by comparing one instrument against another – supposedly a 

trusted measurement, but is it really accurate? This was the question laser velocimetry 

researchers were asked in the early days. Do you obtain the same mean velocity 

measurements as a Pitot probe? Then, how did your turbulence measurement compare 

with hot wire? The counter response was typically, And how do you know the Pitot probe 

(or hot wire) measurements were accurate? No one really knows. In the early days it was 

not readily accepted that light could be used to measure flow velocities better than the 

standard time-tested techniques. It seemed to be a no win situation because: 1) if the 

laser measurements matched the Pitot tube and hot wire results, then why invest in this 

new technology?, and 2) If it did not match, then what? Recognizing this Catch 22, Meyers 

and Walsh (1974) undertook a different tack: Could the laser velocimeter be theoretically 

evaluated? And further, could a particle be tracked through a flow field to determine its 

ability to follow that flow with fidelity? This early work was based on several poor 

assumptions and a lack of understanding of the physics involved in laser velocimetry. Two 

major breakthroughs occurred at the 1975 Minnesota Symposium on Laser Anemometry 

that provided the insight needed. Ron Adrian (Adrian and Earley (1975)) presented the 

description of the interferometric interactions of two light waves scattered by a particle 

passing through a laser velocimeter measurement volume. The interaction of the two Mie 

scattering wavefronts was far more complicated than most realized. Then Bill Mayo (Mayo 

(1975)) described the entire process of laser velocimetry as a series of random events. A 

particle arrives at the measurement volume at a random time (Poisson) with a random 

velocity trajectory (turbulence) and scatters light in the form of photons which arrive at 

the photomultiplier at random times (Poisson). These two revelations required a major 

rewrite to the laser velocimeter simulation program to include real interference effects in 

the scattered light, and the use of Monte Carlo techniques to introduce randomness in the 

process. Later versions of the simulation program were used in the development of an 

entirely new signal processor that ultimately displaced the high-speed burst counter as the 

state-of-the-art laser velocimeter signal processor (Meyers and Clemmons (1987), Meyers 

et al (1988), Meyers and Murphy (1990)).

The Monte Carlo Technique

The Monte Carlo technique is based on the use of random number generators to model 

some physical phenomenon. The objective is to make use of known physical traits, apply 

the appropriate random number generator and view the result statistically – much the 

same way real measurements are made and analyzed. Although this approach is not 

widely used, it is quite simple in its implementation. It provides a great deal of realism to 

Appendix A.1
the simulation without the assumptions required by most analytical approximations or 

simulations (or as Meyers did in 1971 – through 1975).

In order to visualize how a Monte Carlo simulation is performed, consider light 

illuminating the photo-cathode surface of a photomultiplier and its subsequent generation 

of electric current. The analytic approach would be to determine the power of the light 

striking the photo-cathode in Watts, multiply by the quantum efficiency, multiply by the 

gain of the dynode chain, low-pass filter by the bandwidth of the photomultiplier, and the 

current trace is generated. But wait, there is no noise on the signal leaving the 

photomultiplier. Just add random Gaussian white noise and a realistic signal is generated. 

Well almost, seems that the signal contains negative current part of the time – not possible 

from a photomultiplier. 

In the Monte Carlo approach each process is analyzed and modeled, and moving from one 

small model to the next to the next a signal appears that virtually matches the 

photomultiplier output seen on an oscilloscope. To begin, when light interacts with a 

photomultiplier it does not act as a wave, but a series of photons. In this example the light 

has a constant amplitude of X Watts. In the photon model, x Watts most likely is not a 

continuum (especially if it is scattered light from a particle) as assumed above, but a train 

of photons arriving at the photomultiplier with interarrival times that obey Poisson 

statistics. The average interarrival time is determined by the light power, x Watts, then a 

Poisson random number generator, based on this interarrival time, is used to determine 

the arrival time of each photon. Thus a binary train of pulses would be impacting the 

photo-cathode surface of the photomultiplier. With the binary train defined, how many of 

these photons actually become photo-electrons?

With the completion of the first model, the photon arrival times, the second model begins. 

Instead of multiplying the light power by the quantum efficiency (can't multiply a photon 

train anyway), think of quantum efficiency as a threshold in the range from 0 to 1. 

Assume the quantum efficiency is 20-percent, so on average 1 photon in five would become 

a photo-electron, but which one? The answer is provided by using a uniform random 

number generator to pick a number between 0 and 1 each time a photon arrives. If the 

random number is 0.2 or less, the photon becomes a photo-electron. The train of photoelectrons, which is now sparser than the photon train, still obeys the random statistics 

found in the real world.

The third model is actually not a random process, but does rely on the randomness of the 

train of photo-electrons to yield the signal. The process of converting the photon to a 

photo-electron requires a bit of time, nominally 5 nsec for an average photomultiplier. This 

could be approximated by a triangle to model the impulse response of the photomultiplier. 

If a second photon arrives during the same time as the first, its 5 nsec triangle is just added 

to the first, only delayed by the difference in the arrival times. This process is referred to 

as photon pile-up (Mayo (1975)). 

Appendix A.2
The next and final stage of this simulation is the passage of the signal through the dynode 

chain. Instead of just multiplying the now filtered photo-electron signal by the gain, the 

signal is amplified by each dynode with a mean and standard deviation attributed to the 

availability of electrons being present on the dynode. The multiplication factor is not 

constant, but an average gain with a standard deviation that can be simulated with a 

Gaussian random number generator operating on the signal in time. Thus the signal 

exiting the photomultiplier model is all positive and exhibits the noisy characteristics that 

can be found in the real world. Figure A.1 was a capture of two particles passing through 

the laser velocimeter measurement volume – the first passed near the center which 

exhibits the classic signature, while the second, which passed through the edge, was photon 

resolved. As a comparison consider a simulation of these two particles using Monte Carlo 

techniques, Figure A.2.

Over time the simulation has become more sophisticated in its continued development 

since the original Monte Carlo simulation in 1975 (See Figure 4 in Mayo (1975)). Although 

its development was completed in the mid 1980's, its selection to aid in the development of 

upgrades to the 14- by 22-Foot Laser Velocimeter, and advances in computer technology 

provided the stimulus to overhaul the code. The development of a graphical user interface, 

simulation of two measurement components, replacement of high-speed burst counter 

processing with signal capture / frequency domain processing, and signal display 

capabilities increased the utility of the code while keeping the fundamental processes of the 

original code. Additionally models for the air flow and particle size distributions were 

strengthened for increased capability. Remember, even with this increased sophistication, 

Monte Carlo simulation techniques are inherently simple – just breakdown a process into 

its smallest pieces which can then be modeled without assumptions. By taking a signal 

from one process to the next, to the next, etc., the real effects a device has on the physics 

are imposed on the signal. That is why many of the error sources found in laser 

velocimetry research were also present in the simulation results.

The current Monte Carlo simulation had three purposes during the development of the 

upgrades for the 14- by 22-Foot Subsonic Tunnel laser velocimeter: 1) determine if the 

upgraded optical system would yield signals sufficient in strength to measure; 2) provide 

signals that would serve as benchmarks in the development of an accurate signal 

processing algorithm; and, 3) provide signals that would drive an arbitrary waveform 

generator to test and evaluate the upgraded data acquisition/signal processing 

hardware/software. To help expedite the development of the signal processing algorithm, 

the processing program was appended to the simulator, with the key algorithm under test 

added as a subroutine with a common call statement. The simulator was written using 

Intel Fortran 90, with graphics routines from the GrWin graphics library by Tsuguhiro 

Tamaribuchi, (http://spdg1.sci.shizuoka.ac.jp/grwinlib/english/). The following is an 

explanation of the data entry screens for the program.

Appendix A.3
Simulation Program Data Entry Screens

When the program is started the user will be presented with a series of screens for the 

entry of the physical characteristics of the laser velocimeter, seeding particles, the test flow, 

and several program output parameter settings. The program will present the settings 

from the previous execution, unless this is the first execution on a given computer when a 

default set of parameters is loaded. Once all the parameters have been set, they will be 

stored in the program's initialization file to be presented at the next execution of the 

program. (This program was developed by James F. Meyers while serving as a 

Distinguished Research Associate at the NASA – Langley Research Center and was 

copyrighted in 2008. Under the DRA agreement, this program is available for use by 

NASA – Langley Research Center at no cost.) An overview is given in Chapter III.

Screen 1: Figure A.3. - Laser Velocimeter Simulation 

LV Sim INI file: Program start-up file. If a file other than that presented is desired, click 

on the gray box and a file manager will be presented where the file may be selected. If a 

new file is to be built, click on the gray box next to New INI file?, and then click on the 

long gray box and the full path and file name can be entered. This new file will be created 

and the program parameter settings will be stored in it.

Click Next when ready to continue, Exit to terminate the program.

Screen 2: Figure A.4. - LV Simulation – Transmitter

Laser Wavelenth, μm: (λU and λV) Click on the box below U-component and 

V-component and enter the laser wavelength in micrometers for each component.

Laser Power, W: (PU and PV) Click on the appropriate box and enter the laser power in 

Watts, available to each component. This is a carryover from the classic system when a 

prism was used to separate the laser wavelengths before the splitting optics and the laser 

power in each color could be measured. With the current system the beam powers leaving 

the final lens should be measured and the component beam powers added with the results 

inserted here.

Bragg Frequency, MHz: (FBraggU and FBraggV) Click on the appropriate box and enter 

the Bragg cell drive frequency for each component in MegaHertz.

Beam 1 Location (X,Y), m: (B1XU, B1YU, B1XV, and B1YV) Click on the appropriate box 

and enter the X and Y locations of a laser beam at the final lens. The position X = 0, Y = 0 

is the center of the lens (optical axis), and X (horizontal) and Y (vertical) are measured 

looking out from the lens toward the measurement volume in meters.

Appendix A.4
Beam 2 Location (X,Y), m: (B2XU, B2YU, B2XV, and B2YV) Click on the appropriate box 

and enter the X and Y locations of the other laser beam at the final lens. NOTE: The 

order of the two beams is immaterial. The position X = 0, Y = 0 is the center of the lens 

(optical axis), and X (horizontal) and Y (vertical) are measured looking out from the lens 

toward the measurement volume in meters. 

Transmission (Beam 1,2): (T1U, T2U, T1V, and T2V) Click on the appropriate box and 

enter the decimal fraction of the total power exiting each beam. Measure the output power 

of each beam comprising a component and determine the fraction of the total power 

contained within the input beam for that component. Since the output beams are 

measured in the current system, the fraction would be the power in that beam divided by 

the sum of both beams.

Polarization (Beam 1,2), degrees: (φ1U, φ2U, φ1V, and φ2V) Click on the appropriate box 

and enter the polarization of each beam. Vertical polarization is 90.0 degrees and 

horizontal polarization is 0.0. The polarization for each beam should be measured as these 

parameters are critical in the Mie scattering calculations and the resulting interference at 

the photomultiplier.

Laser Beam Diameter, m: (d) Click on the appropriate box and enter the diameter of 

the laser beam at the final lens in meters. It is assumed that all four beams have the same 

diameter.

Focal Distance, m: (FT) Click on the appropriate box and enter the distance from the 

final lens to the measurement volume in meters.

It is assumed that the laser beams are parallel entering the final lens, and that each laser 

beam is collimated. Thus the beams would cross at the focal length of each beam, i.e., the 

fringes are parallel. The diameter of the beam focus is assumed to be diffraction limited. 

It is further assumed that there are no chromatic aberrations in the optics so that both 

component measurement volumes are at the same location in space.

Click Next when ready to continue, Exit to terminate the program.

Screen 3: Figure A.5. - LV Simulation – Receiver

Focal Distance, m: (FR) Click on the appropriate box and enter the distance from the 

measurement volume to the collecting lens in meters. This would be the same distance as 

the transmitter focal length for a coaxial backscatter configuration.

Alpha View, deg: (αR) Click on the appropriate box and enter the vertical angle of the 

collecting lens above/below the transmitter optical axis in degrees. A coaxial backscatter 

configuration would have a vertical angle of zero degrees.

Appendix A.5
Theta View, deg: (θR) Click on the appropriate box and enter the horizontal angle of the 

collecting lens about the transmitter optical axis in degrees. A coaxial backscatter 

configuration would have a horizontal angle of 180 degrees.

Effective Lens Diameter, m: (dR) Click on the appropriate box and enter the effective 

diameter of the collecting lens in meters. The effective diameter is the diameter at the 

collected lens of the scattered light cone that passes through all lenses, apertures, etc. in 

the receiver and reaches the photomultiplier.

Sample Rate, MHz (0 = Auto) Click on the appropriate box and enter the sampling rate 

of the high-speed digitizer in Mega Hertz. Entering a 0 will automatically set the sampling 

rate to obtain 10 samples per cycle of the Doppler signal based on the Bragg shift input 

parameter.

Transmission (receiver efficiency): (TRU and TRV) Click on the appropriate box and 

enter the transmission fraction of the receiver optical system for that component. Fraction 

of the collected scattered light reaching the photomultiplier for the U- and V-component, 

respectively.

PMT Quantum Efficiency: (η) Click on the appropriate box and enter the 

photomultiplier quantum efficiency as a decimal fraction.

PMT Gain, M: (G) Click on the appropriate box and enter the photomultiplier gain in 

millions.

System Gain, dB: (GS) Click on the appropriate box and enter any extra electronic 

system gain by amplifiers following the photomultiplier in decibels.

High Pass Filter, MHz: (HPFU and HPFV) Click on the appropriate box and enter the 

high pass filter break point frequency in Mega Hertz. A high pass filter is used primarily 

to remove the pedestal from the signal burst. 

Low Pass Filter, MHz: (LPFU and LPFV) Click on the appropriate box and enter the low 

pass filter break point frequency in Mega Hertz. A low pass filter is used primarily to 

remove the high frequency noise associated with photon pile-up and the Gaussian noise 

found in the dynode chain amplification process.

Click Next when ready to continue, Exit to terminate the program.

Screen 4: Figure A.6. - LV Simulation – Particles and Flow

Refractive Index – Real: (RIreal) Click on the appropriate box and enter the real part of 

the particle index of refraction, e.g., PSL = 1.59, water = 1.33.

Appendix A.6
Refractive Index – Img: (RIimg) Click on the appropriate box and enter the imaginary 

part of the particle index of refraction, e.g., ploystyrene latex, water, liquids = 0.0, carbon 

and metals have an imaginary refractive index.

Start/Single Size, micron: (PARLow) Click on the appropriate box and enter the desired 

particle size (provided the Single Size box is checked), or the smallest particle size in the 

selected distribution.

End Particle Size, micron: (PARHigh) Click on the appropriate box and enter the largest 

particle size. If the Single Size box is checked, this box will not respond.

Data Rate, #/sec: Click on the appropriate box and enter the average number of 

particles per second to pass through the measurement volume. NOTE: This feature is 

disabled at this point since it is used as a tool to develop turbulence power spectra 

algorithms and to simulate other time dependent characteristics of the flow.

Single Size: Click on the appropriate box to select single particle size input – other 

selections will be turned off by this selection. The desired particle size should be placed in 

the Start/Single Size entry.

Uniform Distribution: Click on the appropriate box to select a uniform particle size 

distribution – other selections will be turned off by this selection. The smallest desired 

particle size should be placed in the Start/Single Size entry, and the largest desired 

particle size should be placed in the End Particle Size entry.

1/r3 Distribution: Click on the appropriate box to select a Junge (power law) type 

particle size distribution – other selections will be turned off by this selection. The 

smallest desired particle size should be placed in the Start/Single Size entry and the 

largest desired particle size should be placed in the End Particle Size entry. The Junge 

distribution describes the distribution of aerosols in the atmosphere and is a power law 

distribution approximating 1/r3 extending from 0.4- to 1.5-micron with a particle number 

density of 760 particles per cubic centimeter at the ocean shore down to 460 particles per 

cubic centimeter inland. If this distribution is selected the input particle size limits are 

mapped to the probabilities of the Junge distribution.

Gaussian Distribution: Click on the appropriate box to select a Gaussian particle size 

distribution – other selections will be turned off by this selection. The smallest desired 

particle size should be placed in the Start/Single Size entry and the largest desired 

particle size should be placed in the End Particle Size entry. The desired particle sizes 

will set the lower and higher standard deviations of the distribution. Random particles will 

be selected from ±3 standard deviations about the mean. Particles less than 0.1-micron 

will be ignored.

Appendix A.7
Number of Particles: Click on the appropriate box and enter the number of particles to 

be passed through the measurement volume.

Mean Velocity, m/s: and Std Deviation, m/s: (VELmag and σmag) Click on the Mean 

Velocity box and enter the desired average velocity magnitude. Click on the 

corresponding Standard Deviation box and enter the desired standard deviation. The 

velocity magnitude will obey Gaussian statistics.

Mean Alpha, deg: and Std Deviation, deg: (α and σα) Click on the Mean Alpha box 

and enter the desired average vertical flow angle. Click on the corresponding Standard 

Deviation box and enter the desired standard deviation. The vertical flow angle will obey 

Gaussian statistics.

Mean Beta, deg: and Std Deviation, deg: (β and σβ) Click on the Mean Beta box and 

enter the desired average horizontal flow angle. Click on the corresponding Standard 

Deviation box and enter the desired standard deviation. The horizontal flow angle will 

obey Gaussian statistics.

Signal Threshold, V: (THRES) Click on the appropriate box and enter the voltage 

setting that will trigger a signal capture and the succeeding signal processing.

Full Scale A/D, V: (FS) Click on the appropriate box and enter the full scale voltage for 

the 8-bit analog-to-digital converter. The full scale voltage follows the 1, 2, 5, 10 sequence 

and is bi-directional, e.g., an entry of 1.0 will set the A/D converter to measure voltages in 

the range ±1.0 V.

Save Histogram Plots? Click on the appropriate box to save the plots of all distributions 

presented as Extended Windows Metafiles (EMF) in the directory that contains the 

program setup file (INI – selected in Screen 1).

Auto Display Plots? Click on the appropriate box to automatically display the resultant 

plots for 15 seconds, then display the next set of plots, etc. If this box is not selected, the 

user must manually change sets of plots by moving the cursor to the upper left plot where 

the arrow cursor will change to a +. A left mouse click will display the next set of plots.

Trigger Mid Burst? Click on the appropriate box to configure the signal capture register 

to pretrigger mode making the trigger occurrence to be at the 40-percent register address 

in order to capture the entire signal burst. If the box is not selected, the trigger occurrence 

will be at the beginning register address, e.g., normal oscilloscope triggering.

Downmix Signal? Click on the appropriate box to pass the filtered signal burst through 

a double-balanced mixer before being digitized by the A/D converter.

Appendix A.8
U-Downmix Freq, MHz: Click on the appropriate box and enter the reference frequency 

for the double-balance mixer – U-component signal burst, e.g., an entry of 30 MHz will 

yield an effective Bragg frequency of 10 MHz from a signal burst shifted by a 40 MHz 

Bragg cell. The difference frequency is output to the A/D converter. Note: This entry is 

not available unless the Downmix Signal has been selected.

V-Downmix Freq, MHz: Click on the appropriate box and enter the reference frequency 

for the double-balance mixer – V-component signal burst, e.g., an entry of 30 MHz will 

yield an effective Bragg frequency of 10 MHz from a signal burst shifted by a 40 MHz 

Bragg cell. The difference frequency is output to the A/D converter. Note: This entry is 

not available unless the Downmix Signal has been selected.

Save PMT Signals? Click on the appropriate box to save the signal traces from the 

photomultiplier output. Each signal burst is saved as a three column text file with the 

name SimSignalsxxxxx.TXT, where xxxxx represents the particle number. The first 

column is time in microseconds with 0.0 being located at the center of the signal burst. 

The second column is the U-component signal, and the third column is the V-component 

signal. The file heading includes the particle's trajectory and velocity magnitude and flow 

angles along with the U- and V-component velocities. NOTE: Once selected, any other 

save signal selection will be turned off. If it is desired to turn off signal trace recording, 

click the selected save option and it will be turned off.

Save High-Pass Signals? Click on the appropriate box to save the signal traces 

following high-pass filtering of the photomultiplier output. Each signal burst is saved as a 

three column text file with the name SimSignalxxxxx.TXT, where xxxxx represents the 

particle number. The first column is time in microseconds with 0.0 being located at the 

center of the signal burst. The second column is the U-component signal, and the third 

column is the V-component signal. The file heading includes the particle's trajectory and 

velocity magnitude and flow angles along with the U-and V-component velocities. NOTE: 

Once selected, any other save signal selection will be turned off. If it is desired to turn off 

signal trace recording, click the selected save option and it will be turned off.

Save Triggered Signals? Click on the appropriate box to save the signal traces that 

triggered the data acquisition system. Each signal burst is saved as a three column text 

file with the name SimSignalxxxxx.TXT, where xxxxx represents the particle number. The 

first column is time in microseconds with 0.0 being located at the center of the signal 

burst. The second column is the U-component signal, and the third column is the 

V-component signal. The file heading includes the particle's trajectory and velocity 

magnitude and flow angles along with the U-and V-component velocities. NOTE: Once 

selected, any other save signal selection will be turned off. If it is desired to turn off signal 

trace recording, click the selected save option and it will be turned off.

Save A/D Captures? Click on the appropriate box to save the digitized signal trace. This 

signal is the input to the signal processing software. Each signal burst is saved as a three 

Appendix A.9
column text file with the name SimSignalxxxxx.TXT, where xxxxx represents the particle 

number. The first column is time in microseconds with 0.0 being located at the center of 

the signal burst. The second column is the U-component signal, and the third column is 

the V-component signal. The file heading includes the particle's trajectory and velocity 

magnitude and flow angles along with the U-and V-component velocities. NOTE: Once 

selected, any other save signal selection will be turned off. If it is desired to turn off signal 

trace recording, click the selected save option and it will be turned off.

Click Run when ready to run the program, Exit to terminate the program. An example 

set of input data is presented in Table A-1.

The Simulation

As illustrated above a Monte Carlo simulation breaks a large process into small parts 

which can be simulated using the physical processes involved in that element. The 

simulation of a laser velocimeter is a mixture of analytical descriptions of the optical 

system and the Monte Carlo descriptions of the particle trajectories and signal 

development. The following will address these areas and provide the reader with the 

methodology involved in the simulation.

The Laser Velocimeter Optical System

The input geometric configuration of the laser velocimeter is used to determine the 

characteristics of the collected scattered light from particles passing through the 

measurement volume. There are several assumptions made in the program that should 

not significantly affect the predictions, but significantly reduce the complications in both 

the program and the optical system. The assumptions that are the most difficult to obtain 

in a real optical system are diffraction limited optics with no spherical or chromatic 

aberrations. The assumptions that all beams are perfectly collimated and parallel as they 

enter the final lens are obtainable with properly designed systems. 

The first task is to compute the cross beam angle for each component. While this may 

appear to be a simple task, it is complicated by the fact that the simulation is designed to 

configure not only an orthogonal, two color system, but the three-beam polarization and 

the four-beam Bragg shifted single color configurations as well. This is followed by the 

calculation of the receiver location and collecting solid angle of acceptance for each input 

laser beam. These calculations are needed to determine the Mie scattering characteristics.

Characteristics of the Collected Scattered Light

Now that the geometric optical characteristics have been determined, the characteristics of 

the collected scattered light must be determined. The complex electro-magnetic field 

characteristics of light scattering from particles whose diameter is approximately the 

wavelength of the illuminating radiation was described by Mie (1908). This theory was 

Appendix A.10
Lmv =

 2 Dbw cos



2

sin 

Abw =

 Dbw

2

4

enhanced by Adrian and Earley (1975) when they described the interactions of two 

scattering fields obtained when a particle passes through two crossing coherent laser 

beams. The current simulation utilizes the theoretical predictions by Adrian and Earley to 

obtain the complex scattering characteristics by dividing the collecting solid angle into a 

1024x1024 grid. The pedestal amplitude from each beam, signal amplitude, and relative 

phase are determined for each grid point within the collected solid angle and zeroed 

otherwise. Examples of the Mie scattering characters are shown for the laser velocimeter 

specifications presented in the data entry screens for 0.5-microns (Figure A.7), 1.0-micron 

(Figure A.8), 1.7-microns (Figure A.9), 2.0-microns (Figure A.10), and 3.0-microns 

(Figure A.11). The effects of non-orthogonal polarizations (Figure A.4) can be found at the 

top and bottom of the U-component grids. These figures also include the distribution of 

power and signal strength along with the resulting photomultiplier output signal bursts, 

high-pass filtered signal bursts and frequency spectra of the burst. Once developed, the 

non-zero elements of the grid are averaged to produce the average pedestal amplitude 

contribution from each laser beam, the average signal level, and average phase angle.

Instead of performing these time consuming computations for each particle passing 

through the measurement volume, the particle size distribution is divided into 0.1-micron 

steps and the Mie scattering characteristics determined once for each particle size. The 

errors generated by particles passing through the measurement volume with different 

trajectories, and thus producing slightly different solid angles, are considered negligible 

based on comparisons of the grid patterns for various trajectories of the same particle. A 

table is constructed from the results of the computations that contains the average 

pedestal power for each beam, the average signal level and the average phase angle as a 

function of particle size.

The Flow Simulator

Once the tables containing the Mie scattering parameters have been developed for the 

input particle size range, the flow simulator proceeds to determine the size of the 

measurement volume to lay out the acceptance plane for the particle passages. Assuming 

diffraction limited optics, the beam waist, length of the measurement volume and cross 

sectional area of the measurement volume can be determined using the equations below:

(A.1)

(A.2)

(A.3)

where Dbw is the beam waist diameter of focused laser beam, and if aligned properly, the 

diameter of the measurement volume, λ is the laser wavelength, F is the focal distance of 

Appendix A.11

Dbw =

4 F

d
RN U n1  = RN Un∗29.0−INT RN Un∗29.0

the transmitter, d is the diameter of the laser beam at the final lens, Lmv is the length of 

the measurement volume, θ is the angle between the crossing laser beams, and Abw is the 

cross sectional area of the focused laser beam at the beam waist.

Random Number Generators:

At this point the program deviates from the analytic development of Mie scattering and 

laser velocimetry geometry into the world of Monte Carlo. The base of all random number 

generators is the uniform generator which selects a number from 0 to 1 with equal 

probability. There are numerous equations that provide this capability and even most 

computer languages contain a generator in their math library. As an example, consider the 

following procedure:

Select a 10 digit decimal fraction that contains all digits 0 to 9 in an arbitrary order as a 

seed, RNU0 and apply the equation:

(A.4)

where INT is the integer function. As an example, use the seed: 0.2510637948 to obtain 

the following sequence: 0.28, 0.14, 0.19, 0.65, 0.90, 0.20, 0.85. Since all random number 

generators will eventually repeat, the more digits available while solving equation A.4 will 

increase the number of random numbers that will occur before repeating. Therefore 

double precision is recommended. The current simulator uses the random number 

generator in the FORTRAN 90 library. It does not appear to repeat and is optimized for 

speed.

The most commonly used generator based on the Uniform generator is the normal or 

Gaussian random number generator. Starting with the uniform random number 

generator, the following equation is applied to convert the uniform random number to a 

Gaussian random number:

(A.5)

where RNG is the Gaussian random number and RNUn and RNU(n+1) are two successive 

uniform random numbers. The generator has a mean of 0.0 with a standard deviation of 

1.0, thus an offset must be added to obtain the desired mean and a multiplying factor to 

obtain the desired standard deviation. This algorithm is used in the simulation program.

While the Gaussian generator provides simulations ranging from grades on a test, to the 

heights of people in a group, to household incomes, to velocity in a wind tunnel, it can not 

predict interarrival times of occurrence because time can not be negative. Interarrival 

times from the passage of cars on a highway to the arrival of photons at a photomultiplier 

can, however, be modeled with a Poisson distribution. Again using random numbers from 

the uniform random number generator, a Poisson random number generator can be 

constructed using the following equation:

Appendix A.12

RN G = −2.0 logRN Un cos2 RN U n1
(A.6)

where Xn > 0.0. A more robust method that allows for the overall shape variation to fit 

known characteristics of the random process being modeled is given by the procedure 

below:

(A.7)

where λP is the shape factor, (a value of 4 approximates the statistics for the time between 

photon arrivals at a photomultiplier, and particle arrivals at the laser velocimeter 

measurement volume), and RNUn is the uniform random number. Poisson distributions 

are always positive and the standard deviation is the same as the mean. This algorithm 

will produce a mean and standard deviation equal to 1.0 and is used in the simulation 

program.

The final random number generator used in the simulator models the Junge (power law) 

distribution (Junge (1955)) which approximates the distribution of aerosol particles in the 

atmosphere. The aerosol distribution extends from 0.4- to 1.5-microns in a 1/r3 power 

form. This distribution also approximates the distribution found in many 

vaporization/condensation generators, except the particle size limits are different. The 

procedure used to generate the random number and scale it to the desired particle size 

range is given below:

(A.8)

where RNUn is the uniform random number, RNJ is the random number based on the 

Junge distribution from 0.4- to 1.5-microns, and RNJ-scaled is the scaled random number for 

the particle size limits Pmin to Pmax. This algorithm is used in the simulation program.

Appendix A.13

RN P = log

1.0

RN Un 

Initialization: Test = e

−P

, P = 4.0, k = 0, m = 1

Do: k = k1

m = m RN Un

While: m  Test

Return: k−1

Y = 0.81 RN Un0.019

RN J = e

logP min−logY 

3.0

RN J−scaled =

RN J−Pmin∗Pmax−Pmin

1.5−P min

Pmin
Particle Velocity and Trajectory Through the Measurement Volume:

Once all of the support components are in place, a particle is chosen and assigned a velocity 

and trajectory, then launched through the measurement volume. The size of the particle is 

determined using the random number generator configured using settings defined by the 

user in data entry screen 4 (Figure A.6):

Single Size – User input the desired particle size (Fixed size);

Uniform Distribution – Equal probability from the user input smallest size to the 

largest size (Uniform random number);

1/r3 Distribution – Junge type distribution from the user input smallest size 

to the largest size (Junge random number);

 Gaussian Distribution – Gaussian distribution with the input smallest and largest 

sizes establishing the ±standard deviation about the 

central size (Gaussian random number obtained within 

±3 standard deviations).

The velocity magnitude, vertical flow angle (Alpha), and horizontal flow angle (Beta) are 

determined using the Gaussian random number generator, each parameter established by 

the mean and standard deviation settings entered in data entry screen 4. The uniform 

random number generator is used to determine the vertical (Y) and on-axis (Z) particle 

entry point into the measurement volume. The limits of 0 to 1 in the uniform random 

number generator are mapped to the locus of the 1/e3 power locations:

(A.9)

where DbwU is the beam waist diameter (equation A.1), θ is the angle between the two 

crossing laser beams, Xenter is -0.75 DbwU to always launch the particle at the -1/e3 power 

location along the streamwise direction with the exit plane location, Xexit, set symmetric at 

0.75 DbwU, and Yenter and Zenter are mapped to the uniform random numbers as follows:

(A.10)

Appendix A.14

X =

X enter DbwU

2.0 cos

U

2.0 

Y =

Y enter DbwU

2.0

Z =

 2.0Zenter DbwU cos

U

2.0 

2.0 sin U 

Yenter = 3.0 RN Un − 1.5

Zenter = 3.0 RN U n1 − 1.5
where RNUn and RNU(n+1) are two successive uniform random numbers. This will yield 

random entrance points within the 1/e3 power locations defined as ±0.75 DbwU 

(equation A.1) in the vertical direction, and ±0.75 Lmv (equation A.2) in the on-axis 

direction. 

With the particle's characteristics selected by the random number generators, it is placed 

in the entrance plane at its random location and launched with the random velocity 

magnitude along a trajectory established by the random flow angles. As the particle passes 

through the measurement volume it will scatter laser radiation whose power is dependent 

on the fringe spacing and Bragg shift of the respective velocity component. The fringe 

spacing is established using equation (2) and the parameters entered in data entry screen 2 

(Figure A.4). 

(2)

The Bragg shift frequencies are also entered in data entry screen 2 for each component 

respectively. The ideal U-component signal burst can now be determined based on the 

particle's characteristics and launch point from the following sequence:

(A.11)

where X is streamwise, Y is vertical, Z is along the optical axis (equation A.9), and φα, 

φβ, and φγ are the three trajectory angles: vertical, horizontal, and rotation about the 

optical axis of the laser velocimeter transmission system, respectively. Next the particle 

transit time, Ttransit, between the entrance and exit planes is determined along with the 

effective number of fringes crossed, Nfringes: 

(A.10)

Appendix A.15

l f=



2 sin 



2



 = atan

Yexit−Y enter

X exit−X enter 

= atan

Y exit−Y enter

1.5DBW 

 = atan

Zexit−Zenter

X exit−Xenter 

= atan

Y exit−Yenter

1.5 DBW 

 = atan

Zexit−Zenter

Yexit−Y enter 

TTransit =

1.5Dbw

VELmag

N fringes =

Dbw cos

l fU

 FBraggU TTransit
PVEL XU = VELmag cos( φα ) cos(φβ)

PVELYU = VELmag sin ( φα ) cos(φβ)

K U = 2π(

PVEL XU

l fU

+ FBraggU )

PavgU =

2 PU (T1U + T2U )

Abw

k U =

2π

λU

where VELmag is the particle velocity magnitude and FBraggU is the Bragg frequency for 

the U-component.

The constants needed to determine the ideal signal burst based on the input and randomly 

selected parameters are then determined:

(A.11)

where PVELXU and PVELYU are the horizontal and vertical particle velocities, KU is the 

U-component signal frequency including the Bragg cell frequency, PavgU is the average 

U-component laser power illuminating the measurement volume, and k U is the particle 

scale factor used in the Mie scattering calculations. 

The particle is launched at the entrance plane, location Xenter, Yenter, Zenter, with a velocity 

magnitude, VELmag, and flow angles φα and φβ. The particle's trajectory is reduced to 

components ∆x, ∆y, and ∆z which represent the distance traveled within the time 

between data samples. This process continues until the exit plane is reached and the 

particle transit time has been completed. The following procedure generates and then 

stores the ideal signal burst waveform in the array, SU:

Initialization:

(A.12)

Appendix A.16

 X =

Vel mag cos cos

 T

Y =

Vel mag sin  cos

 T

 Z =

Vel mag cossin 

 T

T = 0
PED =

−2.0 X

2  Y2 

Z

2

U

2

4.0 

0.25 DbwU

2

PED = e

PED

SU =

PED∗PavgU

K U

2 T1U PMie1U  T2U PMie2U cosh



2.0 X Z 

0.25 DbwU

2 

 T1U T2U Doppler MieU cosKU T − MieU 

Do:

(A.13)

(A.14)

While:

The same process is repeated, using the appropriate characteristics, to create the ideal 

V-component signal burst waveform which is stored in the array SV. 

The next task is to convert the two ideal signal bursts to a train of photo-electrons leaving 

the photo-cathode. At each sample of the ideal signal ( P(t) ), given in Watts, the 

following equation is used to determine the number of photons per second ( R(t) ) that 

attain that level:

R(t) = ηλ T R P(t)

hc (A.15)

This rate value is then passed to the Poisson routine to determine the time of the photon's 

arrival at the photo-cathode. The uniform random number generator then generates a 

number. If the number is less than or equal to the photomultiplier quantum efficiency, the 

photon becomes a photo-electron. Otherwise, the photon is rejected. When the total time 

for the photon arrivals exceeds the time for the next sample in the ideal signal, the number 

of photo-electrons occurring in that time increment is stored as the real signal, the next 

signal amplitude sample and its occurrence time is then retrieved and the process repeated 

starting with the arrival of the photon that exceeded the previous sample time and its 

arrival time. This process is described by the logical description below:

Appendix A.17

X = X   X

Y = Y   Y

Z = Z   Z

T = T   T

T  T Transit
TIME =  t T = 0.0

N p = 0

T =

 T R t S Ui

hc RNP  T

RN U  

N P = NP1

T  TIME

SUi = N P

i = i  1

TIME = TIME   t

TIME  TTransit

Initialization:

Do:

Do:

If:

Then: (A.16)

While:

While:

where: ΣTIME Time defined by the sample time

∆t Time between successive digital samples

T Time defined by photon arrivals

Np Number of photons acquired within the ith ∆t

λ Laser wavelength

TR Transmission factor for the LV collecting optics

h Planck's constant

c Speed of light

RNP Poisson random number

RNU Uniform random number

η Photomultiplier quantum efficiency

TTransit Transit time of the particle through the measurement volume.

It is assumed that the number of photo-electrons acquired within a single sample time (∆t) 

occurred simultaneously for the 1.0 GHz input data sample rate. If a slower sampling 

clock is used, the simulation of the photomultiplier impulse response function will be less 

accurate. A captured photo-electron is shown in Figure A.12 (Baker et al (1989)), which 

shows a pulse with a trailing oscillation. The photomultiplier specifications indicate that 

the frequency response of the photomultiplier was 200 MHz, which matches the cycle 

frequency of the captured signal in Figure A.12. The 5.0 nsec cycle time also matches the 

width of the first and primary pulse. Since a photomultiplier is a unipolar device, the 

negative voltages in the figure are likely the result of ringing caused by a mismatch in 

Appendix A.18
impedance between the photomultiplier and the oscilloscope. Thus the simulator uses an 

equilateral triangle with a length of 5.0 nsec to approximate the impulse response of the 

photomultiplier, illustrated by the first pulse in Figure A.12. If the input data sample rate 

is greater than 500 MHz, the signal composed of photo-electrons is convolved with the 

photomultiplier response function, otherwise the signal is untouched.

The signal burst then passes through a high-pass filter to remove the pedestal. This is 

accomplished by applying a Fast Fourier Transform to the signal burst, then using a 

Butterworth high-pass filter set to the input filter break point, Screen 3, Figure A.5 (e.g., 

HPFU):

 

(A.17)

where ∆f is the resolution in the frequency domain, and FSignal is the complex Fourier 

transformed signal burst. The filtered signal is inversely Fourier transformed to yield the 

filtered burst in the time domain. For examples see the signal traces in Figures A.7 – A.11.

If the signal is to be down-mixed, a model of a double-balance mixer is used to obtain the 

difference frequency between the signal burst and the reference frequency. For this model, 

the time domain signal burst is multiplied by a square wave at the reference frequency. 

The resultant signal is Fast Fourier Transformed and low pass filtered with the break 

point set to 50-percent of the reference frequency. The filtered frequency spectra is inverse 

transformed to yield the down-mixed signal burst.

In the next step the signal burst is interrogated to determine if the voltage crosses the 

triggering threshold (THRES, Screen 4, Figure A.6). If the center trigger box was checked, 

the peak voltage is found and a signal limit threshold is determined to be 10-percent of the 

peak voltage. Otherwise the value of the trigger threshold, THRES, is used as the signal 

limit threshold. The signal burst is then interrogated from the start, zeroing each sample 

voltage until the signal limit threshold is crossed. The process is repeated from the end of 

the burst toward the center. The remaining portion of the signal burst is shifted toward 

the beginning of the array with the trailing array locations zeroed. The number of samples 

of the signal burst is then determined and the smallest power of two containing the total 

signal burst is identified. If the number of samples is less than 128, the signal burst is 

rejected. Otherwise the signal is digitized based on an 8-bit digitizer set to the input fullscale voltage, FS (Screen 4, Figure A.6).

This concludes the simulation portion of the laser velocimeter optical system, triggering 

system, and data acquisition electronics. Examples of the various stages of signal 

development are shown in Figures A.13 – A.19. Each example figure includes both the UAppendix A.19

Amp =

 f

4

 HPF U

8   f8

FSignal real = Amp∗FSignal real

FSignal img  = Amp∗FSignal img 
and V-component signals with the U-component signal being used as the triggering burst. 

The theoretical, photomultiplier output, high-pass filtered, and ADC captured signals are 

shown. Ten thousand particles were generated and passed through the measurement 

volume based on a mean velocity magnitude of 100 m/s with a standard deviation of 

3.0 m/s, and a vertical flow angle of 0.0-degrees with a standard deviation of 4.0-degrees. 

The horizontal flow angle was kept at 0.0-degrees. Of these particles, the ones with the 

closest trajectories to the streamwise direction within the plane established by the two 

crossing U-component beams at on-axis locations every 0.5 Lmv (Equation A.2) from 

-1.5 Lmv to 1.5 Lmv were selected for the figures.

Signal and Data Processing

After the filtered signal burst was digitized, the captured signal bursts created by the 

simulator were passed to the signal processing portion of the simulation. Although 

included as part of the laser velocimeter simulation program, in reality the simulator 

served as the development platform for the signal processing and data processing 

algorithms. Further, since the velocity magnitude and trajectory of each particle was 

known, it also served to determine the precision of the algorithms along with the overall 

measurement accuracy.

The first step in the signal processing portion of the program was to determine the extent 

of the signal burst so that a windowing function many be scaled and applied to insure that 

the burst begins and ends at 0.0 V. A Bartlett (triangular) window was used because of its 

simplicity and processing speed. Since the signal burst is basically a sinusoid, the 

characteristics following the frequency break point of the window function are 

unimportant so more sophisticated windowing functions (Hamming, Hanning, Tukey, etc.) 

are not necessary. The only requirement was that there was no discontinuity between the 

beginning and end of the signal burst. This is necessary because the Fast Fourier 

Transform (FFT) algorithm works as if the signal burst was a continual signal – think of 

wrapping the signal burst around a cylinder and rotating it. Any discontinuity will add 

harmonics and noise spikes to the frequency representation of the signal burst that will 

affect the accuracy of the signal processing algorithms.

Once the windowing function has been scaled in time to match the length of the signal 

burst, then scaled in amplitude to have an integral area of unity, the signal burst is 

multiplied by the window. The resulting signal burst is then passed to the signal 

processing subroutine where the first step is to copy the signal burst waveform into the 

real portion of a complex array. The imaginary portion of the complex array is set to 0.0. 

This array is then converted to the frequency domain using a complex FFT utility. The 

real and imaginary parts of the frequency spectra at each frequency step are squared, 

summed and the square root computed to obtain the power spectra. To insure that the 

pedestal has been removed, the first 10 frequency increments are zeroed. The next step is 

to determine the peak location of the frequency signature that indicates the location of the 

signal burst frequency. The amplitude of the peak is then used to determine the signal-tonoise threshold of an acceptable signal. If the background spectral level is greater than 

Appendix A.20
10-percent of the amplitude of the peak, the signal burst is rejected and the returned 

frequency is set to 0.0 to indicate the rejection of the burst. If the signal burst is accepted, 

one of the following processing schemes selected for testing would then be used to 

determine the signal frequency:

Peak The frequency of the peak location is returned.

Gaussian The peak amplitude and the amplitude of the frequency step (bin) 

on either side of the peak are fit with a Gaussian curve and the 

frequency of the peak of the curve fit is returned.

Histogram (3) The peak amplitude and the amplitude of the frequency bin on 

either side of the peak are used as the weights of a weighted 

average of the frequencies for those bins. The weighted average 

frequency is returned.

Histogram (5) The peak amplitude and the amplitude of the two frequency bins 

on either side of the peak are used as the weights of a weighted 

average of the frequencies for those bins. The weighted average 

frequency is returned.

Half Power The peak amplitude is determined and a threshold set to 

50-percent of that amplitude. The amplitude of adjacent frequency 

bins on either side of the peak are interrogated to determine when 

a bin amplitude falls below the threshold. At this point only those 

continuous frequency bins with amplitudes greater than the 

threshold are used as weights of a weighted average of the 

frequencies for those bins. The weighted average frequency is 

returned.

True Half Power This routine is the same as the Half Power routine except the 

amplitudes of the furthermost bin with an amplitude above the 

threshold and the adjacent bin with an amplitude below the 

threshold are interpolated to determine the exact frequency where 

the threshold is crossed. This process is applied to both sides of the 

peak. The weights of this fraction of a bin are scaled with the 

width of the bin fraction. Again these amplitudes along with the 

amplitudes of the bins with amplitudes above the threshold are 

used to determine the weighted average of the frequencies for 

those bins. The weighted average frequency is returned. 

This process is repeated for the V-component signal burst. If both components yield a nonzero frequency, a coincident measurement was successful and the processing continues, 

otherwise this pair of signal bursts are rejected and the next pair of signal bursts are 

processed.

The Bragg (or equivalent Bragg if downmixing was employed) frequencies are subtracted 

from the respective two component frequencies to yield the Doppler shift frequency. The 

frequencies are then converted to velocities using equation (1)

Appendix A.21
(1)

The resultant U- and V-component velocities are then used to calculate the velocity 

magnitude and flow angle of the measured particle. These results, along with the time 

between acceptable signal burst arrivals and its conditionally sampled azimuth angle are 

stored in their corresponding data arrays, and the next signal burst is then processed. This 

loop continues until the selected number of particles have been extinguished.

As the signal processing loop continues, the occurrence of every 100th acceptable pair of 

signal bursts triggers the computation of the ensemble statistics at that point. These 

results will track the convergence of the statistical results toward statistical stationarity. 

Once the selected number of particles have been processed, the final statistics are 

computed, and histograms of velocity and flow angle are developed. The statistical 

quantities computed include the mean, statistical uncertainty in the mean, standard 

deviation, the statistical uncertainty in standard deviation, skew, and excess along with the 

number of signal bursts used in the computations. The histograms are set to bin widths of 

1.0 m/s for the velocities and 1.0 degree for the flow angle. 

Since the simulation program is used for signal processing and data processing algorithm 

development, a record of each event is kept in a LOG file. The LOG begins with the listing 

of the laser velocimeter optical and electronic characteristics along with the particle 

characteristics and flow parameters and the optional settings placed in the data entry 

screens. This is followed by the average Mie scattering pedestal levels for both laser 

beams, the average signal level and average phase angle for the particle size or the range 

requested (in 0.1 micron steps). The table containing the characteristics of each particle 

generated is recorded, Table A-2. These characteristics include:

Particle number and size in microns

Velocity magnitude, vertical flow angle and horizontal flow angle

Trajectory starting location (X, Y, and Z)

Trajectory ending location (X, Y, and Z)

U- and V-component velocities

U- and V-component velocities if the signal burst triggers capture

Measured U- and V-component velocities if successfully processed

U- and V-component velocity errors (velocity of the particle – the measured velocity)

Once all particles have been processed, the mean and standard deviation of the velocity 

magnitude, vertical and horizontal flow angles, U- and V-component velocities, and number 

of signal bursts included in the ensemble are displayed in the command.com window and 

the full statistics (including skew and excess) are recorded in the LOG file, Table A-3. The 

following is displayed and recorded:

Appendix A.22

V =

 f D

2sin 



2


Input particle velocity statistics 

Selected particle velocity statistics (where the signal bursts triggered capture)

Measured velocity statistics

Measurement errors

Next the program displays the various histograms in the graphics window. The first 

window contains the input, triggered, and measured histograms for the velocity magnitude 

and vertical flow angle, Figure A.20. If the auto display option was selected, the 

histograms are displayed for 15 seconds and the next set is displayed, if not the user must 

move the cursor to the upper left histogram and left click the mouse to view the next set. 

The next set contains the input, triggered, and measured histograms for the U- and 

V-component velocities, Figure A.21. The next set of histograms presents the 

measurement errors based on a direct particle-by-particle comparison for the velocity 

magnitude, vertical flow angle and the U- and V-component velocities, Figure A.22. 

After the error histograms have cleared, the program then interrogates the measurement 

histograms searching for outliers. The amplitude of the peak of each histogram is 

determined and used to establish a minimum amplitude threshold of 5-percent of the peak 

(or the value of 3, whichever is greater). If the histogram was a Gaussian distribution, the 

5-percent threshold would equate to the amplitude at the 1/e3 location. Each histogram is 

then tracked toward the right until the bin amplitude goes below the threshold. If the 

amplitude remains below the threshold for three consecutive bins, the point where it falls 

below the threshold becomes the right-hand cutoff. Otherwise the search continues until 

the condition is met. This process is repeated on the left side of the histogram to establish 

the left-hand cutoff. The measurement arrays are then interrogated and any values 

outside their respective cutoffs are eliminated from all arrays. The remaining signal burst 

results are listed in a table in the LOG file in the form of particle number, particle size, 

particle velocity magnitude and flow angle, measured velocity magnitude and flow angle 

and associated measurement errors, U- and V-component particle velocities, U- and 

V-component measured velocities and their associated measurement errors, Table A-4. 

Then the statistics are computed and displayed in the command.com window and recorded 

in the LOG file as:

Measured particle velocity statistics

Outliers Removed

Measurement Errors

and the outlier removed histograms of measured velocity magnitude, vertical flow angle, Uand V-component velocities and U- and V-component measurement errors are displayed, 

Figure A.23. Once this display has completed, the computed velocities and flow angle 

results for each measured signal burst is recorded in the LOG file, Table A-5. The 

characteristics include the particle velocities and flow angles, measured particle velocities 

and flow angles, and the measurement errors in a particle-by-particle listing. The LOG file 

is then closed and the program returns to the second data entry window, LV Simulation – 

Transmitter, Figure A.4. It is noted that if the Save Histogram Plots? box in the 

Appendix A.23
fourth data entry window, Figure A.6, is selected, each of the displayed histogram plots will 

be stored as an independent windows metafile (EMF) in the same directory as the original 

INI file. Also if one of the record signal files, e.g., Save PMT signals?, is selected ASCII 

text files containing time, U- and V-component signals are stored for all particles in the 

same directory as the original INI file. During instrument development and verification 

activities these signal files are used to drive an arbitrary waveform generator to provide 

realistic electronic signals to the laser velocimeter data acquisition system that are 

subsequently used to validate signal/data processing procedures. Again, since the answers 

are known, the actual instrument precision was determined for the hardware/software 

system used for the upgraded laser velocimeter. The results indicated that the hardware 

performed exactly as predicted by the simulation, with negligible, if any, electronic noise. 

Even the captured signals from the PXI high-speed digitizer overlaid exactly on the 

simulated signal used to drive the waveform generator.

Appendix A.24
 0.5145 Laser wavelength - U component, microns

 0.4880 Laser wavelength - V component, microns

 1.0000 Laser power - U component, W

 1.0000 Laser power - V component, W

 40.0000 Bragg frequency - U component, MHz

 40.0000 Bragg frequency - V component, MHz

 -0.1294 U-component beam 1 X location, m

 0.0000 U-component beam 1 Y location, m

 0.1294 U-component beam 2 X location, m

 0.0000 U-component beam 2 Y location, m

 0.0000 V-component beam 1 X location, m

 -0.1294 V-component beam 1 Y location, m

 0.0000 V-component beam 2 X location, m

 0.1294 V-component beam 2 Y location, m

 0.3056 Transmission U-component Beam 1

 0.2800 Transmission U-component Beam 2

 0.3056 Transmission V-component Beam 1

 0.2800 Transmission V-component Beam 2

 84.0000 Polarization angle U-comp Beam 1, deg

 89.0000 Polarization angle U-comp Beam 2, deg

 0.0000 Polarization angle V-comp Beam 1, deg

 0.0000 Polarization angle V-comp Beam 2, deg

 0.0175 Effective diameter of laser beam, m

 4.8770 Transmitter focal distance, m

 4.8770 Receiver focal distance, m

 0.0000 Vertical angle of receiver, deg

 180.0000 Horizontal angle of receiver, deg

 0.2750 Effective diameter of receiver, m

 0.6500 Transmission U-component Rec

 0.6500 Transmission V-component Rec

 0.1500 PMT quantum efficiency

 1.0000 PMT gain, M

 10.0000 System gain, dB

 2.0000 High Pass filter break U-comp, MHz

 100.0000 Low Pass filter break U-comp, MHz

 2.0000 High Pass filter break V-comp, MHz

 100.0000 Low Pass filter break V-comp, MHz

 1000.0 Digitizing sample rate, MHz

 1.5900 Particle index of refraction Real

 0.0000 Particle index of refraction Img

 X Single particle size

 Uniform particle size distribution

 1/r3 particle size distribution

 Gaussian particle size distribution

 1.7000 Starting/Single particle size, microns

 0.0000 Ending particle size, microns

 1000 Particle data rate, #/sec

 10000 Maximum number of particles

 100.0000 Mean velocity, input, m/s

 3.0000 Velocity standard deviation, input, m/s

 0.0000 Mean vertical flow angle, input, deg

 4.0000 Flow angle standard deviation, input, deg

Table A-1.- Input parameters for the Monte Carlo simulation program that include the characteristics of the 

upgraded laser velocimeter optical system, electronics settings, seeding particle characteristics, and flow 

characteristics.

Appendix A.25
 0.0000 Mean horizontal flow angle, input, deg

 0.0000 Flow angle standard deviation, input, deg

 0.0500 Signal threshold to trigger capture

 X Trigger at center of burst?

 1.0000 +/- Full Scale A/D voltage (1,2,5,10...)

 n Downmix LV signal?

 0.0000 U-Reference Frequency for Double-Balanced Mixer, MHz

 0.0000 V-Reference Frequency for Double-Balanced Mixer, MHz

 y Save all Histogram Plots?

 n Set all plots to 15 sec view?

 Save PMT signals?

 Save High-Pass Filtered Signals?

 Save Triggered Signals?

 Save A/D Captured Signals?

Particle Size: 1.7

 U-component

 Pedestal Beam A: 0.080

 Pedestal Beam B: 0.079

 Average Signal Level: 0.155

 Average Phase Angle: -179.959

 V-component

 Pedestal Beam A: 0.399

 Pedestal Beam B: 0.421

 Average Signal Level: 0.818

 Average Phase Angle: -0.063

Table A-1 (cont'd).- Input parameters for the Monte Carlo simulation program that include the characteristics of 

the upgraded laser velocimeter optical system, electronics settings, seeding particle characteristics, and flow 

characteristics.

Appendix A.26
Table A-2.- The input, measured and error characteristics of every particle that was generated in the Monte Carlo 

simulation.

Appendix A.27

Particle Size Vel-mag Alpha Beta X-start X-end Y-start Y-end Z-start Z-end U-in V-in U-select V-select U-m eas V-meas Error U Error V

 1 1.70 102.56 7.56 0.00 -1.50 1.50 -1.486 -1.088 -1.473 -1.473 101.671 13.497  2 1.70 99.11 4.99 0.00 -1.50 1.50 0.340 0.602 1.448 1.448 98.729 8.627 98.73 8.63

 3 1.70 98.85 -8.73 0.00 -1.50 1.50 -1.324 -1.785 -1.281 -1.281 97.707 -15.004  4 1.70 100.64 3.53 0.00 -1.50 1.50 0.581 0.766 -0.234 -0.234 100.450 6.195 100.45 6.19 100.13 6.13 -0.32 -0.06 5 1.70 101.86 -7.00 0.00 -1.50 1.50 -0.510 -0.878 -0.310 -0.310 101.097 -12.415 101.10 -12.41 101.42 -12.60 0.32 -0.18 6 1.70 94.92 -1.03 0.00 -1.50 1.50 -1.199 -1.254 0.968 0.968 94.903 -1.711  7 1.70 98.77 -0.59 0.00 -1.50 1.50 0.884 0.853 1.246 1.246 98.767 -1.010  8 1.70 101.54 4.34 0.00 -1.50 1.50 -0.429 -0.201 -0.062 -0.062 101.246 7.686 101.25 7.69 101.31 7.83 0.06 0.15 9 1.70 99.75 -4.44 0.00 -1.50 1.50 -0.855 -1.088 -0.155 -0.155 99.455 -7.721 99.46 -7.72 99.44 -7.44 -0.02 0.28 10 1.70 101.77 -3.71 0.00 -1.50 1.50 0.473 0.279 -1.369 -1.369 101.554 -6.577 101.55 -6.58 11 1.70 103.93 -1.48 0.00 -1.50 1.50 0.262 0.185 -0.665 -0.665 103.893 -2.683 103.89 -2.68 104.37 -2.73 0.48 -0.04 12 1.70 101.14 5.32 0.00 -1.50 1.50 -0.815 -0.536 0.352 0.352 100.703 9.375 100.70 9.37 100.21 9.45 -0.49 0.07 13 1.70 102.09 -3.46 0.00 -1.50 1.50 -1.075 -1.256 1.102 1.102 101.904 -6.157  14 1.70 101.87 -5.06 0.00 -1.50 1.50 -0.657 -0.923 -0.682 -0.682 101.471 -8.986 101.47 -8.99 102.28 -8.80 0.81 0.19 15 1.70 100.43 1.82 0.00 -1.50 1.50 -0.741 -0.646 1.104 1.104 100.382 3.182  16 1.70 97.95 -6.90 0.00 -1.50 1.50 -1.384 -1.748 1.019 1.019 97.236 -11.771  17 1.70 100.15 -7.07 0.00 -1.50 1.50 -0.426 -0.798 -1.100 -1.100 99.385 -12.329 99.39 -12.33 100.16 -12.51 0.78 -0.18 18 1.70 98.40 -1.26 0.00 -1.50 1.50 -0.040 -0.106 0.435 0.435 98.377 -2.171 98.38 -2.17 98.40 -2.12 0.02 0.05 19 1.70 101.54 -0.30 0.00 -1.50 1.50 -0.794 -0.810 -0.172 -0.172 101.542 -0.530 101.54 -0.53 101.43 -0.28 -0.11 0.25 20 1.70 96.08 -4.37 0.00 -1.50 1.50 0.482 0.253 0.458 0.458 95.801 -7.318 95.80 -7.32 96.14 -7.35 0.34 -0.03 21 1.70 102.84 -1.59 0.00 -1.50 1.50 -0.536 -0.619 0.768 0.768 102.798 -2.853 102.80 -2.85 102.53 -2.57 -0.27 0.29 22 1.70 99.06 2.93 0.00 -1.50 1.50 0.320 0.473 0.629 0.629 98.934 5.057 98.93 5.06 99.22 5.08 0.29 0.02 23 1.70 104.92 -0.50 0.00 -1.50 1.50 -1.057 -1.084 -1.220 -1.220 104.918 -0.922  24 1.70 101.83 -3.22 0.00 -1.50 1.50 1.119 0.950 0.493 0.493 101.667 -5.717 101.67 -5.72 101.74 -5.09 0.07 0.63 25 1.70 98.66 -3.19 0.00 -1.50 1.50 -0.673 -0.840 -0.058 -0.058 98.512 -5.487 98.51 -5.49 98.77 -5.42 0.26 0.07 26 1.70 96.13 1.99 0.00 -1.50 1.50 -0.326 -0.221 1.378 1.378 96.074 3.345 96.07 3.34 27 1.70 95.78 2.19 0.00 -1.50 1.50 -0.659 -0.544 -0.081 -0.081 95.711 3.662 95.71 3.66 96.13 3.78 0.42 0.11 28 1.70 100.14 -6.13 0.00 -1.50 1.50 0.141 -0.181 0.076 0.076 99.570 -10.696 99.57 -10.70 99.64 -10.67 0.07 0.03 29 1.70 103.81 -1.55 0.00 -1.50 1.50 1.286 1.205 0.066 0.066 103.769 -2.805  30 1.70 96.37 -1.72 0.00 -1.50 1.50 0.309 0.219 -1.293 -1.293 96.327 -2.890 96.33 -2.89 95.42 -2.51 -0.91 0.38 31 1.70 99.35 6.01 0.00 -1.50 1.50 -0.451 -0.136 -0.775 -0.775 98.806 10.396 98.81 10.40 98.96 10.34 0.15 -0.06 32 1.70 100.62 -0.77 0.00 -1.50 1.50 0.948 0.908 1.004 1.004 100.615 -1.348  33 1.70 98.98 7.04 0.00 -1.50 1.50 -0.622 -0.252 -0.279 -0.279 98.232 12.127 98.23 12.13 98.16 12.04 -0.07 -0.09 34 1.70 101.02 0.11 0.00 -1.50 1.50 0.943 0.948 -0.135 -0.135 101.021 0.187 101.02 0.19 101.39 0.41 0.36 0.22 35 1.70 100.17 -0.43 0.00 -1.50 1.50 -0.122 -0.144 0.930 0.930 100.166 -0.756 100.17 -0.76 99.87 -0.99 -0.30 -0.24 36 1.70 99.15 5.62 0.00 -1.50 1.50 -0.904 -0.608 -0.709 -0.709 98.675 9.712 98.68 9.71 98.92 9.95 0.25 0.24 37 1.70 102.34 0.88 0.00 -1.50 1.50 -0.355 -0.309 -0.545 -0.545 102.333 1.579 102.33 1.58 102.65 1.33 0.32 -0.25 38 1.70 101.43 5.08 0.00 -1.50 1.50 0.326 0.593 -0.941 -0.941 101.030 8.979 101.03 8.98 102.29 9.08 1.26 0.10 39 1.70 100.78 1.45 0.00 -1.50 1.50 -0.847 -0.771 0.089 0.089 100.745 2.555 100.74 2.55 100.73 2.67 -0.02 0.12 40 1.70 98.92 3.65 0.00 -1.50 1.50 -0.665 -0.474 1.484 1.484 98.716 6.299 98.72 6.30 41 1.70 96.93 -4.69 0.00 -1.50 1.50 0.717 0.471 -0.328 -0.328 96.610 -7.924 96.61 -7.92 96.49 -8.10 -0.12 -0.18 42 1.70 98.13 -0.35 0.00 -1.50 1.50 -1.430 -1.449 1.289 1.289 98.131 -0.596  43 1.70 107.01 1.83 0.00 -1.50 1.50 0.399 0.495 1.398 1.398 106.955 3.420 106.95 3.42 44 1.70 100.67 5.03 0.00 -1.50 1.50 0.518 0.782 0.562 0.562 100.286 8.824 100.29 8.82 99.67 9.06 -0.61 0.24 45 1.70 97.42 -0.81 0.00 -1.50 1.50 1.456 1.414 -0.654 -0.654 97.406 -1.372  46 1.70 103.20 -3.79 0.00 -1.50 1.50 -1.047 -1.246 -0.131 -0.131 102.974 -6.820  47 1.70 99.47 -3.99 0.00 -1.50 1.50 0.631 0.422 0.474 0.474 99.228 -6.930 99.23 -6.93 99.63 -7.03 0.40 -0.10 48 1.70 95.94 0.95 0.00 -1.50 1.50 0.591 0.641 1.255 1.255 95.926 1.595  49 1.70 102.79 0.65 0.00 -1.50 1.50 -0.830 -0.796 0.748 0.748 102.785 1.159 102.78 1.16 102.79 0.69 0.01 -0.47
Input particle velocity statistics

Velocity Magnitude: 100.01 Standard Deviation: 2.97

Alpha: 0.01 Standard Deviation: 4.01

Beta: 0.00 Standard Deviation: 0.00

U-component 99.77 Standard Deviation: 2.97

V-component 0.02 Standard Deviation: 6.99

 Number of measurements: 10000.

Selected particle velocity statistics

Velocity Magnitude: 99.98 Standard Deviation: 2.97

Alpha: 0.03 Standard Deviation: 4.01

U-component 99.74 Standard Deviation: 2.98

V-component 0.05 Standard Deviation: 7.05

 Number of measurements: 5707.

Measured particle velocity statistics

Velocity Magnitude: 101.07 Standard Deviation: 14.00

Alpha: -0.01 Standard Deviation: 14.37

U-component 97.54 Standard Deviation: 28.89

V-component 0.04 Standard Deviation: 7.86

 Number of measurements: 4973.

Measurement Errors

Velocity Magnitude: 1.09 Standard Deviation: 13.60

Alpha: -0.04 Standard Deviation: 13.57

U-component -2.19 Standard Deviation: 28.82

V-component -0.02 Standard Deviation: 3.60

Table A-3.- Input particle statistics, statistics for particles that triggered the data acquisition system, statistics for 

particles that were measured along with the statistics for the particle-by-particle errors (instrument precision) 

based on a flow with a velocity magnitude of 100.0 m/s with a standard deviation of 3.0 m/s, and a mean flow 

angle of 0.0 degrees with a standard deviation of 4.0 degrees.

Measured particle velocity statistics

 Outliers Removed

Velocity Magnitude: 100.02 Standard Deviation: 3.00

Alpha: 0.05 Standard Deviation: 4.02

U-component 99.78 Standard Deviation: 3.01

V-component 0.09 Standard Deviation: 7.00

 Number of measurements: 4943.

Measurement Errors

Velocity Magnitude: 0.05 Standard Deviation: 0.39

Alpha: 0.01 Standard Deviation: 0.13

U-component 0.05 Standard Deviation: 0.39

V-component 0.03 Standard Deviation: 0.22

Table A-4.- Statistics for particles that were measured, outliers removed, along with the statistics for the particleby-particle errors (final instrument precision) based on a flow with a velocity magnitude of 100.0 m/s with a 

standard deviation of 3.0 m/s, and a mean flow angle of 0.0 degrees with a standard deviation of 4.0 degrees.

Appendix A.28
Table A-5.- Input, measured and error characteristics of each particle that had a signal burst level sufficient to 

trigger the data acquisition system, and was not rejected as an outlier. These particle characteristics were used 

to calculate the statistical quantities that characterized the flow.

Appendix A.29

Particle Size Vel-mag Alpha Mag-meas Alpha-meas Error-Mag Error-Alpha U-select V-select U-meas V-meas Error U Error V 4 1.70 100.641 3.529 100.316 3.504 -0.325 -0.025 100.450 6.195 100.129 6.130 -0.322 -0.065

 5 1.70 101.857 -7.001 102.198 -7.081 0.341 -0.081 101.097 -12.415 101.418 -12.599 0.321 -0.184

 8 1.70 101.538 4.341 101.611 4.422 0.074 0.081 101.246 7.686 101.309 7.835 0.062 0.149

 9 1.70 99.754 -4.439 99.716 -4.281 -0.038 0.158 99.455 -7.721 99.438 -7.443 -0.017 0.278

 11 1.70 103.928 -1.480 104.405 -1.497 0.478 -0.017 103.893 -2.683 104.370 -2.727 0.477 -0.043

 12 1.70 101.138 5.319 100.654 5.386 -0.484 0.067 100.703 9.375 100.210 9.448 -0.493 0.073

 14 1.70 101.868 -5.061 102.662 -4.915 0.794 0.146 101.471 -8.986 102.285 -8.795 0.813 0.191

 17 1.70 100.147 -7.072 100.941 -7.117 0.794 -0.045 99.385 -12.329 100.163 -12.506 0.778 -0.177

 18 1.70 98.401 -1.264 98.418 -1.237 0.017 0.027 98.377 -2.171 98.395 -2.125 0.018 0.046

 19 1.70 101.543 -0.299 101.427 -0.160 -0.116 0.139 101.542 -0.530 101.427 -0.283 -0.115 0.246

 20 1.70 96.080 -4.368 96.424 -4.372 0.344 -0.004 95.801 -7.318 96.143 -7.351 0.342 -0.032

 21 1.70 102.838 -1.590 102.558 -1.433 -0.280 0.156 102.798 -2.853 102.526 -2.566 -0.272 0.288

 22 1.70 99.063 2.926 99.353 2.931 0.289 0.005 98.934 5.057 99.223 5.081 0.288 0.024

 24 1.70 101.828 -3.218 101.865 -2.863 0.038 0.355 101.667 -5.717 101.738 -5.089 0.071 0.628

 25 1.70 98.665 -3.188 98.918 -3.140 0.254 0.048 98.512 -5.487 98.770 -5.418 0.258 0.069

 27 1.70 95.781 2.191 96.209 2.249 0.428 0.059 95.711 3.662 96.135 3.776 0.424 0.115

 28 1.70 100.143 -6.131 100.211 -6.112 0.069 0.019 99.570 -10.696 99.642 -10.670 0.072 0.026

 30 1.70 96.371 -1.719 95.448 -1.505 -0.923 0.213 96.327 -2.890 95.415 -2.507 -0.912 0.383

 31 1.70 99.351 6.007 99.497 5.966 0.146 -0.041 98.806 10.396 98.959 10.341 0.153 -0.055

 33 1.70 98.977 7.038 98.895 6.991 -0.083 -0.047 98.232 12.127 98.159 12.037 -0.072 -0.090

 34 1.70 101.021 0.106 101.386 0.232 0.365 0.126 101.021 0.187 101.385 0.410 0.364 0.223

 35 1.70 100.169 -0.432 99.871 -0.569 -0.299 -0.137 100.166 -0.756 99.866 -0.993 -0.301 -0.237

 36 1.70 99.152 5.621 99.423 5.745 0.271 0.124 98.675 9.712 98.924 9.952 0.249 0.240

 37 1.70 102.345 0.884 102.661 0.741 0.316 -0.143 102.333 1.579 102.653 1.328 0.320 -0.251

 38 1.70 101.428 5.079 102.696 5.070 1.268 -0.009 101.030 8.979 102.294 9.075 1.264 0.096

 39 1.70 100.777 1.453 100.764 1.520 -0.013 0.067 100.745 2.555 100.728 2.673 -0.016 0.118

 41 1.70 96.934 -4.689 96.825 -4.800 -0.110 -0.111 96.610 -7.924 96.485 -8.101 -0.125 -0.177

 44 1.70 100.674 5.029 100.084 5.195 -0.590 0.167 100.286 8.824 99.673 9.063 -0.613 0.238

 47 1.70 99.470 -3.995 99.876 -4.037 0.407 -0.042 99.228 -6.930 99.629 -7.031 0.401 -0.101

 49 1.70 102.791 0.646 102.795 0.387 0.004 -0.259 102.785 1.159 102.793 0.694 0.008 -0.465

 50 1.70 109.355 5.880 109.663 5.813 0.308 -0.067 108.780 11.202 109.099 11.107 0.319 -0.095

 51 1.70 98.570 -0.867 98.744 -0.872 0.175 -0.005 98.558 -1.491 98.733 -1.502 0.175 -0.011

 53 1.70 103.048 -5.508 103.560 -5.446 0.512 0.062 102.572 -9.892 103.093 -9.828 0.520 0.063

 55 1.70 97.654 -1.185 97.593 -0.984 -0.061 0.201 97.633 -2.019 97.578 -1.675 -0.055 0.344

 59 1.70 96.339 -0.060 96.602 0.125 0.263 0.185 96.339 -0.101 96.602 0.211 0.263 0.312

 61 1.70 100.564 6.086 101.051 6.046 0.487 -0.040 99.998 10.662 100.489 10.644 0.491 -0.018

 66 1.70 100.613 0.022 100.195 0.317 -0.419 0.296 100.613 0.038 100.193 0.555 -0.420 0.517

 71 1.70 97.334 -1.031 97.121 -1.099 -0.213 -0.068 97.318 -1.752 97.103 -1.863 -0.215 -0.112

 72 1.70 101.552 -7.365 101.532 -7.579 -0.020 -0.214 100.714 -13.018 100.645 -13.391 -0.069 -0.373

 73 1.70 101.639 -7.759 101.491 -7.852 -0.148 -0.093 100.709 -13.722 100.539 -13.865 -0.169 -0.143

 77 1.70 98.721 1.360 98.957 1.399 0.236 0.038 98.693 2.344 98.927 2.416 0.234 0.072

 79 1.70 96.089 -1.298 96.256 -1.226 0.166 0.072 96.064 -2.177 96.233 -2.060 0.169 0.117

 81 1.70 100.802 0.416 100.879 0.570 0.077 0.155 100.800 0.731 100.874 1.004 0.074 0.273

 82 1.70 99.330 2.969 99.404 2.993 0.073 0.023 99.197 5.145 99.268 5.190 0.071 0.044

 86 1.70 102.298 0.725 102.387 0.605 0.089 -0.120 102.290 1.295 102.381 1.081 0.091 -0.214

 87 1.70 99.973 1.125 100.301 1.054 0.328 -0.071 99.954 1.962 100.284 1.845 0.330 -0.117

 88 1.70 99.301 1.268 98.888 1.388 -0.413 0.121 99.277 2.197 98.859 2.396 -0.418 0.199

 91 1.70 96.181 -3.003 96.129 -2.946 -0.052 0.057 96.049 -5.040 96.002 -4.941 -0.047 0.099

 92 1.70 102.047 3.173 102.341 3.047 0.295 -0.127 101.890 5.649 102.197 5.440 0.307 -0.209
Figure A.1.- Captured signal bursts from particles passing through the center and edge of a laser velocimeter 

measurement volume.

Figure A.2.- Simulated signal bursts from particles passing through the center and edge of a laser velocimeter 

measurement volume.

Appendix A.30

Amplitude

Time

Amplitude, V

0.8

0.6

0.4

0.2

0

0 0.5

Time, sec μ

1.0

Amplitude, V 0.25

0.20

0.15

0.10

0.05

0

0 0.5

Time, sec μ

1.0
Figure A.3.- Opening data entry screen for the Monte Carlo simulation of a two-component, fringe-type laser 

velocimeter.

Appendix A.31

LV Sim INI file:New INI file?

Next Exit

n

J:\LVsim2008Flow32\FFTtestNASA.ini

Laser Velocimeter Simulation
Figure A.4.- Data entry screen for the characteristics of the transmission optics for a two-component, fringe-type 

laser velocimeter.

Appendix A.32

LV Simulation - Transmitter

U-component V-component

Laser Wavelength, m: μLaser Power, W:

Bragg Frequency, MHz:

Beam 1 Location (X,Y), m:

Beam 2 Location (X,Y), m:

Transmission (Beam 1,2):

Polarization (Beam 1,2):

Laser Beam Diameter, m:

Focal Distance, m:

Next Exit

0.5145

1.00

40.00

-0.1294 0.0000

0.1294 0.0000

0.31 0.28

0.00 89.00

0.0175

4.877

-0.1294

0.1294

0.31

84.00

0.0000

0.0000

0.28

0.00

0.4880

1.00

40.00
Figure A.5.- Data entry screen for the characteristics of the receiver optics for a two-component, fringe-type laser 

velocimeter.

Appendix A.33

LV Simulation - Receiver

Focal Distance, m:

Alpha View, deg:

Theta View, deg:

Effective Lens Diameter, m:

Transmission:

PMT Quantum Efficiency:

PMT Gain, M:

System Gain, dB:

High Pass Filter, MHZ:

Low Pass Filter, MHZ:

Sample Rate, MHz

(0 -> Auto)

V-component U-componentV-component U-component

Next Exit

4.877

0.0000

180.000

0.275

1000.0

0.65 0.65

0.15

1.000

10.00

2.0

100.0 100.0

2.0
Figure A.6.- Data entry screen for the characteristics of the seeding particles and the flow field along with plotting 

and storage parameters for the Monte Carlo simulation of a two-component, fringe-type laser velocimeter.

Appendix A.34

LV Simulation - Particles and Flow

Save PMT Signals?Save High-Pass Signals?

Save Triggered Signals?

Save A/D Captures?

Single Size:

Uniform Distribution:

1/r3 Distribution:Gaussian Distribution:

Number of Particles:

Std Deviation, m/s:

Std Deviation, deg:

Std Deviation, deg:

Trigger Mid Burst?:

Downmix Signal?:

U-Downmix Freq, MHz:

V-Downmix Freq, MHz:

Refractive Index - Real:

Refractive Index - Img:

Start/Single Size:

End Particle Size:Data Rate, #/sec:

Mean Beta, deg:Signal Threshold, V:

Mean Velocity, m/s:

Mean Alpha, deg:

Full Scale A/D, V:

Save Histogram Plots?Auto Display Plots?

10000

Run Exit

yn

0.05

1.00

0.00.0

1000

100.0

1.7

1.59

0.00

X

3.04.00.0

X

n
Figure A.7.a.- Mie scattering maps of pedestal amplitude for both laser beams, Doppler signal amplitude, and 

phase angle for the U-component and a 0.5-micron particle.

Appendix A.35

 2.7 2.8

Particle size = 0.5 microns

U-component, Pedestal Beam A

 2.7 2.8

Particle size = 0.5 microns

U-component, Pedestal Beam B

 0.0 5.6

Particle size = 0.5 microns

U-component, Doppler

 -3.1 3.1

Particle size = 0.5 microns

U-component, Phase
Figure A.7.b.- Mie scattering maps of pedestal amplitude for both laser beams, Doppler signal amplitude, and 

phase angle for the V-component and a 0.5-micron particle.

Appendix A.36

 3.8 3.9

Particle size = 0.5 microns

V-component, Pedestal Beam A

 3.8 3.9

Particle size = 0.5 microns

V-component, Pedestal Beam B

 7.7 7.8

Particle size = 0.5 microns

V-component, Doppler

 0.0 0.0

Particle size = 0.5 microns

V-component, Phase
Figure A.7.c.- Mie scattering maps of optical power and signal levels for the U- and V-components from a 

0.5-micron particle.

Appendix A.37

 0.0 5.6

Particle size = 0.5 microns

U-component, Power

 0.0 5.6

Particle size = 0.5 microns

U-component, Signal

 7.7 7.8

Particle size = 0.5 microns

V-component, Power

 7.7 7.8

Particle size = 0.5 microns

V-component, Signal
Figure A.7.d.- High-pass filtered U- and V-component signals in the time and frequency domains.

Appendix A.38

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16 Particle size = 0.5 microns

U-component, Photomultiplier signal

Signal level, V

Time, microsec

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

0.10 Particle size = 0.5 microns

U-component, High-pass filtered signal

Signal level, V

Time, microsec

0 40 80 120 160 200

0

2

4

6

8

10 Particle size = 0.5 microns

U-component, High-pass filtered signal

Power, V2

Frequency, MHz

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

0.00

0.02

0.04

0.06

0.08 Particle size = 0.5 microns

V-component, Photomultiplier signal

Signal level, V

Time, microsec

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-0.02

-0.01

0.00

0.01

0.02

0.03

0.04 Particle size = 0.5 microns

V-component, High-pass filtered signal

Signal level, V

Time, microsec

0 40 80 120 160 200

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Power, V2

Frequency, MHz

Particle size = 0.5 microns

V-component, High-pass filtered signal
Figure A.8.a.- Mie scattering maps of pedestal amplitude for both laser beams, Doppler signal amplitude, and 

phase angle for the U-component and a 1.0-micron particle.

Appendix A.39

 51.3 55.1

Particle size = 1.0 microns

U-component, Pedestal Beam A

 51.3 55.1

Particle size = 1.0 microns

U-component, Pedestal Beam B

 0.1 108.4

Particle size = 1.0 microns

U-component, Doppler

 -3.1 3.1

Particle size = 1.0 microns

U-component, Phase
Figure A.8.b.- Mie scattering maps of pedestal amplitude for both laser beams, Doppler signal amplitude, and 

phase angle for the V-component and a 1.0-micron particle.

Appendix A.40

 74.0 80.2

Particle size = 1.0 microns

V-component, Pedestal Beam A

 74.0 80.2

Particle size = 1.0 microns

V-component, Pedestal Beam B

 154.0 157.4

Particle size = 1.0 microns

V-component, Doppler

 0.0 0.0

Particle size = 1.0 microns

V-component, Phase
Figure A.8.c.- Mie scattering maps of optical power and signal levels for the U- and V-components from a 

1.0-micron particle.

Appendix A.41

 0.0 108.4

Particle size = 1.0 microns

U-component, Power

 0.0 108.4

Particle size = 1.0 microns

U-component, Signal

 153.9 157.4

Particle size = 1.0 microns

V-component, Power

 154.0 157.4

Particle size = 1.0 microns

V-component, Signal
Figure A.8.d.- High-pass filtered U- and V-component signals in the time and frequency domains.

Appendix A.42

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6 Particle size = 1.0 micron

U-component, Photomultiplier signal

Signal level, V

Time, microsec

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8 Particle size = 1.0 micron

U-component, High-pass filtered signal

Signal level, V

Time, microsec

0 40 80 120 160 200

0

50

100

150

200 Particle size = 1.0 micron

U-component, High-pass filtered signal

Power, V2

Frequency, MHz

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

0.0

0.2

0.4

0.6

0.8

1.0 Particle size = 1.0 micron

V-component, Photomultiplier signal

Signal level, V

Time, microsec

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6 Particle size = 1.0 micron

V-component, High-pass filtered signal

Signal level, V

Time, microsec

0 40 80 120 160 200

0

20

40

60

80

100

120

140

160

Power, V2

Frequency, MHz

Particle size = 1.0 micron

V-component, High-pass filtered signal
Figure A.9.a.- Mie scattering maps of pedestal amplitude for both laser beams, Doppler signal amplitude, and 

phase angle for the U-component and a 1.7-micron particle.

Appendix A.43

 53.3 66.1

Particle size = 1.7 microns

U-component, Pedestal Beam A

 53.3 66.1

Particle size = 1.7 microns

U-component, Pedestal Beam B

 0.2 125.9

Particle size = 1.7 microns

U-component, Doppler

 -3.1 3.1

Particle size = 1.7 microns

U-component, Phase
Figure A.9.b.- Mie scattering maps of pedestal amplitude for both laser beams, Doppler signal amplitude, and 

phase angle for the V-component and a 1.7-micron particle.

Appendix A.44

 285.0 343.5

Particle size = 1.7 microns

V-component, Pedestal Beam A

 284.9 343.5

Particle size = 1.7 microns

V-component, Pedestal Beam B

 619.4 657.9

Particle size = 1.7 microns

V-component, Doppler

 0.0 0.0

Particle size = 1.7 microns

V-component, Phase
Figure A.9.c.- Mie scattering maps of optical power and signal levels for the U- and V-components from a 

1.7-micron particle.

Appendix A.45

 0.0 125.9

Particle size = 1.7 microns

U-component, Power

 0.0 125.9

Particle size = 1.7 microns

U-component, Signal

 618.7 657.9

Particle size = 1.7 microns

V-component, Power

 619.4 657.9

Particle size = 1.7 microns

V-component, Signal
Figure A.9.d.- High-pass filtered U- and V-component signals in the time and frequency domains.

Appendix A.46

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6 Particle size = 1.7 microns

U-component, Photomultiplier signal

Signal level, V

Time, microsec

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8 Particle size = 1.7 microns

U-component, High-pass filtered signal

Signal level, V

Time, microsec

0 40 80 120 160 200

0

20

40

60

80

100

120

140

160

180

200 Particle size = 1.7 microns

U-component, High-pass filtered signal

Power, V2

Frequency, MHz

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

0

1

2

3

4 Particle size = 1.7 microns

V-component, Photomultiplier signal

Signal level, V

Time, microsec

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0 Particle size = 1.7 microns

V-component, High-pass filtered signal

Signal level, V

Time, microsec

0 40 80 120 160 200

0

100

200

300

400

500

600

Power, V2

Frequency, MHz

Particle size = 1.7 microns

V-component, High-pass filtered signal
Figure A.10.a.- Mie scattering maps of pedestal amplitude for both laser beams, Doppler signal amplitude, and 

phase angle for the U-component and a 2.0-micron particle.

Appendix A.47

 176.9 236.7

Particle size = 2.0 microns

U-component, Pedestal Beam A

 176.8 236.8

Particle size = 2.0 microns

U-component, Pedestal Beam B

 0.2 442.8

Particle size = 2.0 microns

U-component, Doppler

 -3.1 3.1

Particle size = 2.0 microns

U-component, Phase
Figure A.10.b.- Mie scattering maps of pedestal amplitude for both laser beams, Doppler signal amplitude, and 

phase angle for the V-component and a 2.0-micron particle.

Appendix A.48

 199.8 269.4

Particle size = 2.0 microns

V-component, Pedestal Beam A

 199.7 269.4

Particle size = 2.0 microns

V-component, Pedestal Beam B

 463.8 503.0

Particle size = 2.0 microns

V-component, Doppler

 0.0 0.0

Particle size = 2.0 microns

V-component, Phase
Figure A.10.c.- Mie scattering maps of optical power and signal levels for the U- and V-components from a 

2.0-micron particle.

Appendix A.49

 0.0 442.8

Particle size = 2.0 microns

U-component, Power

 0.2 442.8

Particle size = 2.0 microns

U-component, Signal

 458.7 503.0

Particle size = 2.0 microns

V-component, Power

 463.3 503.0

Particle size = 2.0 microns

V-component, Signal
Figure A.10.d.- High-pass filtered U- and V-component signals in the time and frequency domains.

Appendix A.50

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

0

1

2

3

4

5

6 Particle size = 2.0 microns

U-component, Photomultiplier signal

Signal level, V

Time, microsec

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-3

-2

-1

0

1

2

3 Particle size = 2.0 microns

U-component, High-pass filtered signal

Signal level, V

Time, microsec

0 40 80 120 160 200

0

100

200

300

400

500

600

700

800

900 Particle size = 2.0 microns

U-component, High-pass filtered signal

Power, V2

Frequency, MHz

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5 Particle size = 2.0 microns

V-component, Photomultiplier signal

Signal level, V

Time, microsec

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6 Particle size = 2.0 microns

V-component, High-pass filtered signal

Signal level, V

Time, microsec

0 40 80 120 160 200

0

100

200

300

400

500

Power, V2

Frequency, MHz

Particle size = 2.0 microns

V-component, High-pass filtered signal
Figure A.11.a.- Mie scattering maps of pedestal amplitude for both laser beams, Doppler signal amplitude, and 

phase angle for the U-component and a 3.0-micron particle.

Appendix A.51

 271.5 626.7

Particle size = 3.0 microns

U-component, Pedestal Beam A

 271.2 626.7

Particle size = 3.0 microns

U-component, Pedestal Beam B

 2.0 1049.8

Particle size = 3.0 microns

U-component, Doppler

 -3.1 3.1

Particle size = 3.0 microns

U-component, Phase
Figure A.11.b.- Mie scattering maps of pedestal amplitude for both laser beams, Doppler signal amplitude, and 

phase angle for the V-component and a 3.0-micron particle.

Appendix A.52

 35.2 149.5

Particle size = 3.0 microns

V-component, Pedestal Beam A

 35.1 149.5

Particle size = 3.0 microns

V-component, Pedestal Beam B

 143.2 233.5

Particle size = 3.0 microns

V-component, Doppler

 -0.3 0.3

Particle size = 3.0 microns

V-component, Phase
Figure A.11.c.- Mie scattering maps of optical power and signal levels for the U- and V-components from a 

3.0-micron particle.

Appendix A.53

 0.0 1049.8

Particle size = 3.0 microns

U-component, Power

 0.0 1049.8

Particle size = 3.0 microns

U-component, Signal

 113.1 220.8

Particle size = 3.0 microns

V-component, Power

 137.0 233.5

Particle size = 3.0 microns

V-component, Signal
Figure A.11.d.- High-pass filtered U- and V-component signals in the time and frequency domains.

Appendix A.54

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

0

1

2

3

4

5

6

7

8

9

10

11

12 Particle size = 3.0 microns

U-component, Photomultiplier signal

Signal level, V

Time, microsec

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6 Particle size = 3.0 microns

U-component, High-pass filtered signal

Signal level, V

Time, microsec

0 40 80 120 160 200

0

200

400

600

800

1000

1200

1400

1600

1800

2000 Particle size = 3.0 microns

U-component, High-pass filtered signal

Power, V2

Frequency, MHz

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6 Particle size = 3.0 microns

V-component, Photomultiplier signal

Signal level, V

Time, microsec

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6 Particle size = 3.0 microns

V-component, High-pass filtered signal

Signal level, V

Time, microsec

0 40 80 120 160 200

0

50

100

150

200

Power, V2

Frequency, MHz

Particle size = 3.0 microns

V-component, High-pass filtered signal
Figure A.12.- Photomultiplier output from a single photon as captured on an analog oscilloscope with 50-ohm 

termination.

Appendix A.55

Amplitude, mV

5

4

3

2

1

0

-1

-2

0 5 10 15 20 25

Time, nsec
Error U: 0.14 m/s, no measurement Error V: 0.0 m/s, no measurement

Figure A.13.- Signals obtained at on-axis = -0.75 Lmv, Histogram 5, True Half Power processing.

Appendix A.56

-1.0 -0.5 0.0 0.5 1.0

0

20

40

60

80

100

120

140

160

Signal level, nW

Time, microsec

Particle size = 1.7 microns

U-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Signal level, V

Time, microsec

Particle size = 1.7 microns

U-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Signal level,V

Time, microsec

Particle size = 1.7 microns

U-component, High-pass filtered signal

0.0

0.2

0.4

0.6

0.8

-0.6

-0.4

Sign

-0.2

-1.0 -0.5 0.0 0.5 1.0

-0.8

Time, microsec

al level,V

Particle size = 1.7 microns

U-component, Digitized signal

-1.0 -0.5 0.0 0.5 1.0

0

100

200

300

400

500

600

700

800

Signal level, nW

Time, microsec

Particle size = 1.7 microns

V-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Signal level, V

Time, microsec

Particle size = 1.7 microns

V-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Signal level,V

Time, microsec

Particle size = 1.7 microns

V-component, High-pass filtered signal

0.0

0.5

1.0

1.5

2.0 Particle size = 1.7 microns

V-component, Digitized signal

al level,V

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

Sign

-0.5

Time, microsec
Error U: 0.07 m/s, 0.25 m/s Error V: 0.16 m/s, 0.22 m/s

Figure A.14.- Signals obtained at on-axis = -0.5 Lmv, Histogram 5, True Half Power processing.

Appendix A.57

-1.0 -0.5 0.0 0.5 1.0

0

20

40

60

80

100

120

140

160

Signal level, nW

Time, microsec

Particle size = 1.7 microns

U-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Signal level, V

Time, microsec

Particle size = 1.7 microns

U-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Signal level,V

Time, microsec

Particle size = 1.7 microns

U-component, High-pass filtered signal

0.0

0.2

0.4

0.6

0.8

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

Signal level,V

-0.2

Time, microsec

Particle size = 1.7 microns

U-component, Digitized signal

-1.0 -0.5 0.0 0.5 1.0

0

100

200

300

400

500

600

700

800

Signal level, nW

Time, microsec

Particle size = 1.7 microns

V-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Signal level, V

Time, microsec

Particle size = 1.7 microns

V-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Signal level,V

Time, microsec

Particle size = 1.7 microns

V-component, High-pass filtered signal

0.0

0.5

1.0

1.5

2.0

al level,V

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

Sign

-0.5

Time, microsec

Particle size = 1.7 microns

V-component, Digitized signal
Error U: 0.32 m/s, 0.05 m/s Error V: -0.07 m/s, 0.25 m/s

Figure A.15.- Signals obtained at on-axis = -0.25 Lmv, Histogram 5, True Half Power processing.

Appendix A.58

-1.0 -0.5 0.0 0.5 1.0

0

20

40

60

80

100

120

140

160

Signal level, nW

Time, microsec

Particle size = 1.7 microns

U-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Signal level, V

Time, microsec

Particle size = 1.7 microns

U-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Signal level,V

Time, microsec

Particle size = 1.7 microns

U-component, High-pass filtered signal

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Signal level,V

Time, microsec

Particle size = 1.7 microns

U-component, Digitized signal

-1.0 -0.5 0.0 0.5 1.0

0

100

200

300

400

500

600

700

800

Signal level, nW

Time, microsec

Particle size = 1.7 microns

V-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Signal level, V

Time, microsec

Particle size = 1.7 microns

V-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Signal level,V

Time, microsec

Particle size = 1.7 microns

V-component, High-pass filtered signal

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Signal level,V

Time, microsec

Particle size = 1.7 microns

V-component, Digitized signal
Error U: 0.11 m/s, -0.01 m/s Error V: -0.02 m/s, -0.05 m/s

Figure A.16.- Signals obtained at on-axis = 0.0, Histogram 5, True Half Power processing.

Appendix A.59

-1.0 -0.5 0.0 0.5 1.0

0

20

40

60

80

100

120

140

160

Signal level, nW

Time, microsec

Particle size = 1.7 microns

U-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Signal level, V

Time, microsec

Particle size = 1.7 microns

U-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Signal level,V

Time, microsec

Particle size = 1.7 microns

U-component, High-pass filtered signal

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Signal level,V

Time, microsec

Particle size = 1.7 microns

U-component, Digitized signal

-1.0 -0.5 0.0 0.5 1.0

0

100

200

300

400

500

600

700

800

Signal level, nW

Time, microsec

Particle size = 1.7 microns

V-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Signal level, V

Time, microsec

Particle size = 1.7 microns

V-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Signal level,V

Time, microsec

Particle size = 1.7 microns

V-component, High-pass filtered signal

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Signal level,V

Time, microsec

Particle size = 1.7 microns

V-component, Digitized signal
Error U: -0.11 m/s, -0.13 m/s Error V: 0.13 m/s, 0.19 m/s

Figure A.17.- Signals obtained at on-axis = 0.25 Lmv, Histogram 5, True Half Power processing.

Appendix A.60

-1.0 -0.5 0.0 0.5 1.0

0

20

40

60

80

100

120

140

160

Signal level, nW

Time, microsec

Particle size = 1.7 microns

U-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Signal level, V

Time, microsec

Particle size = 1.7 microns

U-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Signal level,V

Time, microsec

Particle size = 1.7 microns

U-component, High-pass filtered signal

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Signal level,V

Time, microsec

Particle size = 1.7 microns

U-component, Digitized signal

-1.0 -0.5 0.0 0.5 1.0

0

100

200

300

400

500

600

700

800

Signal level, nW

Time, microsec

Particle size = 1.7 microns

V-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Signal level, V

Time, microsec

Particle size = 1.7 microns

V-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Signal level,V

Time, microsec

Particle size = 1.7 microns

V-component, High-pass filtered signal

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Signal level,V

Time, microsec

Particle size = 1.7 microns

V-component, Digitized signal
Error U: 0.52 m/s, 0.05 m/s Error V: -0.02 m/s, -0.18 m/s

Figure A.18.- Signals obtained at on-axis = 0.5 Lmv, Histogram 5, True Half Power processing.

Appendix A.61

-1.0 -0.5 0.0 0.5 1.0

0

20

40

60

80

100

120

140

160

Signal level, nW

Time, microsec

Particle size = 1.7 microns

U-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Signal level, V

Time, microsec

Particle size = 1.7 microns

U-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Signal level,V

Time, microsec

Particle size = 1.7 microns

U-component, High-pass filtered signal

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Signal level,V

Time, microsec

Particle size = 1.7 microns

U-component, Digitized signal

-1.0 -0.5 0.0 0.5 1.0

0

100

200

300

400

500

600

700

800

Signal level, nW

Time, microsec

Particle size = 1.7 microns

V-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Signal level, V

Time, microsec

Particle size = 1.7 microns

V-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Signal level,V

Time, microsec

Particle size = 1.7 microns

V-component, High-pass filtered signal

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Signal level,V

Time, microsec

Particle size = 1.7 microns

V-component, Digitized signal
Error U: 0.01 m/s, no measurement Error V: 0.25 m/s, no measurement

Figure A.19.- Signals obtained at on-axis = 0.75 Lmv, Histogram 5, True Half Power processing.

Appendix A.62

-1.0 -0.5 0.0 0.5 1.0

0

20

40

60

80

100

120

140

160

Signal level, nW

Time, microsec

Particle size = 1.7 microns

U-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Signal level, V

Time, microsec

Particle size = 1.7 microns

U-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Signal level,V

Time, microsec

Particle size = 1.7 microns

U-component, High-pass filtered signal

-1.0 -0.5 0.0 0.5 1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Signal level,V

Time, microsec

Particle size = 1.7 microns

U-component, Digitized signal

-1.0 -0.5 0.0 0.5 1.0

0

100

200

300

400

500

600

700

800

Signal level, nW

Time, microsec

Particle size = 1.7 microns

V-component, Theoretical signal

-1.0 -0.5 0.0 0.5 1.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Signal level, V

Time, microsec

Particle size = 1.7 microns

V-component, Photomultiplier signal

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Signal level,V

Time, microsec

Particle size = 1.7 microns

V-component, High-pass filtered signal

-1.0 -0.5 0.0 0.5 1.0

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

Signal level,V

Time, microsec

Particle size = 1.7 microns

V-component, Digitized signal
Figure A.20.- Velocity magnitude and flow angle distributions for the input particles selected, particles that 

triggered acquisition, and particles that were measured.

Appendix A.63

 85 90 95 100 105 110 115 120

Velocity magnitude, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Normalized number of occurrances, percent

Input Velocity Magnitude

Click mouse to continue

 -25 -20 -15 -10 -5 0 5 10 15 20 25

Vertical flow angle, deg

 0

 2

 4

 6

 8

 10

 12

Normalized number of occurrances, percent

Input Flow Angle (Alpha)

 85 90 95 100 105 110 115 120

Velocity magnitude, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Normalized number of occurran ces, percent

Triggered Velocity Magnitude

 85 90 95 100 105 110 115 120

Velocity magnitude, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Normalized n umber o f occurrances, percent

Measured Velocity Magnitude

 -25 -20 -15 -10 -5 0 5 10 15 20

Vertical flow angle, deg

 0

 2

 4

 6

 8

 10

 12

 14

Normalized number of occurran ces, percent

Triggered Flow Angle

 -25 -20 -15 -10 -5 0 5 10 15 20

Vertical flow angle, deg

 0

 2

 4

 6

 8

 10

 12

 14

Normalized n umber o f occurrances, percent

Measured Flow Angle
Figure A.21.- U- and V-component velocity distributions for the input particles selected, particles that triggered 

acquisition, and particles that were measured.

Appendix A.64

Click mouse to continue

 85 90 95 100 105 110 115 120

Velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Normalized number of occurran ces, percent

Triggered U-Component

 85 90 95 100 105 110 115 120

Velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Normalized number of occurrances, percent

Input U-Component

 85 90 95 100 105 110 115 120

Velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Normalized n umber o f occurrances, percent

Measured U-Component

 -40 -30 -20 -10 0 10 20 30 40

Velocity, m/s

 0

 2

 4

 6

 8

 10

Normalized n umber o f occurrances, percent

Measured V-Component

 -40 -30 -20 -10 0 10 20 30 40

Velocity, m/s

 0

 2

 4

 6

 8

Normalized number of occurran ces, percent

Triggered V-Component

 -40 -30 -20 -10 0 10 20 30 40

Velocity, m/s

 0

 2

 4

 6

 8

Normalized number of occurrances, percent

Input V-Component
Figure A.22.- Distributions of differences between the particle parameter and the measured parameter for signal 

bursts that were accepted for processing.

Appendix A.65

Click mouse to continue

 -6 -4 -2 0 2 4 6

Velocity, m/s

 0

 10

 20

 30

 40

 50

 60

 70

 80

 90

 100

Normalized number of occurrances, percent

Measured U-Component Error

 -6 -4 -2 0 2 4 6

Velocity, m/s

 0

 10

 20

 30

 40

 50

 60

 70

 80

 90

 100

No rmalized number of occurran ces, percent

Measured V-Component Error

 -6 -4 -2 0 2 4 6

Velocity, m/s

 0

 10

 20

 30

 40

 50

 60

 70

 80

 90

 100

Normalized number of occurrances, percent

Measured Velocity Magnitude Error

 -4 -2 0 2 4

Vertical flow angle, deg

 0

 20

 40

 60

 80

 100

 120

Normalized number of occurrances, percent

Measured Flow Angle Error
Figure A.23.- Final distributions of velocity and flow angle, along with the final measurement errors (instrument 

precision) after the outliers were eliminated.

Appendix A.66

Click mouse to continue

 -6 -4 -2 0 2 4 6

Velocity, m/s

 0

 10

 20

 30

 40

 50

 60

 70

 80

 90

 100

Normalized n umber o f occurrances, percent

Final U-Component Errors

 85 90 95 100 105 110 115 120

Velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Normalized number of occurrances, percent

Final Velocity Magnitude

 85 90 95 100 105 110 115 120

Velocity, m/s

 0

 2

 4

 6

 8

 10

 12

 14

 16

Normalized number of occurran ces, percent

Final U-Component

 -6 -4 -2 0 2 4 6

Velocity, m/s

 0

 10

 20

 30

 40

 50

 60

 70

 80

 90

 100

Normalized n umber o f occurrances, percent

Final V-Component Errors

 -40 -30 -20 -10 0 10 20 30 40

Velocity, m/s

 0

 2

 4

 6

 8

 10

Normalized number of occurran ces, percent

Final V-Component

 -25 -20 -15 -10 -5 0 5 10 15 20

Alpha, deg

 0

 2

 4

 6

 8

 10

 12

 14

Normalized number of occurrances, percent

Final Flow Angle
Appendix B

Setup and Alignment of the TSI Fiberlight System for the 

14- by 22-Foot Subsonic Tunnel 

Laser Velocimeter System

Laser Safety

Always follow safety procedures outlined in the approved Laser Safety permit for the lab or 

facility, and the NASA – Langley Non-Ionizing Radiation Safety Manual prior to 

undertaking any laser related work. Perform all initial alignment procedures with the 

laser at low power settings.

Laser and Fiberlight System Alignment

It is assumed that the optical centerline of the laser and the Fiberlight multi-color beam 

generator are the same and that apertures and mirrors are installed as shown in 

Figure B.1.

Figure B.1.- Top and front view of the laser – Fiberlight setup.

Appendix B.1

Laser

Fiberlight

Laser Fiberlight

Aperture 1

Aperture 2

Optical Center Line

Mirror 1

Aperture 3 Mirror 2
Figure B.2.- Laser and Fiberlight with alignment optics.

Initial Alignment Procedures

1) With a beam block in front of the laser, power up the laser and adjust the alllines output power level to approximately 500 mW and allow it to come up to a 

stable operating temperature (10 to 20 minutes) before proceeding.

2) Using a power meter, peak the laser power using the adjustments on the high 

reflector at the rear of the laser.

3) Place a beam block in front of the fiber optic probe head.

4) Verify that the beam path is clear and that the mirrors are in place and appear 

to be pointed in the correct direction, as shown in Figure B.2.

5) Turn the laser power down to approximately 100 mW for initial alignment.

6) Use Mirror 1 to adjust the beam through the first aperture.

7) Use Mirror 2 to adjust the beam through the second and third aperture and the 

aperture located in front of the Fiberlight.

Appendix B.2
8) Verify that there is a beam block in front of the fiber optic probe head.

9) Proceed to the section on Installing the Transmitting Optics for aligning the 

Fiberlight on page 79 of the TSI Manual titled LDV/PDPA System Installation 

Manual.

10) When aligning the fiber optic couplers, adjust the laser output power level to 

500 mW, then peak the output of the fibers using a laser power meter to 

monitor the output. Peak the output of all four fibers before increasing the laser 

power into the Fiberlight. Increase the input power to the Fiberlight to 1 Watt, 

then re-peak the output of all four fibers. This process should be repeated in 

approximately 1 Watt increments until the input power to the Fiberlight is 

between 4 and 5 Watts. Table B.1 provides a guide for fiber output power 

versus laser power input. It is highly recommended that a log similar to the 

Table be kept every time a fiber alignment is performed.

Table B.1.- Laser power versus fiber optic output.

Laser Velocimeter Transmission Optics and Zoom Lens Alignment

1) Decrease the laser input power to the Fiberlight to the minimal level where the 

output is still maintained in both the green (514.5 nm) and blue (488.0 nm) 

lines. Place the alignment block against the alignment stops between the fiber 

optic head and Mirror 1 (Figure B.3), and verify that all of the beams pass 

through the block. The center line height of the package is 9 53/64 inches above 

the optical table. This is defined by the height of the center of the large zoom 

lens module. If height adjustment of the fiber optic probe head is necessary, 

loosen the set screw in the height adjustment knob on the lab jack and rotate 

the knob. Once the proper height is achieved, tighten the locking set screw.

2) If the beams are rotated with respect to the alignment block, loosen the large 

brass locking wheel under the probe and rotate the probe head. Once the 

desired orientation is attained, re-tighten the locking wheel.

3) Once the beams are made parallel, verify that Mirror 1 is in the proper position 

by placing the alignment block against the alignment stops between Mirror 1 

and Mirror 2. Verify that the beams pass through the block. If adjustments are 

needed, rotate the adjustment knobs on Mirror 1 to adjust the alignment.

Appendix B.3

Date Power In (w) 515 unshifted Pout 515 shifted Pout 488 unshifted Pout 488 shifted Pout

1/26/2010 0.5 22 21 48 52

1 60 59 80 90

2 144 155 151 177

3 225 255 228 255

4.3 270 358 300 327
Figure B.3.- Fiber optic head with transmit and receive optics.

4) Verify that Mirror 2 is in the proper position by placing the alignment block 

against the alignment stops between Mirror 2 and the small zoom (negative) 

lens module. Verify that the beams pass through the block. If adjustments are 

needed, then use the adjustment knobs on Mirror 2 to correct the alignment.

5) At this point the beams should be aligned and ready to pass through the zoom 

lens system. Reflections from the zoom lens are a good indication that the 

beams are properly aligned. If the alignment is correct, there will be a series of 

reflections that line up in the same plane as the input laser beams, Figure B.4. 

If the reflections are not in line, make small adjustments to the small zoom lens 

module until the reflections are aligned. Begin by making angle adjustments to 

get the reflections centered in a line in the plane of the laser beams. Follow this 

by using the left-right adjustments to bring the reflections all in a line. Several 

iterations may be required in order to obtain satisfactory alignment. Angle 

adjustments can also be made on the large zoom lens module, however the leftright and up-down positioning is fixed.

Appendix B.4
Figure B.4.- Reflection patterns from the zoom lens.

6) Adjust the distance between the zoom lens modules to focus the laser beams 

close to the area where the measurements are to be made.

7) Check the beam crossing using a microscope objective. Please refer to page 5-5 

in the TR/TM Series Fiberoptic Probes Operations Manual. If the beams have a 

good crossover (all beams overlap at the same point) then the initial alignment 

of the transmit optics is complete. If there are small differences where the laser 

beams cross, then minor adjustments can be made to the laser beams using the 

beam steering procedure on page 5-9 of the TSI Operator's Manual for the 

TR/TM Series Fiberoptic Probes. If the crossover is grossly off (>20-percent) 

then parallelism of the laser beams coming out of the fiber optic probe must be 

checked as outlined in Step 8. If the alignment is good proceed to Step 9.

8) Check parallelism of the laser beams.

NOTE: This procedure requires two additional 4-inch mirrors and a 

tripod. 

Place the alignment block in front of the fiber optic probe with the beams 

passing cleanly through the center of the holes. Place one 4-inch mirror 

between the alignment block and Mirror 1 at approximately 45-degrees to direct 

the laser beams off the optical table and across the room. Place a tripod and the 

second 4-inch mirror on the other side of the room to catch the beams and 

reflect them back on themselves. Examine the beams at the rear of the 

alignment block and verify that they all come back and overlap – ideally they 

should pass through the holes in the alignment block. If adjustments are 

required then refer to the section on Steering the Beams of TR 60 Probe on 

page 5-9 of the TSI Operator's Manual for the TR/TM Series Fiberoptic Probes.

Appendix B.5

Good lens alignment Lenses position misaligned

horizontal

Lenses position misaligned

vertical

Good lens alignment Lenses angle mismatch in

the horizontal plane

Lenses angle mismatched in

the vertical plane
9) Recheck zoom lens alignment as described in Step 5 and beam crossing as 

described in Step 7.

10) The last check in the optical alignment is to determine how well the receiver 

viewing volume overlaps the laser beam crossing. To verify the overlap refer to 

the section on Illuminating the Receiving Fiber on page 5-6 in the TR/TM Series 

Fiberoptic Probes Operations Manual.

Checking Signal Levels

1) Connect the TSI Photodetector Module (PDM1000) and TSI signal processor 

(FSA 4000), then run the FlowSizer software to enable the photodetectors. 

Refer to the section Installing the System Electronics and FlowSizer Software on 

page 93 of the LDV/PDPA System Installation Manual. NOTE: This system 

only uses the TSI Signal Processor (FSA 4000) and FlowSizer Software 

for powering and controlling the high voltage applied to the 

photomultiplier tubes.

2) Bring the laser power up gradually just as in the initial alignment procedure and 

peak the fiber couplers for maximum laser transmission. Do this until a 

maximum input power of 4 to 5 Watts is achieved. Do not assume that the 

alignment has held. Always increase the power in steps and verify the 

power levels out of the fibers. If the power levels are unbalanced 

STOP and recheck the initial alignment. This will prevent damage to 

the optical fibers.

3) Set up a portable particle generator at the measurement volume and observe the 

signals at the rear panel output of the TSI PDM-1000 with an oscilloscope. 

Signal levels should be at least 200 mV p-p with good modulation in the burst. 

If this is not observed recheck the alignment of the receiver fiber and the beam 

crossover. With the particles passing through the measurement volume in the 

horizontal plane, the centers of the signal bursts from the U- and V-components 

should be tracking together on the oscilloscope. If not, the V-component 

measurement volume is misaligned left-right. Now align the particle flow in the 

vertical direction. Again the centers of the signal bursts from the U- and 

V-components should be tracking together on the oscilloscope. If not, the 

U-component measurement volume is misaligned up-down.

4) If the measurement volume is to be moved along the optical axis (zoomed), 

checking the alignment of the measurement volumes, Step 3, should be repeated 

at several locations along the extent of the planned travel.

Appendix B.6
Appendix C

Data Acquisition and System Control Software

Installation and Functional Overview

Any software developed for a production environment must be intuitive, easy to use, free 

from failure, and provide sufficient user feedback to indicate proper functionality or 

identification of a problem along with instructions on how to correct the issue. In 

particular the Data Acquisition and System Control Software is designed to provide:

1) An intuitive, easy-to-use interface that enables the researcher to concentrate on 

the task at hand, and not on the functionality of the software;

2) System management to insure hardware/software configuration and 

synchronization with uniform and repeatable operation;

3) Control of the discretization of the analog signals obtained from the two 

photomultipliers, acquisition of auxiliary digital and digitized analog signals 

including azimuth encoder readings, and interarrival time measurements between 

signal bursts;

4) Archival management of all data collected so that the acquired measurements are 

preserved in a standardized manner to facilitate signal and data processing (onand off-line) with automated real-time backup, provide real-time user feedback, 

and support for off-line interrogation and analysis;

5) Control of the Signal/Data Processing computer operation including data 

transmission and storage, program control, and real-time user display of any issues 

found during processing that may affect data quality; and,

6) Control of the traversing system and remotely controlled turning mirrors used to 

position and orientate the laser velocimeter measurement volume within the flow 

field.

Methodology

The Data Acquisition and System Control software is the primary interface between the 

researcher and the collective system components during the course of a flow field 

investigation using the laser velocimeter. The software provides a seamless and 

transparent interface to the data collection subsystems, which include laser and optical 

system components as well as the signal conditioning, acquisition, and processing 

hardware, and the measurement volume positioning subsystem. In addition, the software 

provides the interface and data transfer path to the Signal/Data Processing computer as 

well as providing all control functions for the processing software.

Appendix C.1
The Data Acquisition and System Control software was developed using the National 

Instruments (NI) LabVIEW programming environment (Version 2010, SP1). The software 

consists of multiple custom program modules with supporting subroutines written in 

LabVIEW and C/C++. The modules employ NI supplied drivers and LabVIEW subVIs in 

conjunction with custom C/C++ DLLs to interact with the data collection hardware and the 

networked Signal/Data Processing computer to achieve the necessary functionality for 

production testing. The Data Acquisition and System Control software supports the 

following capabilities:

1) Easy to use graphical user interface (GUI);

2) System hardware initialization and control;

3) Data acquisition synchronization and management;

4) Particle interarrival time recording;

5) Conditional sampling of auxiliary inputs, e.g., rotor azimuth;

6) Data retrieval and archival;

7) Traverse mechanism control and management;

8) Signal/Data Processing triggering and control;

9) Processed data validation;

10) System progress logging;

11) Simulation device and signal management; and,

12) System performance monitoring and diagnostics.

Subtasks

In order for the Data Acquisition and System Control program to perform the above tasks, 

small background programs must be developed to provide the direct control of the external 

functions, task monitoring, control functions, and housekeeping tasks. Some of these 

modules are written in the LabVIEW environment while others, especially when execution 

speed is critical, in C/C++. The selection of tasks to be running at a given time is under 

the control of the main program as directed by the user and resulting selection of 

instructions to be executed. Using this methodology, the following benefits are obtained:

Segregation of the optional functionality from the top-level application as certain 

subtasks are enabled on an as needed basis, thus reducing memory/system 

requirements and resources; and,

Allows for certain software functions or subtasks to be reused, thus reducing 

duplication along with design, development and debug time. 

Subtasks in the LabVIEW Environment

Seven LabVIEW-based subtasks are employed by the Data Acquisition and Control 

program to support the various operations performed during the course of a typical data 

acquisition activity:

Appendix C.2
1) Storage Path Generator – This background task is responsible for generating the 

file storage paths (character strings) where the acquired data records will be stored 

on both computers. The generation of the data storage paths is a time consuming 

process and the ability to perform these operations in parallel with the acquisition 

of new data sets reduces overall acquisition time. The subtask is always launched 

when the Data Acquisition and Control program is started and it requires no direct 

user interaction.

2) One Shot Generator – This background task is launched at program start-up and is 

responsible for initializing and controlling the retriggerable one-shot pulse 

generation circuitry of the PXI-6602 Counter/Timer board (Chapter IV, page IV.3) 

installed in the PXI chassis. The one shot pulse signal is TTL positive and has a 

duration of 500 nsec. This pulse is used to control the signal validation hardware.

3) Log File Manager – This background task is launched at program start-up and is 

responsible for saving data acquisition information into a Log file once each data 

acquisition cycle is completed. The Log file contains information such as data 

series name, data acquisition rate and duration, number of signal bursts acquired 

and processed, convergence level, processing code and the location of the 

measurement volume when the data was acquired.

4) Traverse Mechanism Manager – This background task is responsible for the 

management of the Klinger model MC4 controller used to position the scan rig that 

in turn locates the measurement volume during a flow field test sequence. The 

subtask is launched when the user selects the Initialize Scan Rig button on the 

Scan Rig Management tab. Once the user has input the desired measurement 

location in the main program, this subtask will control the traversing mechanism 

to move the measurement volume to that location, and once completed, return the 

status to the main program. It is noted that this subtask will be modified as 

required to manage and control other traversing mechanisms, e.g., original 14-by 

22-Foot scan rig, pan/tilt mirror, etc.

5) Simulation Signal Manager – This auxiliary program is used to control and 

operate the Agilent 81150A Pulse Function Arbitrary Waveform generator. This 

generator is used to convert simulated or previously captured signal bursts into 

electronic signals that can be used to validate the operation of the data acquisition 

and Signal/Data Processing systems. This auxiliary program is launched when the 

user selects the Enable Test Mode button on the System Configuration tab.

6) 1024/Rev Encoder Simulator – This auxiliary background program is used to 

produce pulse trains that simulate the operation of a position encoder mounted to 

a rotating shaft such as those used during rotorcraft investigations. The subtask 

will generate a pulse train of 1024 pulses (1024/Rev) followed by a single (1/Rev) 

Appendix C.3
pulse signifying the zero azimuth position of the rotor. This 1/Rev is used to reset 

the pulse train counter signifying the beginning of the next revolution of the rotor.

7) Processed LV Data Manager – This background subtask is responsible for the 

management of statistical velocity measurement results from the most recent data 

ensemble returned by the Signal/Data Processing program. The subtask retrieves 

resolved flow-related quantities from output files generated by the Signal/Data 

Processing program and presents them to the user in both graphical and textural 

formats. These results duplicate those presented by the Signal/Data Processing 

program on the Signal/Data Processing computer monitor. Duplication was 

implemented because the operator needs to ascertain data quality, while the test 

engineer is more concerned with measurement values. Thus each has their own 

monitor. This subtask is launched when the user selects the Enable Online 

Processing and Enable Convergence Validation buttons on the System 

Configuration tab.

Data Management DLL (C-based Subtask) 

Since high-speed data transfer of the captured signal burst from the digitizer to the hard 

drives on both the data acquisition and Signal/Data Processing computers is of the essence, 

this function is accomplished using a C-based DLL controlled by the LabVIEW-based Data 

Acquisition and Control program.

Data Acquisition and Control Program

Installation and Setup

An installer CD has been developed to facilitate the installation of the Data Acquisition 

and Control program, its subtasks, and the LabVIEW Run-Time Engine including all 

necessary drivers, libraries, and other files needed for use on a computer lacking the 

LabVIEW development environment. The steps outlined below should be followed in 

combination with the sequence of installation dialogs to install the software:

1) Insert the Data Acquisition and Control program installation CD in the computer's 

CD or DVD drive.

2) Open a file manager (e.g., Windows Explorer, Free Commander, etc) and navigate 

to the CD (DVD) drive, e.g., Figure C.1.

3) Move the cursor to the setup.exe file (Figure C.1.) and double click the left mouse 

button to start the setup program. The program welcome screen, Figure C.2., will 

indicate that the program is ready to begin the installation process. Select the 

Next >> button to proceed.

Appendix C.4
4) Once the installation files have been loaded, the program destination directory 

dialog (Figure C.3.) will appear. If the Data Acquisition and Control program 

and/or the LabVIEW software are to be located in directories other than the 

default locations, select the appropriate Browse... button(s) to the right of the 

default directory fields to open a file manager where the desired directory can be 

selected. Once the desired directories have been established, click on the Next >> 

button to proceed.

5) The National Instruments and Microsoft License Agreements are presented in 

sequence (Figures C.4. and C.5.) for acceptance. If accepted, the installation of the 

LabVIEW software will commence, otherwise the installation program will 

terminate. Once each Agreement has been accepted, click the Next >> button to 

continue.

6) An information screen is then presented with a list of modules (Figure C.6.) that 

will be installed. Selecting the Next >> button will begin the installation of those 

modules.

7) Once the installation begins, a progress meter, Figure C.7., is displayed. If the 

installation completes without errors, the Completion Screen, Figure C.8., will be 

displayed. Click the Finish button to exit the installation program.

All modules and components should now be installed and the Data Acquisition and Control 

program is ready for use.

Data Acquisition and Control Program

Hardware Configuration and Data Acquisition Sequence

An overview of the organization of the hardware and their interactions, both analog and 

digital, can be found in the layout schematic shown in Figure C.9. The two coaxial cables 

transmitting the signals from the U- and V-component photomultipliers are electronically 

Teed with inputs to the monitoring oscilloscope (set to an input impedance of 50 ohms), 

the Trigger Generator, and the high-speed analog-to-digital converters in the NI PXI 

Acquisition System. When a signal burst is received that is of sufficient amplitude to 

trigger the oscilloscope, that trigger is also transmitted to the PXI System. This impulse 

trigger is modified by the PXI System to a 500 nsec TTL compatible signal which is 

transmitted to the Trigger Generator indicating that the scope has triggered. Once this 

pulse has been received, the Trigger Generator monitors the incoming signal burst to 

determine if 8 cycles are present. If so, the Trigger Generator will output a TTL 

compatible pulse (Master trigger) that will trigger the high-speed analog-to-digital 

converters to latch and store the U-and V-component signal bursts. The Master Trigger 

also latches and stores any auxiliary signals (analog or digital) that have been input to the 

low-speed analog/digital acquisition module. Although this process requires approximately 

half of the transit time of the particle through the measurement volume, the pre-triggering 

Appendix C.5
capabilities of the high-speed analog-to-digital converters insure that the entire signal 

burst is captured by each channel. It is noted that BNC switches are used to select and 

direct the appropriate signals to each module. It is mandatory that the same 

component signal used to trigger the oscilloscope is monitored by the Trigger 

Generator. For example, if the U-component signal is used to trigger the oscilloscope, 

that same signal should be routed through the switches to be input to the Trigger 

Generator.

Once the preset number of signal bursts have been acquired and stored in the PXI System, 

a data complete signal is sent to the Data Acquisition computer via the MXI bus to trigger 

the Data Acquisition and Control program to begin the data retrieval sequence. The 

program will transfer the two component data ensembles along with the auxiliary data 

from the PXI System to the hard drive on the Data Acquisition Computer, and via the 

Ethernet interface, to the hard drive on the Signal/Data Processing Computer. The 

program then develops the command file for the signal/data acquisition program and stores 

it on the Signal/Data Processing Computer's hard drive. The update of this file is the 

trigger for the Signal/Data Processing program to begin processing the data ensembles as 

instructed in the command file. The Signal/Data Processing program will develop a Log 

file for that data ensemble containing the velocity statistics for the U- and V-components 

(both individually and in full coincidence), velocity magnitude and flow angle. The Log file 

also contains a listing of the individual signal bursts: signal minimum and peak, and 

signal-to-noise ratio along with the computed particle U- and V-component velocity, 

velocity magnitude and flow angle, interarrival time, azimuth angle and transit time. In 

addition the program computes the U- and V-component mean and standard deviation 

every 100 acceptable signal bursts cumulatively to determine if statistical stationarity has 

been reached. Plots of these results are displayed followed by histogram plots of the Uand V-component velocities, velocity magnitude and flow angle. These plots are duplicated 

on the Data Acquisition computer by the Data Acquisition and Control program based on 

results transmitted by the Signal/Data Processing program. The results file contains data 

from the statistical stationarity test, the average minimum and maximum voltages, and 

the average signal-to-noise of the U- and V-component signal bursts. Once received by the 

Data Acquisition and Control program, these results are compared with user selected 

levels to determine the quality of the acquired data along with whether additional data 

ensembles should be acquired to reach statistical stationarity. The data acquisition and 

processing sequence is outlined in the flow diagram shown in Figure C.10. The green 

elements signify hardware steps, cyan elements – Data Acquisition and Control program, 

and red elements – Signal/Data Processing program. A more detailed explanation of each 

step is given below.

Appendix C.6
Program Start-Up Sequence

System Power Up 

Because the PXI chassis in which the data acquisition hardware resides is an extension of 

its host computer's PCI bus, it must be powered on prior to powering the Data 

Acquisition computer. After the PXI chassis has been powered up, wait approximately 

ten seconds before powering the Data Acquisition computer to allow the PXI chassis to 

initialize its various hardware and software elements.

Once the Data Acquisition hardware and computer have been powered, verify that the 

networked Signal/Data Processing computer has also been powered on.

System Log On

The default user name on both the Data Acquisition and Signal/Data Processing computers 

is lv and the default password is lv (both lower case). At the login prompt, the user should 

enter the following:

User Name: lv

Password: lv

Mount Network Disk Drive 

When a data acquisition cycle is completed, the acquired data resides in the Data 

Acquisition computer memory after being transferred from the PXI System. This data is 

then archived on the Data Acquisition computer hard drive and the Signal/Data Processing 

computer hard drive. In order for the data to be transferred to the Signal/Data Processing 

computer hard drive, that drive must first be mounted as a local drive on the Data 

Acquisition computer before initialization of the Data Acquisition and Control program. 

Mounting the remote disk drive as a local drive on the Data Acquisition computer is 

accomplished by:

1) Open Windows Explorer to display a drive window similar to the one shown in 

Figure C.11.

Since during the software installation process (page C.5.) the remote drive was 

mounted, it should be displayed in the group labeled Network Location(s). If the 

drive has an X over the storage locations available to the Signal/Data Processing 

computer (as shown in Figure C.11.), the drive did not automatically mount when 

the two computers were powered on. In order to mount and share a disconnected, 

but visible drive continue below.

Appendix C.7
2) Select the desired drive by a left mouse click with the cursor over the drive name 

(NOTE: Drive E: is the default drive name for the remote drive). This will cause 

the display of the Log In screen for the network Domain LVACQ (Figure C.12.).

Enter the user name and password below, then select OK:

User Name: lv

Password: lv

Verify that the remote drive has been successfully mounted by the absence of an X 

over drive E:. Now the Data Acquisition and Control program can be launched.

Launching the Data Acquisition and Control Program (Standalone)

To begin, the user should navigate via the file manager to the disk drive where the 

program was installed (page C.5.), and select the directory named LV Data Acquisition 

Application.

The main program can then be launched by placing the cursor over the executable file: LV 

Data Acquisition and double-clicking the left mouse button. Once the program has been 

launched, the user is presented with the Opening (Main) Screen shown in Figure C.13. 

After a few seconds the dialog window shown in Figure C.14. will appear prompting the 

selection of an Initialization (.INI) file that contains the start-up settings for the Data 

Acquisition and Control program. The following two options are available:

1) Default.ini – The program settings used during the last execution of the Data 

Acquisition and Control program as stored stored in the default .INI file 

(LV_Acq_Setup.ini) and located in the sub-directory named Config in the 

directory containing the Data Acquisition and Control program. The contents of 

this file are automatically updated to the settings present when the program is 

terminated.

2) User.ini – This option allows the user to select an alternative set-up configuration 

via the file manager, shown in Figure C.15., that opens when this option is selected. 

The option allows the user to employ previous configurations by copying and 

renaming the default settings file (LV_Acq_Setup.ini) to preserve the current 

settings for later use.

Once the set-up (.ini) file has been interrogated by the program to configure the program, 

the Opening (Main) Screen is once again presented, Figure C.13. This screen is divided 

into two sections: The Program Navigation Bar on the left (Figure C.16.), and the 

Program Configuration/Management Panel to the right (Figure C.17.).

Appendix C.8
Menu Navigation

Mechanisms have been incorporated into the Data Acquisition and Control program to 

provide the user with a great deal of flexibility in the way it can be used. Controls along 

with support subroutines, subprograms and simulators have been developed that allow the 

user to choose signal types, sources and ranges as well as options that enable the 

functionality of the laser velocimeter system to be verified prior to formal deployment of 

the instrument in research activities. Additionally it supports the ability to manage 

devices other than those used in the data collection process from a single interface. The 

various program controls and options are arranged on the user interface in a manner that 

affords the user with an easy way to configure and use the system. Access to the system 

components and settings is obtained via the selection buttons located on the left side of the 

Opening (Main) Screen, Figures C.13. and C.16.

The intention of this Appendix is to provide an overview of the processes available in the 

Data Acquisition and Control program. Thus the individual screens will be described as to 

their general function, with the detailed functions described in Appendix D. The 

functionality is presented in the order in which the options might be used during the 

course of a laser velocimeter flow field investigation. It is noted that the user will find that 

for a majority of applications, the default settings will provide the necessary controls. 

However, to provide system flexibility and to support various test scenarios where the 

default settings would not be appropriate, the necessary controls are provided to customize 

the settings as needed. It is advised that if custom settings are used, the 

LV_Acq_Setup.ini file should be copied and renamed to preserve the original default 

settings for future use.

Configure System 

Selecting the Configure System button from the Navigation Bar will open the display 

shown in Figure C.17., (Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17.). Within →

this display the user is provided with access to controls and options required to configure 

the data acquisition hardware, data storage, and validation components which ultimately 

define the manner in which the data ensembles will be collected and archived. Typically 

the user will adjust the settings, if necessary, at the start of the investigation and utilize 

them throughout the flow field investigation. An overview of the functions in each group 

follows:

Select Desired Options – These controls shown in Figure C.18., (Figures C.13. 

(C.16.) [CONFIGURE SYSTEM] C.17. (C.18.)), → provide the user with the 

ability to:

1) Enable/Disable signal/data processing in real time;

2) Enable/Disable the measurement of rotor azimuth via the shaft encoder;

3) Enable/Disable communications with the wind tunnel data acquisition 

hardware;

Appendix C.9
4) Enable/Disable the input of synthetic signal bursts from the arbitrary 

waveform generator;

5) Enable/Disable the input of a simulated shaft encoder (only active if the 

measurement of the shaft encoder is enabled);

6) Enable/Disable warning messages indicating that statistical 

stationarity of the flow measurements has not been attained based on the 

user selected threshold; and,

7) Enable/Disable menus containing data acquisition hardware settings.

LV Burst Signal Digitizer Management – The controls found in this sub-panel, 

Figure C.19., (Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17. (C.19.)) → , 

define the operation of the high-speed analog-to-digital converters (National 

Instruments PXI-5152 8-bit, 2.0 GS/s, Chapter IV.2).

Auxiliary Channel Analog Input – The controls found in this sub-panel, 

Figure C.20., (Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17. (C.20.)) → , 

define the functionality of the auxiliary channel analog inputs. Auxiliary 

channels are provided to allow conditional sampling of analog signals 

produced by instruments external to the laser velocimeter. These 

instruments would typically be used to coordinate measurements of other 

flow phenomena or model conditions with the instantaneous velocity 

measurements. These signals are input to the National Instruments 

PXI-6120 Multifunction Data Acquisition Module, Chapter IV, page IV.2.

Data Storage Management – The controls found in this sub-panel, Figure C.21., 

(Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17. (C.21.)) → , define the 

directory paths for archival storage of the acquired data, the manner in which 

the file name is configured, and whether the data should be stored in either 

ASCII or binary form. Also user comments/notes regarding the test can be 

entered and will be recorded in the ensemble LOG file. 

LV Data Acquisition Management – The controls found in this sub-panel, Figure 

C.22., (Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17. (C.22.)) → , define 

the characteristics of the acquisition of each data ensemble, convergence 

threshold, and whether the laser velocimeter traversing mechanism should be 

automatically moved at the completion of the acquisition of a data ensemble.

Data Acquisition Conditions – The controls found in this sub-panel, Figure C.23., 

(Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17. → (C.23.)), provide the 

user with the ability to record the environmental test conditions and the 

characteristics of the particles injected in the flow. These inputs will be 

recorded in the ensemble LOG file.

Appendix C.10
Control Scan Rig 

Laser velocimetry, being a point measurement technique, requires that the measurement 

volume be moved throughout the flow field in order to develop an understanding of the 

flow properties. This control button, Figure C.16., will open the display shown in Figure C. 

24., (Figures C.13. (C.16.) [CONTROL SCAN RIG] C.24.). At first this display appears →

to be cluttered and complicated, but when taken one group at a time, their functions are 

logical. At the highest level, there are actually three displays as selected by the tabs at the 

top of the display:

Controls – The primary interface to the scan rig. The display presents current 

location, automatic scan control options, scan speed and acceleration, and 

communications information.

Scan File Data – Contains information retrieved from a scan rig position control file 

selected by the user.

Status/Information – Contains status and related information pertaining to the use 

of the scan rig.

It is noted that the current control functions are specific to the Klinger MC4 family of 

traversing mechanisms. If another traversing mechanism is used, the underlying drivers 

and subroutines must be written to access the capabilities of the rig to place it under the 

full control of the Data Acquisition and Control program. However, the prime functions 

and capabilities shown in Figure C.24. will be maintained if possible.

The following sub-panels are found in the Controls display:

Scan Rig Functions – The controls found in this sub-panel, Figure C.25., (Figures 

C.13. (C.16.) [CONTROL SCAN RIG] C.24. (C.25.)), → provide the basic 

control of the scan rig along with the development of a grid index via a 

separate dialog, Figure C.26., (Figures C.13. (C.16.) [CONTROL SCAN RIG] →

C.24. (C.25.) [Create Scan Grid File] C.26.), → and moving the rig based on 

positions stored in the index.

Klinger MC4 Scan Rig Status Display – This sub-panel, Figure C.27., (Figures C.13. 

(C.16.) [CONTROL SCAN RIG] C.24. (C.27.)), → reflects the information 

presented on the front panel display of the MC4 controller along with 

communication status information.

Set Scan Rig Index – This sub-panel, Figure C.28., is displayed when the Scan To 

Index control is selected, (Figures C.13. (C.16.) [CONTROL SCAN RIG] →

C.24. (C.25.) [Scan To Index...] C.28)) → . The control moves the measurement 

volume to the position obtained at the selected index in the table containing 

the input grid.

Appendix C.11
Klinger MC4 Scan Rig Control Panel – This sub-panel, Figure C.29., (Figures C.13. 

(C.16.) [CONTROL SCAN RIG] C.24. (C.29.)), → contains the controls that 

give the user additional control of the scan rig and can be used in combination 

with the capabilities provided by the Scan Rig Function controls.

MC4 Scan Rig Position Info – Inches – This indicator, Figure C.30., (Figures C.13. 

(C.16.) [CONTROL SCAN RIG] C.24. (C.30.)), → displays the current position 

of the measurement volume for the four scan rig axes in inches.

MC4 Scan Rig Position Info – Meters – This indicator, Figure C.31., (Figures C.13. 

(C.16.) [CONTROL SCAN RIG] C.24. (C.31.)), → displays the current position 

of the measurement volume for the four scan rig axes in meters.

Acquire Data 

Selection of this control button, Figure C.16., will open the display shown in Figures C.32. 

and C.33., (Figures C.13. (C.16.) [ACQUIRE DATA] C.32. [ → Cumulative Results Tab] →

C.33.)). The display presents both controls and indicators to the operator that are 

typically used during the data acquisition process. Note that the plots indicate the results 

produced after acquiring 2429 signal burst captures.

The following sub-panels are found in the Data Acquisition display (Figure C.32.):

Data Acquisition Controls – This sub-panel, Figure C.34., (Figures C.13. (C.16.) 

[ACQUIRE DATA] C.32. (C.34.)), → provides the user with the controls and 

status information applicable to the data acquisition process. The primary 

control, Start Data Acquisition, begins the sequence of events to control the 

data acquisition hardware, software execution, operation sequencing, file 

management, progress monitoring, data retrieval, and Log file management. 

Once started the data acquisition continues until: a) the requested number of 

data samples have been acquired; b) the specified timeout limit is reached; or, 

c) the operator activates the Terminate Data Acquisition button.

Data Acquisition Information – This sub-panel contains indicators to provide the 

user with status information regarding the active data acquisition cycle.

System Settings – This sub-panel contains indicators that present the system 

setting status.

At the conclusion of a given data acquisition cycle, the Data Acquisition and Control 

program begins interrogating the Return file generated by the Signal/Data Processing 

program. When this file is updated, indicating that the processing program has completed 

its task and that the results have been written to the file, the Data Acquisition and Control 

program retrieves the results and presents them to the user as shown in Figures C.32. and 

C.33. During the interrogation period, the operator is presented with the dialog shown in 

Appendix C.12
Figure C.35., (Figures C.13. (C.16.) [ACQUIRE DATA] C.32. (C.34.) [ → START DATA 

ACQUISITION] C.35.). → If the retrieved results show that the convergence level is higher 

than the user specified level (Figure C.22.) a warning message, Figure C.36., (Figures C.13. 

(C.16.) [ACQUIRE DATA] C.32. (C.34.) [ → START DATA ACQUISITION] C.35. →

{Convergence Test Failed} C.36.), → is displayed. This message contains the number of 

processed signal bursts, the resultant convergence level and the specified convergence level 

along with a recommendation to acquire another ensemble at the current measurement 

volume location.

It should be noted that selecting the CONTINUE button in Figure C.35., will bypass the 

opportunity for the data processing operation to conclude before the next data ensemble is 

requested. This prohibits the retrieval of the results needed to evaluate the quality of the 

previous data ensemble (although this data will still be preserved and presented by the 

Signal/Data Processing computer). It is recommended that the operator wait until the 

processing phase is completed and the results reviewed to determine the next course of 

action.

Since the Signal/Data Processing program was designed with a 10,000 signal burst limit for 

each component, the Data Acquisition program has an acquisition limit test. If the user 

requests more than 10,000 signal bursts to be acquired, either as a single ensemble or the 

sum of multiple ensembles at the same location, the Data Acquisition program will present 

the warning shown in Figure C.37., (Figures C.13. (C.16.) [ACQUIRE DATA] C.32. (C.34.) →

{>10,000 Signal Bursts Requested} C.37.). → Here the user can adjust the requested 

number of signal bursts to be processed to remain below the limit. If this is disregarded, 

the Signal/Data Processing program will process the first 10,000 signal bursts and ignore 

the rest. Thus, if 10,000 signal bursts do not satisfy the convergence test for statistical 

stationarity, it cannot be satisfied at that location.

System Diagnostics

Selection of this control button, Figure C.16., will present the user with the information 

panel shown in Figure C.38., (Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38.). →

This panel contains a tab-based interface with settings and feedback/status elements 

related to the data acquisition process. In most circumstances the operator will not need 

to interact with this diagnostic information as it is primarily maintained for the purpose of 

providing feedback to the system developer, although it might answer the question of why 

doesn't a component yield usable signal bursts. For example, in the U-component signal 

plot shown in Figure C.38., (Acquired Data tab) only a jitter of the least significant bit in 

the high-speed analog-to-digital converter is found instead of the typical signal burst 

shown in the V-component. If this situation occurs, the user should begin searching for 

the problem because any further acquisitions would not yield usable measurements.

Acquired Data tab – This tab presents the screen shown in Figure C.38., which 

presents the results from the most recent data ensemble. Activation of the 

Appendix C.13
Plot Data? control (Figure C.39., (Figures C.13. (C.16.) [SYSTEM 

DIAGNOSTICS] C.38. (C.39.))), → provides the user with a monitoring 

capability to view the acquired U- and V-component signal bursts. The 

displayed signal traces are updated at the rate specified by the user via the 

Plot Delay (ms) control. Normally the Plot Data? control is turned off unless 

there is a suspected problem because of the time required to view the signal 

bursts.

Hardware tab – This tab presents the screen shown in Figure C.40., (Figures C.13. 

(C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Hardware Tab] C.40.), → which 

reflects the configuration of the data acquisition hardware as defined by both 

the operator and settings applied within the control software. At a glance the 

reader will recognize that there are a myriad of settings and parameters 

available; thus reflecting both the flexibility of the PXI-based hardware and 

configuration utilized to realize a system capable of satisfying the 

requirements of laser velocimetry. Information presented on this tab is 

grouped according to device or function where possible. Detailed explanations 

of these settings/information are presented in Appendix D.

Information tab – This tab presents the screen shown in Figure C.41., 

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Information Tab] →

C.41.), which provides feedback of information reported from the system 

components rather than user settings. The ability to retrieve and present 

this information provides confirmation that the system is configured 

according to the user's specifications.

Sub-Task Info tab – The information presented from this tab, Figure C.42., 

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Sub Task Info Tab] 

→ C.42.), pertains to the background tasks conducted in software as activated 

and controlled by the Data Acquisition and Control program, and not the 

program operator. Some of these sub-tasks are always used while others are 

used as needed. A discussion of these subtasks along with their functions is 

presented beginning at Appendix D, page D.31.

Simulation Signal Task Info tab – The information presented by this tab, 

Figure C.43., (Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. →

[Simulation Signal Task Info Tab] C.43.), → outlines the location and type of 

simulated data used to validate the operation of the data acquisition system. 

The simulation data can originate directly from a file, a file selected to drive 

the arbitrary waveform generator, or even files captured from a particle 

generator or flow field measurements.

Log File Info tab – The information presented from this tab, Figure C.44., 

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Log File Info Tab] →

Appendix C.14
C.44.), is related to the Log file that maintains the data acquisition 

information produced during the course of a flow field investigation. These 

Log files are uniquely identified by date and measurement time.

Data Management Settings/Info tab – This panel, Figure C.45., (Figures C.13. 

(C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Data Management Settings/Info 

Tab] C.45.), → presents information related to the data retrieval and storage 

operations of the system as well as status information related to the various 

hardware tasks.

Processed Results tab – This panel, Figure C.46., (Figures C.13. (C.16.) [SYSTEM 

DIAGNOSTICS] C.38. [ → Processed Results Tab] C.46.), → contains 

information related to the processing of the data ensembles. This 

information is extracted from a file generated during the signal/data 

processing phase. Information gleaned from this file, in particular 

Convergence Level is used to determine if another data ensemble should be 

acquired at the present measurement volume location in an attempt to reach 

flow statistical stationarity. This test is only performed if the Convergence 

Validation test has been enabled (Configuration: System Options).

System Information

Selection of this option, (Figures C.13. (C.16.)), causes a panel containing pdf reader 

commands that will display information/help files pertaining to the Data Acquisition and 

Control program and the Signal/Data Processing program. Included in these files are the 

portions of this document that pertain directly to the hardware/software used in the laser 

velocimeter.

Quit

Selection of this option, (Figures C.13. (C.16.)), terminates the Data Acquisition and 

Control and the Signal/Data Processing programs.

Program & System Status 

At the bottom of the Navigation Bar, (Figures C.13. (C.16.)), status information is provided 

in a quick look format with a progress monitor indicating the current function being 

performed during a data acquisition cycle. The number of data ensembles collected during 

a given test is also displayed. 

Appendix C.15
Figure C.1.– Windows Explorer window showing LV Data Acquisition program installation directory.

Figure C.2.– LV Data Acquisition application installation/setup program – Welcome Screen.

Appendix C.16

LV Data Acquisition Program Setup

LV Data Acquisition Program Installation Package

NASA Langley Research Center

Hampton, Virginia
Figure C.3.– LV Data Acquisition application installation/setup program – Program Destination Directory Dialog.

Figure C.4. - LV Data Acquisition program installation/setup program – National Instruments License Agreement.

Appendix C.17
Figure C.5. - LV Data Acquisition program installation/setup program – Microsoft Component License Agreement 

Figure C.6. - LV Data Acquisition program installation/setup program – Installation Review Dialog.

Appendix C.18
Figure C.7. - LV Data Acquisition program installation/setup program – Installation Progress Dialog.

Figure C.8 - LV Data Acquisition program installation/setup program – Installation Complete Dialog.

Appendix C.19
Figure C.9.– Data Acquisition / Signal/Data Processing system hardware interconnection diagram.

Appendix C.20
Figure C.10.– Data Acquisition / Signal/Data Processing system operational flow diagram.

Appendix C.21

Yes

Yes

Yes

Yes Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

No

No

No

No

No

No

No

Start

Power Up

PXI Chassis

Monitor LV

Data Processing?

Enable Online

Processing Option

Power Up

LV Data Acquisition

& Processing Computers

Login To

LV Data Acquisition

& Processing Computers

Mount LV Data Processing

Computer Network Drive

Record Rotor

Position?

Enable Rotor

Encoder Sampling Option

Process

LV Data Online?

Launch LV Data Processing

Program On LV Data

Processing Computer

Enable DAS

Communications Option

Initialize LV Data

Processing

Program Settings

Use Synthetic

LV Signals?

Launch LV Data Acquisition

Program On LV Data

Acquisition Computer

Load Data Acquisition

.Ini File &

Initialize System

Select Configure

System Button

Enable Test

Mode Option

Connect Arbitrary

Waveform Generator to

LV Data Acquisition

Computer (USB) & Power Up

Configure AW G

Options

Configure LV Data

Acquisition Options

Select Synthetic

LV Signals

Select Configure

Scan Rig Button

Configure

Scan Rig

Data Grid

Complete?

Go To Scan Rig

Decision To Continue

Scan Rig

Required?

Convergence

Criteria Satisfied?

Process Captured

LV Signal Bursts

Configure Advanced

HW Settings

Advanced HW

Settings

Required?

Enable Advanced

HW

Settings Option

Time

Out?

Required #

Samples

Acquired?

Enable Rotor

Encoder Simulator Option

Monitor

Convergence?

Enable Convergence

Validation Option

Sample Auxiliary

Parameters

Capture LV

Signal Bursts

Select Start

Data Acquisition

Button

Use Rotor

Encoder

Simulator?

Select Acquire

Data Button

Position LV

Sample Volume

Sample Tunnel

DAS Info?

Store

Acquired

Samples

Store

Acquired

Samples
Figure C.11.– Windows Explorer window.

Figure C.12.– Password entry prompt for Network to mount remote disk drive.

Appendix C.22
Figure C.13.– Opening (Main) screen for the Data Acquisition and Control program.

Figure C.14.– Initialization File prompt.

Appendix C.23
Figure C.15.– File manager window to select User Initialization File.

Figure C.16.– Data Acquisition and Control program Navigation Bar.

Appendix C.24
Figure C.17.– Data Acquisition and Control program configuration/management panel (Default configuration).

Figure C.18.– Data acquisition options (Disabled &Enabled shown).

Appendix C.25
Figure C.19.– LV Burst Signal Digitizer settings.

Figure C.20 .– Auxiliary analog input channel management settings.

Figure C.21.– Data Storage Management settings

Appendix C.26
Figure C.22.– LV Data Acquisition Management settings.

Figure C.23.– Data Acquisition Conditions.

Appendix C.27
Figure C.24.– Scan Rig Management Interface (System Online).

Figure C.25.– Scan Rig Function controls.

Appendix C.28
Figure C.26.– Scanner Position Generator dialog.

Appendix C.29
Figure C.27.– Klinger MC4 Scan Rig Position/Status Display.

Figure C.28.– Scan rig position manual index selection dialog.

Figure C.29.– Klinger MC4 Scan Rig Control Panel.

Appendix C.30
Figure C.30.– MC4 Scan Rig Position Info – Inches.

Figure C.31.– MC4 Scan Rig Position Info – Meters.

Figure C.32.– Data Acquisition Management Control Interface (Post data acquisition Current Results tab shown).

Appendix C.31
Figure C.33.– Data Acquisition Management Control Interface (Post data acquisition Cumulative Results tab 

shown).

Appendix C.32
Figure C.34.– Data acquisition management controls/settings.

Figure C.35. - LV data processing wait dialog

Appendix C.33
Figure C.36 – Data processing results presentation dialog

Figure C.37 – Sample quantity adjustment dialog

Appendix C.34
Figure C.38.– Data Acquisition Diagnostics Information Panel (Acquired Data Tab).

Figure C.39.– Data plot options.

Appendix C.35
Figure C.40.– Data Acquisition Diagnostics Information Panel (Hardware Tab).

Figure C.41.– Data Acquisition Diagnostics Information Panel (Information Tab).

Appendix C.36
Figure C.42.– Data Acquisition Diagnostics Information Panel (Sub Task Info Tab).

Figure C.43.– Data Acquisition Diagnostics Information Panel (Simulation Signal Task Info Tab).

Appendix C.37
Figure C.44.– Data Acquisition Diagnostics Information Panel (Log File Info Tab).

Figure C.45.– Data Acquisition Diagnostics Information Panel (Data Management Settings/ Info Tab).

Appendix C.38

0.2508
Figure C.46.– Data Acquisition Diagnostics Information Panel (Processed Results Tab).

Appendix C.39
Appendix C.40
Appendix D

Data Acquisition and System Control Software

User Input and System Information Definitions

An overview of the operation and display screens of the Data Acquisition and System 

Control program is given in Appendix C. The specific details and definitions of each user 

interface and system information display are presented in this Appendix. The descriptions 

are given in the same order as found in the overview. The major sections are named for the 

primary program functions found in Figure C.16. Many of the figures referred to are 

contained in Appendix C. Also the background and auxiliary sub-tasks are defined along 

with their functions, displays, inputs and results. Figures for the sub-tasks are found in 

this Appendix.

Nomenclature

Graphical User Interface Inputs/Outputs

Each input/output/display port in the Data Acquisition and Control Program graphical 

user interface will be classified by the following nomenclature and defined screen by screen 

in this Appendix.

[Button] Any field that enables a function/screen by click on, click 

off operation.

[Display] Any field where results/settings/graphs, typically color on 

black, are displayed. Displays can not be changed directly 

by the user.

[Drop Down Menu] This field will have a downward pointer on the right side 

of the field. Clicking on the pointer will drop a menu 

from which the user may select the desired setting.

[File Manager Entry] This field will have a folder icon on the right side of the 

field. Clicking on this folder icon will open a file manager 

that can be used to select the desired file whose full 

path/name will be placed in the field.

[Indicator] Any circle, box, or other shape that lights to show that its 

monitored condition is enabled. This field can not be 

changed directly by the user.

[Indicator Button] Any circle, box, or other shape that lights or turns off to 

show the state of the parameter identified by the button 

as it is clicked on/off.

Appendix D.1
[Switch] A field that appears as a toggle or rocker switch to change 

the on/off status of the listed parameter.

[Text/Value Entry Field] A field where text and/or values can be entered/changed 

by the user.

[Value Entry Field] A field where values can be entered/changed by the user.

Equipment / Signals

Definitions

(Hardware shown in Figure C.9.)

Arbitrary Waveform Generator (AWG) – Not shown in Figure C.9.

A high-speed waveform generator capable of two channel output at digital-toanalog rates of up to 1.0 GHz. The Agilent 81150A Pulse Function / 

Arbitrary Waveform Generator is used to convert synthetic or previously 

captured signal burst waveforms into electronic signals that simulate signal 

bursts arriving from the laser velocimeter optical system.

Data Acquisition and Control Software (DA/C software)

The LabVIEW based software that controls the acquisition of laser 

velocimetry and auxiliary sensor data, manages and archives the data on 

computer hard drives, controls the traversing mechanism holding the laser 

velocimeter optics, and controls the execution and settings of the Signal/Data 

Processing Software.

Digital Phosphor Oscilloscope (Scope)

The digital oscilloscope that is used to monitor the signal bursts from the 

laser velocimeter photomultipliers, and used to generate the source trigger for 

the LV Data Valid Trigger via the LVTG (Master Trigger).

Ethernet Interface 

The electronic hardware that supports communication between the two 

networked computers using standard 1.0 Gb/sec Ethernet communication 

protocol mechanisms.

High-Speed Analog-to Digital Converter (High-speed digitizer)

The 2-channel high-speed analog-to-digital converter, PXI-5152, typically 

operated at 1.0 GHz per channel, digitizes the signal bursts from the U- and 

V-component photomultipliers.

Laser Velocimeter Trigger Generator (LVTG)

The custom electronics system that, once triggered by the PXI system, 

performs the validation of the signal burst by insuring that the burst contains 

Appendix D.2
at least eight cycles. If the signal is validated, the LVTG generates the Master 

Trigger used for all signal burst related data acquisition functions.

LV Data Acquisition Computer (DA/C computer)

The computer executing the Data Acquisition and Control Software. This 

computer provides the user interface to the instrumentation.

LV Data Acquisition System (LVDAS)

The electronics, computers, and communications hardware shown in 

Figure C.9., along with the Data Acquisition and Control Software.

LV Data Processing Computer (Processing computer)

The computer executing the Signal/Data Processing Software. This computer 

is controlled remotely by the Data Acquisition and Control Software.

LV Data Valid Trigger (Master Trigger)

The trigger pulse generated by the Laser Velocimeter Trigger Generator 

following receipt of the Scope Trigger Valid One Shot Pulse as modified by the 

PXI-6602, and validation that eight cycles have occurred in the monitored 

component signal burst. The Master Trigger is used as the trigger source for 

all signal burst related data acquisition functions.

Multifunction Analog-to-Digial Converter/Counter/Timer (Multifunction module)

The multifunction module, PXI-6120, is used to conditionally sample external 

sensors, shaft encoders, etc. It is also used to generate certain simulation 

functions to validate proper operation of the Data Acquisition and Control 

software. 

MXI Bus (MXI Bus)

The electronic communication hardware that provides two way 

communication between the PXI chassis and enclosed hardware and the LV 

Data Acquisition Computer.

National Instruments Measurement & Automation Explorer (NI-MAX)

National Instrument, Inc. instrumentation control microcode accessed and 

directed by programs operating under the National Instrument, Inc. 

programming language LabVIEW. NI-MAX provides the driver interface 

between the control software and the data acquisition hardware. All 

hardware elements controlled via the system software must be configured 

through NI-MAX before they can be accessed.

PXI Based LV Data Acquisition System (PXI system)

The National Instrument PXI chassis that contains the high-speed analog-todigital converters, analog/digital/timer/counter multifunction device, interface 

Appendix D.3
and communication circuits, and power supplies. This is the primary data 

acquisition hardware.

Scope Trigger Out (Scope trigger)

The trigger that is generated when the monitored photomultiplier signal 

crosses the trigger level set by the user. It is normally set to 80-percent of the 

amplitude from the median signal bursts.

Scope Trigger Valid One Shot Pulse (Trigger One Shot)

The one shot trigger pulse, 500 milliseconds in duration, generated by the 

counter/timer module (PXI-6602) upon receipt of the trigger signal from the 

digital oscilloscope.

Signal/Data Processing Software (Processing Software)

The FORTRAN based software that determines the U-and V-component 

velocities, velocity magnitude, and flow angle of particles passing through the 

laser velocimeter measurement volume based on the frequency content of the 

captured signal bursts. The program also computes the full statistics of each 

data ensemble, and displays the results in the form of histograms and text in 

real time.

Virtual Instrument Software Architecture (VISA)

Instrument control drivers and status templates used by National 

Instruments, Inc. NI-MAX microcode to provide instrument control and 

status capabilities to programs written in the National Instruments, Inc. 

LabVIEW environment.

Configure System

Data Acquisition and Control Program

Configuration/Management Panel

Figure C.17.

(Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17.) →

Select Desired Options

Figure C.18.

(Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17. (C.18.)) →

All controls in this sub-panel are click on / click off format.

Enable Online Processing – [Button]: Enables mechanisms that facilitate communication 

between the DA/C computer and the Processing computer to activate real-time signal/data 

processing of the data ensembles acquired during a flow field investigation.

Appendix D.4
Enable Rotor Encoder Sampling – [Button]: Enables conditional sampling of the rotor 

encoder position to provide velocity versus azimuth angle correlations.

Enable DAS Communications – [Button]: Enables communication with the wind tunnel 

data acquisition computers (NASA Langley OADAS computer system) to obtain the test 

parameters for each data ensemble.

Enable Test Mode – [Button]: Enables synthetic signal bursts produced by an Arbitrary 

Waveform Generator (AWG) to be used to verify the operation of the Data Acquisition 

System. When the Test Mode option is selected, the user will be prompted for additional 

inputs at the start of the next data acquisition cycle. At that time, the functionality and 

source of the synthetic signal bursts will be defined. It is noted that origin of these signal 

bursts may be the Monte Carlo simulation of a laser velocimeter, or previously captured 

signal bursts from a rotating wheel, Royco particle generation flow, laboratory testing, or 

flow field investigations. Communication and management of the AWG is performed over 

a USB 2 interface that is transparent to the user once the data acquisition cycle is 

initiated. NOTE: The described Data Acquisition System supports the use of the Agilent 

8115A Pulse Function Arbitrary Generator only.

Enable 1024/Rev Simulator – [Button]: Generates a simulator that mimics the operation 

of the rotor position encoder. This would be used during system verification activities. 

The simulator assumes that a 1024 per revolution encoder with a 1 per revolution reset 

pulse is used on a shaft rotating at 2800 rpm. Timing is absolute and the selection of 

encoder count (azimuth angle) is directly related to the acquisition time marker of each 

captured signal burst.

Enable Convergence Validation – [Button]: Establishes a user feedback that is based on 

the comparison of the results from the statistical stationarity test, Appendix E.2-3., with 

the user selected threshold, Figure C.22. If the control is enabled and the statistical 

stationarity test results are larger than the threshold, a warning message will be displayed 

suggesting that another data ensemble should be acquired at this location. If another 

ensemble is acquired, both ensembles will be processed as a single ensemble and the test 

applied again. This can continue until the ensemble reaches 10,000 signal bursts at which 

point no further data can be gathered.

Advanced HW Settings – [Button]: Provides the user with additional (advanced) control 

over the settings used in the data acquisition system (Figure D.1).

LV Burst Signal Digitizer Management

PXI-5152 High-Speed Digitizer

Figure C.19.

(Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17. (C.19.)) →

Input Voltage Range (V p-p) – [Drop Down Menu]: Selects the peak-to-peak voltage range 

of the high-speed analog-to-digital converters. The range setting should be selected so that 

Appendix D.5
maximum resolution can be realized without saturating the digitizers. Refer to the signal 

amplitudes displayed on the monitoring oscilloscope that are generated by the passage of 

seed particles through the measurement volume. It is noted that the range should be set 

for the larger of the two signals as both channels will have the same range.

LV Channel n Label – [Text/Value Entry Field]: Identifies a particular digitizer channel. 

These are required to be incremental numbers starting with 0. The default settings of 0-3 

should never require adjustment.

Channel ON/OFF – [Button]: These control buttons are included for expansion with the 

intention that they will enable or disable the signal burst digitization of a given channel. 

NOTE: These controls are intended for future expansion should additional velocity 

components be added. Thus they should not require adjustment.

Sample Rate (Hz) – [Value Entry Field]: Defines the rate at which the input signal bursts 

are digitized up to a maximum of 1.0 GHz (default). This setting should be sufficient for 

most data acquisition applications, especially if a Bragg cell is used (It is recommended that 

the signals NOT be down-mixed).

LV Burst Record Length – [Value Entry Field]: Defines the number of samples to be 

obtained from a single signal burst. The sample begins when a Master Trigger, 

Figure C.9., initiates the acquisition of a single record. The use of the pre-triggering 

capabilities of the high-speed digitizers can insure that the entire signal burst is digitized. 

This is set using the Reference Pos. (%) control located on the Advanced HW Settings 

Panel (Figure D.2.). The default setting of 10240 samples per signal burst has proven to be 

adequate in both laboratory and wind tunnel testing, and should be sufficient for most 

scenarios. This record length will allow the Processing software to execute Fast Fourier 

transforms up to 8192 samples. 

Auxiliary Channel Analog Input

PXI-6120 Multifunction Data Acquisition Module

Figures C.20.

(Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17. (C.20.)) →

The controls and settings on this sub-panel define the functionality of the auxiliary 

channel analog inputs. The auxiliary channels are provided to conditionally sample 

external sensors based on the acquisition of each randomly arriving signal burst. 

Input Voltage Range (V p-p) – [Drop Down Menu]: Defines the peak-to-peak voltage range 

of the analog-to-digital converters in the multifunction module. The range setting should 

be selected so that maximum resolution can be realized without saturating the digitizers. 

It is noted that the range setting applies to all active channels. The default setting is 

2.0 volts peak-to-peak.

Appendix D.6
Channel n Label – [Text/Value Entry Field]: Assigns a name to a given auxiliary analog 

channel. These names should be chosen to reflect the sensor being sampled. The default 

settings are ai0 – ai3.

Channel ON/OFF – [Button]: These control buttons are used to activate / deactivate the 

auxiliary channels, and should be activated when sensor voltages are input. The default 

(recommended) setting is ON.

Data Storage Management

Figures C.21.

(Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17. (C.21.)) →

Primary Base Data Storage Path – [File Manager Entry]: Defines the data storage location 

on the DA/C computer hard drive. All signal burst ensembles, conditionally sampled data, 

along with ensemble Log files will be stored in this location. Sub-directories will be created 

identifying each data ensemble that will contain the Header and Trigger files along with 

the ensemble of the digitized signal bursts. Alternatively the user can click on the browse 

icon to the right of the string entry field to access a file manager which can then be used to 

select the desired drive/directory or type a new directory name using the file manager.

Secondary (Processing) Base Data Storage Path – [File Manager Entry]: Defines the data 

storage location on the Processing computer hard drive. All signal burst ensembles, 

conditionally sampled data, along with ensemble Log files will be stored in this location. 

Sub-directories will be created identifying each data ensemble that will contain the Header 

and Trigger files along with the ensemble of digitized signal bursts. These sub-directories 

will have their own sub-directories that will contain the processed results along with Log 

files of the processing cycle and convergence and histogram plots. It is noted that the hard 

drive must be mounted as a local drive on the DA/C computer. Even if real time signal/data 

processing is not used, the use of the Secondary storage location provides an automatic 

data backup function. The Secondary storage location should be on a different physical 

drive from the Primary storage location.

Save Primary? Save Secondary? - [Switch]: Enable or disable the storage of the data 

ensembles on the respective locations. It is recommended that these controls should 

remain set to the default YES state to insure that two copies of the data ensembles are 

always stored.

Filename Prefix Source – [Indicator Button]: Selects the source used to generate the prefix 

of the file name that uniquely identifies the acquired digitized signal burst records. The 

available options are:

Use Date/Time – when selected the file name prefix will be constructed using the 

date and time at which the data acquisition cycle was initiated, e.g. 

D100311T132114 represents October 3, 2011 at 1:21:14 pm. This is the default and 

recommended setting.

Appendix D.7
User Prefix – when selected the prefix will be constructed using the string defined 

by the user in the Data Filename Prefix control.

Data Filename Prefix – [Text/Value Entry Field]: Accepts the user defined text that will be 

the prefix of the files containing the acquired digitized signal burst records.

Initial Series Index Value – [Value Entry Field]: Defines the index of the first file name of 

a sequence of file names, each containing the acquired digitized signal burst records for the 

U- and V-components of a particle passing through the measurement volume. The default 

and recommended setting for this index is 0. (Control disabled – provided for future 

expansion).

Series Index Increment – [Value Entry Field]: Defines the increment between successive 

signal burst record file names. The default and recommended setting of this index 

increment is 1. (Control disabled – provided for future expansion).

Append Date To Store Path? - [Button]: If selected, this control appends the current date, 

e.g., 100311 as a sub-directory on the data storage paths. The default and recommended 

setting is YES.

Automatically Increment Index? – [Button]: If selected, this control will automatically 

increment the record file name index by the Series Index Increment setting. The default 

and recommended setting is YES. (Control disabled – provided for future expansion).

Save ASCII? – [Button]: Record the signal burst records in ASCII format. This control 

was used during the development of the Processing software to allow spreadsheet retrieval 

of the signal records. The size of the records and the associated lengthy time required to 

transfer and store the data makes its use impractical in flow field investigations. Thus this 

control has been disabled, but if necessary it can be reinstated via a recompile of the DA/C 

program. The conversion of the binary data to ASCII data can also be performed using the 

auxiliary program ConvertBinary2ASCII (Appendix E.9.) off-line. (Control disabled – 

provided for future expansion).

Save Binary? - [Button]: Record the signal burst records in binary format. This control is 

enabled permanently unless the DA/C program is recompiled with the ASCII storage 

option reinstated, thus this Button should always be activated. (Control disabled – 

provided for future expansion).

User Comment – [Text/Value Entry Field]: Enter notes, comments or other information 

pertinent to the investigation being conducted. For example: 1.0-micron polystyrene 

particles in a 50/50 ethanol/water solution used to seed the flow. Ultrasonic generators 

used. The comment will be saved within each ensemble Header (.hed) file.

Appendix D.8
LV Data Acquisition Management

Figures C.22.

(Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17. (C.22.)) →

# Records to Acquire – [Value Entry Field]: Defines the number of signal burst records to 

be contained within an acquisition ensemble.

Delay Time Between Samples (milliseconds) – [Value Entry Field]: Defines a delay that is 

to be inserted between successive signal burst captures. This control is intended for the 

implementation of variable instrument reset time to insure flow independence of 

successive signal bursts. The function would only be implemented in extremely slow flows 

as the normal reset time of the PXI-5152 digitizer insures independence of successive 

signal bursts in the velocity ranges of interest. Thus the default and recommended setting 

is 0.

# Records/Scan Location – [Value Entry Field]: When operating with automated scanning 

of the input measurement volume location grid, this control sets the number of ensembles 

to be collected at a given spatial location (grid point) before proceeding to the next grid 

point. This parameter is to support advance future applications and is thus currently 

disabled. (Control disabled – provided for future expansion).

Acquisition Timeout (Sec) – [Value Entry Field]: Defines the time allocated for the 

acquisition of a data ensemble. If the specified number of signal bursts have not been 

captured before the timeout value is reached, a non-fatal Acquisition Timeout condition 

occurs which then closes the data ensemble, stores any acquired samples and returns 

control for the next command.

Auto Advance Scan Rig? – [Button]: Enables automatic testing where the measurement 

volume is sequenced through the spatial locations given in the grid file. Once a data 

ensemble has been acquired at a given location, the program automatically moves the 

measurement volume to the next spatial location (grid point). This control is currently 

disabled because the system is not yet set for production testing.

Acquisition Mode – [Drop Down Menu]: Controls the manner in which data records are 

acquired. The control is currently disabled, but will be activated during future expansion. 

The control, when activated, will provide the user with a degree of flexibility for verifying 

system operation and functionality. Three acquisition modes will be possible:

Continuous – In this mode of operation, signal bursts would be captured, processed 

and displayed continuously until the user manually stops the sampling activity. This 

capability is intended to be used for verifying that the system is operating properly. 

It is noted that no data will be saved to permanent storage.

Appendix D.9
Automatic – This will be the default mode of operation where the user-defined 

number of samples is acquired, saved and processed. This mode is the current mode 

of operation by the Data Acquisition and Control program.

Manual – In this mode of operation, the user will be provided with the ability to arm 

the data acquisition hardware so that individual signal burst captures can be made 

as determined by the operator. For example this capability will be useful when the 

seeding particle plumes arrive at irregular rates.

Convergence Threshold (m/s) – [Value Entry Field]: When convergence validation is 

enabled, Figure C.8., the value entered in this control establishes the threshold for the 

statistical stationarity test, Appendix E.2.-3. If the statistical stationarity test results are 

larger than the threshold, a warning message will be displayed suggesting that another 

data ensemble be acquired at this location. If another ensemble is acquired, both 

ensembles will be processed as a single ensemble and the test applied again. This can 

continue until the ensemble reaches 10,000 signal bursts at which point no further data 

can be gathered.

Reset Data Ensemble Plot Axis – [Drop Down Menu]: The Running Display program 

provides profile plots of the mean and standard deviation of the U- and V-component 

velocities, velocity magnitude, and flow angle as the measurement volume is traversed 

within the flow field. These plots are updated with each new measurement ensemble 

obtained at additional locations along the traverse. When a new traverse is begun by 

moving the measurement volume along a different axis, the plots are cleared and the 

profile plots begun anew. The axis that is the control to reset the profile plots is selected by 

the Drop Down Menu activated by the Reset Data Ensemble Plot Axis control.

Data Acquisition Conditions

Figure C.23.

(Figures C.13. (C.16.) [CONFIGURE SYSTEM] C.17. (C.23.)) →

Temperature (C) – [Value Entry Field]: Enter the current environmental temperature in 

degrees C.

Atm. Press (in. Hg) – [Value Entry Field]: Enter the current atmospheric pressure in 

inches of Mercury.

Particle Size (microns) – [Value Entry Field]: Enter the diameter of the seeding particles 

in microns. The default particle size is 1.0 micron. Note this control assumes that monodisperse particles are used.

Particle Type – [Text/Value Entry Field]: Input the type of seeding material used during 

the flow field investigation. The default is polystyrene. 

Appendix D.10
Control Scan Rig

Data Acquisition and Control Program

Configuration/Management Panel

Figure C.24.

(Figures C.13. (C.16.) [CONTROL SCAN RIG] C.24.) →

Scan Rig Functions

Figure C.25.

(Figures C.13. (C.16.) [CONTROL SCAN RIG] C.24. (C.25.)) →

Initialize Scan Rig – [Button]: Establish the GPIB control/data connection with the scan 

rig. The scan rig is also initialized. This must be the first control executed when the scan 

rig is to be used during the flow field investigation. Note that upon successful 

initialization of the GPIB connection and the MC4 scan rig, the GPIB Status Indicator will 

change its color from red (ERROR) to green (OK), and the Scan Rig Status indicator from 

red (OFF LINE) to green (ON LINE), Figure C.24.

Create Scan Grid File – [Button]: Display the Scanner Position Generator, Figure C.26. 

This tabbed screen provides the user with the tools to create a grid map that can be used, 

either manually or automatically, to move the measurement volume to the desired spatial 

locations within the flow field. The controls are outlined briefly below, greater detail will 

be presented in the Sub-Task Section:

Axis Settings – [Button & Value Entry Field]: Spatial units of inches or counts may 

be selected, number of units per grid increment, and starting location.

# Scan Indices – [Value Entry Field]: Number of spatial nodes for each axis.

Travel Per Step – [Value Entry Field]: Distance, in inches, of a single stepping 

motor increment.

Scan File Title – [Text/Value Entry Field]: File name of the generated grid file.

Scan File Comment – [Text/Value Entry Field]: Descriptive comment regarding the 

generated grid file, stored as a header in the grid file.

Scan Rig ID – [Text Entry Field]: Name of the scan rig controller.

Tabs:

Active Grid – Displays the grid currently being developed.

Complete Grid – Displays the complete grid that was generated.

Appendix D.11
Information – Displays information about the Complete Grid.

Control Buttons:

Generate Scan Data – [Button]: Compute the grid based on the parameters as 

defined on the Settings tab.

Import Existing Scan File – [Button]: Launches a file manager that can be 

used to read the grid from an existing file created by the grid generator and 

previously saved to a file.

Import Scan Data From File – [Button]: Launches a file manager that can be 

used to read a tab-delimited text file created by a spreadsheet program such 

as Microsoft Excel.

Append to Final Grid – [Button]: Appends a generated grid (Active Grid) or 

imported data grid to the data in the Complete Grid.

Save Scan Data to File – [Button]: Store the Complete Grid to a file.

Quit – [Button]: Terminate the Scanner Position Generator.

Load Scan Position File – [Button]: Opens a file manager to allow the user to select an 

ASCII file containing a table of coordinates that will be used to sequentially move the 

measurement volume to each spatial location. The coordinates obtained from this file are 

loaded into the table shown in the indicator labeled Automated Scan Rig Position Data, 

Figure C.24., along with being stored in the table that is displayed by the Scan File Data 

tab.

Get Scan Rig Status – [Button]: Returns the status information from the Klinger MC4 and 

displays it in the Klinger MC4 Scan Rig Status Display, Figure C.27. This display 

duplicates the information shown on the front panel display of the MC4 controller. This 

Control becomes active once the scan rig is brought on-line.

Scan Forward One Index – [Button]: Translates the measurement volume to the 

coordinates listed next in the table presented in the Automated Scan Rig Position Data, 

(example Scan Locations table shown in Figure C.24.). This Control becomes active once a 

scan position file has been selected and loaded.

Scan Back One Index – [Button]: Translates the measurement volume to the coordinates 

listed previously in the table presented in the Automated Scan Rig Position Data, 

Figure C.24. This Control becomes active once a scan position file has been selected, 

loaded, and at least one scan index has been executed.

Appendix D.12
Scan To Index – [Button]: Moves the measurement volume to the coordinates listed at the 

selected index as shown in the table presented in the Automated Scan Rig Position Data, 

(example Scan Locations table shown in Figure C.24.), and maintained in the internal table 

that can be viewed by selecting the Scan File Data tab. The Control opens the Set Scan 

Rig Index dialog [Value Entry Field], Figure C.28., where the user can input the index of 

the desired spatial location. This Control becomes active once a scan position file has been 

selected and loaded.

Take Scan Rig Offline – [Button]: Disconnects the scan rig from program control by 

closing the previously established GPIB connection. This Control becomes active once the 

scan rig is on-line.

Klinger MC4 Scan Rig Status Display

Figure C.27.

(Figures C.13. (C.16.) [CONTROL SCAN RIG] C.24. (C.27.)) →

Axis Information – [Display]: These four indicators display status information for each of 

the four axes, W, X, Y, and Z. Each indicator displays the current position of the axis in 

counts as well as Limit function indicators. These displays are updated after each scan is 

completed.

GPIB Status – [Indicator]: Indicates the status of the GPIB communications channel. 

When a successful connection has been established, the display changes color to green and 

shows the OK message. If the connection is uninitialized or has generated an error 

condition, the indicator becomes red and displays ERROR.

Scan Rig Status – [Indicator]: Indicates whether the scan rig is on-line. When the GPIB 

connection is established and the scan rig has been initialized, this display will be green 

and shows the ON LINE message. When the scan rig is not ready for use, the indicator is 

red and displays the OFF LINE message.

Input Bit Status – [Indicator]: Displays the state of the MC4 input status bits. When TTL 

low, these lights will be dark green to indicate LOW. When TTL high these lights will be 

bright green to indicate HIGH. These status bits have not been implemented at present.

Klinger MC4 Scan Rig Control Panel

Figure C.29.

(Figures C.13. (C.16.) [CONTROL SCAN RIG] C.24. (C.29.)) →

MC4 GPIB Address – [Value Entry Field]: Displays the GPIB address of the MC4 scan rig 

controller. The default setting is 6.

GPIB Controller Address – [Value Entry Field]: Displays the address of the GPIB interface 

used by the DA/C computer. The default setting is 0.

Appendix D.13
NOTE: Failure to set these two addresses will prohibit connection between the computer 

and the scan rig controller. 

MC4 GPIB Terminator (Write) – [Drop Down Menu]: Defines the character sequence that 

is used to terminate command strings issued to the MC4 controller through the GPIB 

interface. The default setting for the MC4 controller is CR & EOI (Carriage Return and 

End-or-Identify) and should never require adjustment. Additional options are provided to 

support future devices.

Step Size – Inches – [Value Entry Field]: Displays the distance traveled in inches for each 

count of the MC4 scan rig. The default setting of 38.37 micro-inches corresponds to the 

1-micron slides used in the MC4 system.

Axis Enabled? – [Switch]: The four controls, (W, X, Y, and Z axes), provide a lock on their 

respective scan axis so that the locked axes cannot be moved during a scan even if the 

coordinates of the locked axes change in the grid map. For example if the investigation 

mandates that only the X and Y axes will be used to position the measurement volume, the 

user should lock out the W and Z axes to prevent them from being accidentally moved 

should the grid map indicate otherwise or a manual command is attempted through the 

MC4 front panel.

Axis Select – [Buttons]: Selects the axis to be activated for a given manual operation. The 

All Axis control applies the next command to all axes. The All Axis control is useful when 

applying the Scan Rate and Acceleration Ramp commands.

Scanner Operation – [Buttons]: Defines the operation that is to be performed on the 

selected Axis using the settings found to the right of these buttons. The five available 

operations are:

a) Scan Axis – Moves the active axis the number of steps defined by the Step Size 

rotary control or input display;

b) Scan Rate – Sets the rate at which the selected axis is to be moved when active by 

the Scan Rate rotary control or input display;

c) Acceleration Ramp – Sets the acceleration ramp for the selected axis by the 

Acceleration Ramp rotary control or input display;

d) Seek Origin – Moves the selected axis to its origin; and,

e) Reset Axis – Resets the count value of the selected axis to 0.

Scan Direction – [Switch]: This switch defines the direction that the selected axis will be 

scanned.

Scan Mode – [Switch]: Defines the mode that will be used when the selected axis is moved. 

In Relative mode, the move will be in the selected direction and step size counts from the 

current position. In Absolute mode the move will be in the selected direction and step size 

Appendix D.14
counts from the zero count reference position that is defined as the position of a given axis 

at the time that the MC4 scan rig controller is first power on.

Note: The values set for the following three controls are applied to the active axis or all 

axes. The value desired by the user can be set either by turning the knob (value will be 

displayed in the text box) or by manually entering the value in the text box below the knob.

Step Size (Counts) – [Rotary / Value Entry Field]: Defines the number of steps (counts) 

that the active axis will be moved when the user activates the Scan Axis control.

Scan Rate – [Rotary / Value Entry Field]: Defines the stepping rate for the active axis in 

steps/second. The range of values is 32 to 4000 steps per second.

Acceleration Ramp – [Rotary / Value Entry field]: Defines the time it takes for the selected 

ramp to accelerate from 50 Hz to 4000 Hz in seconds. When setting this parameter the 

user should consider the weight residing on a given axis. The ramp speed should be slower 

for heavy item moves as attempting to accelerate too fast will cause the axis to bind.

MC4 Scan Rig Position Info – Inches 

Figures C.30.

(Figures C.13. (C.16.) [CONTROL SCAN RIG] C.24. (C.30.)) →

[Display]: Displays the current position of the four scan rig axes in inches. The position 

indicated refers to the absolute position of the axis from the MC4 origin which is the 

position of the axis at the time that power is first applied to the scan rig controller.

MC4 Scan Rig Position Info – Meters 

Figures C.31.

(Figures C.13. (C.16.) [CONTROL SCAN RIG] C.24. (C.31.)) →

[Display]: Displays the current position of the four scan rig axes in meters. The position 

indicated refers to the absolute position of the axis from the MC4 origin which is the 

position of the axis at the time that power is first applied to the scan rig controller.

Acquire Data

Data Acquisition and Control Program

Configuration/Management Panel

Figure C.32.

(Figures C.13. (C.16.) [ACQUIRE DATA] C.32.) →

Selection of the Acquire Data navigation button presents the user with the display shown 

in Figure C.32. As can be seen, this panel provides controls for the data acquisition process 

as well as feedback regarding the data collection activity.

Appendix D.15
Data Acquisition Controls

Figure C.34.

(Figures C.13. (C.16.) [ACQUIRE DATA] C.32. (C.34.)) →

Start Data Acquisition – [Button]: Initiates the data acquisition process, which once 

started, continues until: a) the requested number of signal bursts have been acquired; 

b) the specified timeout limit is reached; or, c) the operator activates the Terminate Data 

Acquisition button. Multiple operations are performed prior to, during and after data 

acquisition has been initiated:

a) Data acquisition hardware configuration /initialization/management;

b) Software parameter configuration/initialization/management;

c) Operation(s) sequencing;

d) File system management;

e) Synthetic signal management (Rotor Encoder Simulator, Synthetic Signal Burst 

Generator);

f) System progress monitoring;

g) Status information calculation/presentation;

h) Data retrieval/archival/presentation;

i) Data processing triggering; and,

j) Log file management.

Terminate Data Acquisition – [Button]: Halts the current data acquisition cycle 

immediately. All of the in-process operations are gracefully halted and all acquired signal 

bursts are archived to disk prior to returning program control to the user.

Data Ensemble Plot Options – [Button]: Defines data ensemble processing and results 

display control. All data plots are presented on the Processing computer. The three 

options are:

New – The current data ensemble marks the start of a new sequence of related data 

points. The current data ensemble is processed and the statistical stationarity 

convergence plots, and histogram plots reflect the results of processing the current 

data ensemble. The running U- and V-component, velocity magnitude and flow 

angle mean and standard deviation plots are cleared. New running plots will begin 

when the data ensemble for the next location is acquired and processed.

Continue – The current data ensemble is processed and the statistical stationarity 

convergence plots, and histogram plots reflect the results of processing the current 

data ensemble. The running plots are updated with the results.

Repeat – The current data ensemble is combined with the previously acquired 

ensemble(s) obtained at the current measurement volume location. The combined 

ensembles are processed as a single ensemble, and the statistical stationarity 

convergence plots and histogram plots reflect the results from the combined 

Appendix D.16
ensembles. The running plots are updated with the results from the combined 

ensembles, replacing the previously obtained results for that location.

Data Acquisition Information

Figure C.34.

(Figures C.13. (C.16.) [ACQUIRE DATA] C.32. (C.34.)) →

Data Acquisition Start Time – [Display]: Presents the date and time when the current 

data acquisition cycle was initiated.

Current Date & Time – [Display]: Presents the current date and time-of-day.

Current Data Set – [Display]: Presents the sub-directory name of the current data 

ensemble (same as the root portion of the digitized signal burst file names), Figures C.17 

and C.21.

# Records Acquired – [Display]: Presents the real-time count of signal bursts acquired 

during the current data acquisition cycle.

Elapsed Time – [Display]: Presents the elapsed time of the current data acquisition cycle 

in Hours:Minutes:Seconds:Hundredths format.

LV Data Rate (Hz) – [Display]: Presents the rate at which signal bursts are being acquired 

(# Records Acquired / Elapsed Time) for the current data acquisition cycle.

Data Acquisition Progress - % – [Display]: Graphically presents the percentage of the 

current data acquisition cycle that has been completed based on the number of signal 

bursts acquired versus the number requested.

Data Transfer/Storage Progress - % – [Display]: Graphically presents the percentage of the 

number of data records retrieved from the PXI-5152 digitizer versus the total number of 

signal bursts acquired during the current data acquisition cycle. It is noted that transfer of 

the data records to the computer hard drives cannot be monitored as this function is 

executed by the LV Data Manager DLL, which does not provide real-time feedback to the 

DA/C program. 

System Settings

Figure C.34.

(Figures C.13. (C.16.) [ACQUIRE DATA] C.32. (C.34.)) →

Rotor Encoder Sampling – [Display]: Presents the status of the conditional sampling of 

the rotor shaft encoder.

Rotor Position Encoder Source – [Display]: Presents the source of the rotor shaft encoder. 

The display of ACTUAL indicates that the sampled pulse train is from the shaft encoder 

Appendix D.17
attached to the rotor. The display of SIMULATED indicates that the sampled pulse train 

originates from the internal shaft encoder simulator, Figure C.18.

Scan Rig Status – [Display]: Shows whether or not the scan rig has been activated, on-line 

and ready for use, Figure C.27.

LV Burst Signal Source – [Display]: Presents the source of the signal bursts to be 

measured. The display of ACTUAL indicates that the signal bursts originate from the 

laser velocimeter photomultipliers. The display of SIMULATED indicates that the signal 

bursts originate from the Arbitrary Waveform Generator. Typically the waveforms being 

converted to electronic signals by the AWG originate from the Monte Carlo Laser 

Velocimeter Simulation program. However, the AWG may also be driven by actual signal 

bursts captured by the laser velocimeter in the laboratory or from a flow field 

investigation.

Data Acquisition Panel – Current Results Tab

Figure C.32.

(Figures C.13. (C.16.) [ACQUIRE DATA] C.32. [ → Current Results Tab])

When a data acquisition operation has been completed, the acquired data sets are written 

to hard disk drives located in the Data Acquisition computer and to the networked 

Signal/Data Processing computer. Once the data ensemble has been written to the 

networked computer, the Data Acquisition program updates the trigger file on the 

Signal/Data Processing computer with the parameters needed to process the ensemble. 

Closing the trigger file alerts the Signal/Data Processing program to read the parameters 

and begin processing the ensemble. When processing is completed, the program then 

updates the return file, which when closed, alerts the Data Acquisition program to upload 

the statistical parameters obtained from the ensemble, and to present them to the user on 

the Current Results tab, Figure C.32. That is, if the Enable Online Processing and 

Enable Convergence Validation options (Figures C.13 (C.17. (C.18.))) are enabled. This 

tab contains nine displays presenting the results of the most recent data 

acquisition/processing sequence, and is automatically updated each data 

acquisition/processing cycle. The following displays are presented:

U- and V-component Velocity Histograms – [Display]: Presents the histograms of U- and 

V-component ensemble velocities in meters-per-second.

U- and V-component Mean Velocity Convergence – [Display]: Presents plots of the 

convergence of the U- and V-component mean velocities for the current data ensemble in 

meters-per-second as a function of cumulative blocks of 100 measurements, i.e., first 100, 

first 200, first 300, etc. 

U- and V-component Standard Deviation Convergence – [Display]: Presents plots of the 

convergence of the U- and V-component velocity standard deviations for the current data 

Appendix D.18
ensemble in meters-per-second as a function of cumulative blocks of 100 measurements, 

i.e., first 100, first 200, first 300, etc.

Velocity Magnitude Histogram – [Display]: Presents the histogram of the resolved velocity 

magnitude in meters-per-second using the current data ensemble.

Flow Angle (Alpha) Histogram – [Display]: Presents the histogram of the resolved flow 

angle in the vertical plane in degrees using the current data ensemble.

Rotor Azimuth Position Histogram – [Display]: Presents the histogram of conditionally 

sampled shaft encoder angles (0-1023 counts) based on the random arrivals of signal bursts 

contained in the current data ensemble. This histogram plot is displayed when the Enable 

Rotor Sampling option is enabled, Figures C.17. and C.18.

Data Acquisition Panel – Cumulative Results Tab

Figure C.33.

(Figures C.13. (C.16.) [ACQUIRE DATA] C.32. [ → Cumulative Results Tab] C.33.) →

The Cumulative Results tab, Figure C.33., of the Data Acquisition Management 

Control Interface, Figure C.32., presents resolved flow-related quantities accumulated 

during a sequence of data acquisition/processing cycles that have occurred as the 

measurement volume is translated to a series of spatial locations. These plots are updated 

automatically following each new data acquisition/processing cycle. The Enable Online 

Processing and Enable Convergence Validation options, Figures C.17. and C.18., must be 

enabled to activate these plots. The following plots are presented:

U- and V-component Mean Velocity Profiles (Non-Coincidence) – [Display]: Presents the 

mean velocity profiles along the measurement volume scan sequence without imposing the 

requirement of coincident U- and V-component measurements. The velocity profiles, in 

meters-per-second, are plotted versus either measurement volume position in meters, or 

sequence number.

U- and V-component Mean Velocity Profiles (Coincidence) – [Display]: Presents the mean 

velocity profiles along the measurement volume scan sequence with the requirement of 

coincident U- and V-component measurements. The velocity profiles, in meters-persecond, are plotted versus either measurement volume position in meters, or sequence 

number.

Mean Velocity Magnitude Profile – [Display]: Presents the mean velocity profile along the 

measurement volume scan sequence (derived from coincident U- and V-component 

measurements). The velocity profile, in meters-per-second, is plotted versus either 

measurement volume position in meters, or sequence number.

Mean Flow Angle (Alpha) Profile – [Display]: Presents the mean vertical flow angle profile 

along the measurement volume scan sequence (derived from coincident U- and 

Appendix D.19
V-component measurements). The flow angle profile, in degrees, is plotted versus either 

measurement volume position in meters, or sequence number.

Reynolds Stress Profile – [Display]: Presents the Reynolds stress profile along the 

measurement volume scan sequence (derived from coincident U- and V-component 

measurements). The Reynolds stress profile ( ρu ' v ' ), in kg/m/s2

, is plotted with only the 

velocity contributions ( u ' v ' ) in m2/s2 versus either measurement volume position in 

meters, or sequence number.

System Diagnostics

Data Acquisition and Control Program

Configuration/Management Panel

Figure C.38.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38.) →

Selection of the System Diagnostics navigation button presents the user with the Data 

Acquisition Diagnostic Information Panel shown in Figure C.38. This panel contains a tabbased interface with settings and feedback/status elements related to the data acquisition 

process. The information presented in the various tabs provides insight into system 

operation along with the acquired data, but have no control capabilities.

Data Acquisition Diagnostics Information Panel

Acquired Data Tab

(All Fields Are Display Only)

Figure C.38.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Acquired Data Tab])

This sub-panel presents the data obtained during the most recent data acquisition 

sequence. The data is presented in both graphical and numerical format. This data is in 

raw or unprocessed format and is intended for diagnostics purposes to give the user a 

degree of confidence that the system is operating properly. It should be noted that 

graphical data is presented only when the user activates the Plot Data? Option, 

Figure C.38. (C.39.).

Plot Data? - [Button]: When this control is enabled (ON), Figure C.39., the acquired 

digitized signal bursts are presented on the U-Component Data and V-Component Data 

displays. Typically this operation is used only for diagnostic purposes since the plots 

greatly increases the time required for a data acquisition cycle. Thus, unless verification of 

the acquisition of the signal bursts is needed, it is recommended that this control should 

be disabled (OFF) during a flow field investigation.

Plot Delay (ms) – [Value Entry]: This control, Figure C.39., specifies the length of time in 

milliseconds that each digitized signal burst is displayed when the Plot Data? Option is 

enabled.

Appendix D.20
U-Component Data & V-Component Data – [Display]: These displays present the digitized 

signal burst voltage waveforms for these velocity components. The Plot Data? Option 

must be enabled.

Auxiliary Channel Analog Data Plot – [Display]: Presents the time history of the four 

conditionally sampled analog signals as acquired by the Auxiliary channels, Figure C.17., 

((Figures C.13. (C.17. (C.20.))).

Rotor Azimuth Position Time History – [Display]: Presents the time history of the 

conditionally sampled shaft encoder azimuth (0-1023 counts). The time history is 

presented following the completion of the current data acquisition cycle. The Enable 

Rotor Encoder Sampling Option must be enabled, Figure C.18., ((Figures C.13. (C.17. 

(C.18.))).

Raw Acquired Data – [Display]: Displays the diagnostic characteristics of the current data 

ensemble. These monitors include voltage measurements for the signal burst ensemble 

and the auxiliary channel analog signals, interarrival times between bursts in seconds, and 

rotor azimuth position in encoder counts. This information is in raw format, before 

signal/data processing has been conducted.

Data Acquisition Diagnostics Information Panel

Hardware Tab

(All Fields Are Display Only)

Figure C.40.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Hardware Tab] C.40.) →

This sub-panel displays the configuration of the Data Acquisition hardware as defined by 

the user and internal settings established within the control software. The sub-panels are 

group characteristics according to the device or function. This panel only displays the 

information, no settings can be changed.

LV Burst Signal Digitizer (PXI-5152) Configuration

High-Speed Analog-to-Digital Converter

Figure C.40.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Hardware Tab] C.40.) →

General Section

Resources – Identifies the device name as it is specified in the NI-MAX microcode. 

Channel Name(s) – Lists the names of the digitizer channels available on the 

PXI-5152 digitizer.

Appendix D.21
Channel Section

Bandwidth – Presents the bandwidth of the digitizer input channels expressed as the 

frequency at which the circuitry attenuates the input signal by 3 dB. The value 0 

indicates the default value of the PXI-5152 which is 340 MHz at an input impedance 

of 50 ohms and 300 MHz at an input impedance of 1 Mega ohm.

Input Impedance – Presents the input impedance setting for the PXI-5152. The 

impedance is set to 1 Mega ohm for laser velocimeter data acquisition applications 

because the triggering Scope, Figure C.9., is set to 50 ohms to match the impedance 

of the cable transferring the signals from the current-source photomultipliers.

Horizontal Section

Record Length – Presents the number of samples that will be acquired by the 

digitizers once triggered by the Scope and validated by the LVTG (Master Trigger), 

Figure C.19., (Figures C.13. (C.17. (C.19.))).

Sample Rate – Presents the rate in Hertz at which the input signal bursts are 

digitized. The maximum (default) sample rate for the PXI-5152 digitizer is 1.0 GHz.

Vertical Section

Input Voltage Range (V p-p) – Presents the input voltage range setting in volts. The 

available settings are 0.1- to 10.0-volts in a 1, 2, 4, 10 sequence.

Vertical Offset – Presents the voltage offset to be applied to the input signal bursts 

in volts. If the signal bursts originate from the TSI optical system, the pedestal 

voltage has been removed, thus the offset should be set to 0 volts (default). If the 

signal bursts originate directly from the photomultipliers, the offset should be set to 

the peak voltage of the voltage range selected (assuming the negative signals 

normally produced by current-source photomultipliers) to provide full-scale 

digitization.

Probe Atten. – Presents the attenuation (scale) factor applied to the input signal 

burst. This would be set, for example to 10.0 if a 10X probe was used. For laser 

velocimetry applications, the value would be 1.0 (default) since there is no 

attenuation by the 50-ohm coaxial cable used to transmit the signal bursts from the 

photomultiplier to the digitizer.

Vertical Coupling – Presents the coupling setting for the input photomultiplier 

signals. The available options are DC, AC and GND. DC coupling (default) passes 

both AC and DC signals whereas AC blocks offset voltages, thus passing only the AC 

portion of the signal. GND grounds the digitizer inputs.

Appendix D.22
Trigger Settings Section

Trigger Mode – Presents the manner in which the digitizer (PXI-5152) is to be 

triggered to initiate the digitization of the input signal. The available options are 

Immediate, Software, Digital, Analog Signal or External Trigger Edge (default), or 

Window.

Trigger Source – Identifies the source of the trigger signal that will initiate signal 

digitization. The available options are Channel 0, Channel 1, or External Trigger. 

The display should show Ext. Trigger as the Master Trigger is generated by the 

LVTG, Figure C.9.

Trigger Slope – Identifies the slope of the trigger signal that will initiate signal 

digitization. The available options are Positive and Negative. The display should 

indicate a Negative slope based on the Master Trigger generated by the LVTG, 

Figure C.9.

Trigger Coupling – Identifies the coupling applied to the trigger signal. The possible 

options are AC, DC, HF Reject, LF Reject, AC Plus HF Reject. The AC and DC 

coupling options are identical to the manner that they are applied for the Vertical

Coupling setting. The HF Reject setting is similar to DC coupling except that higher 

frequencies (typically >20 kHz) are rejected. The LF Reject setting is similar to AC 

coupling except the low frequency cutoff is higher (~200 kHz). AC Plus HF Reject 

setting combines the AC and HF Reject capabilities. Based on the characteristics of 

the Master Trigger generated by the LVTG, DC coupling should be used.

Trigger Level – Presents the triggering threshold, that once exceeded by the trigger 

pulse, the PXI-5152 will initiate digitization of the input signal. Based on the 

characteristics of the Master Trigger generated by the LVTG, this is typically 

1.0 volt.

Digital Trigger Delay – Presents the delay, 0- to 10.0-seconds, between the 

acceptance of the trigger and the initiation of signal digitization in the Digital and 

Software Trigger modes of operation. The laser velocimeter application does not 

require a delay, thus the setting should be 0.0 seconds.

Trigger Timeout (s) – Defines the amount of time to wait after the triggering criteria 

has been satisfied to allow for the data digitizing process to complete before 

generating an error. The laser velocimeter application does not require a timeout, 

thus the value should be set to 0.00 so that system control is returned to the 

application immediately. This places the burden of verifying the completion of the 

signal burst digitization on the application which uses other mechanisms to verify 

that the data acquisition criteria has been satisfied. Proceeding in this manner 

allows the DA/C program to monitor the arrival of signal bursts to the digitizer.

Appendix D.23
Trigger Holdoff – Defines the amount of time in seconds after the triggering criteria 

has been satisfied before the digitizer can be triggered again (typically referred to as 

dead time in laser velocimetry applications). The hold-off is set to 0.0 seconds to 

obtain minimum dead time. The inherent dead time in the electronics typically 

exceeds the integral time scale of the flow, thus each signal burst measurement is 

independent, in a flow turbulence sense, from its neighbors.

Analog Trigger Delay – Presents the delay, 0- to 10.0-seconds, between the 

acceptance of the trigger and the initiation of signal digitization in the Analog, 

External, or Window Trigger modes of operation. The laser velocimeter application 

does not require a delay, thus the setting should be 0.0 seconds.

Hysteresis – When the Analog Hysteresis Ref Trigger mode is used, this parameter 

specifies the size of the hysteresis window on either side of the trigger level in volts. 

The digitizer triggers when the trigger signal crosses through the hysteresis value 

specified with this parameter. This parameter is not used for laser velocimetry 

applications. The default is set to the nominal value of 0.05 volts.

Low Level – When the Window Trigger mode is selected, this parameter specifies the 

lower voltage threshold of the triggering signal used by the digitizer. This parameter 

is not used for laser velocimetry applications. The default setting is 0.0 volts.

High Level – When the Window Trigger mode is selected, this parameter specifies 

the upper voltage threshold of the triggering signal used by the digitizer. This 

parameter is not used for laser velocimetry applications. The default setting is 

0.1 volts.

Reference Pos. (%) – Specifies the number of pre-trigger versus post-trigger points 

that are stored. The reference position is expressed as a percentage of the complete 

record, from 0 to 100, as defined by the Record Length setting, Figure C.19., 

(Figures C.13. (C.17. (C.19.))). A value of 40% is the default and recommended 

setting. This means that 40% of the points saved in the data record occurred prior 

to the trigger criteria being satisfied. This pre-trigger capability is used in laser 

velocimetry to allow triggering to be set near the peak of the signal burst, yet the 

digitizer will capture the entire signal burst. This method effectively shrinks the 

measurement volume by allowing only particles passing through the center of the 

measurement volume to be accepted. Also this helps insure that only signal bursts 

with the highest signal-to-noise ratio will trigger acquisition. This parameter is set 

in the Advanced HW Settings dialog, Figure D.2., (Figures C.13. (C.17. (C.18. (D.1.))) 

[Advanced HW Settings] D.2.). →

Window Mode – When window triggering mode is used, this parameter indicates 

whether the trigger is generated when the incoming signal satisfies the trigger 

criteria entering or leaving the window.

Appendix D.24
Analog Auxiliary Signal Digitizer (PXI-6120) Configuration

Multifunction Data Acquisition Module

Figure C.40.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Hardware Tab] C.40.) →

6120 Analog Input Channels – Identifies the device names of the input channels as 

specified in NI-MAX (LVMultiFunc) microcode.

Channel Labels – Displays the unique names of the analog input channels of the PXI-6120. 

The default names are consecutive labels ai0 – ai3, and are normally not changed for laser 

velocimeter applications.

Input Voltage Range (V) – Displays the input voltage range settings of the analog input 

channels. The available ranges are ±0.2-, ±0.5-, ±1.0-, ±2.0-, ±5.0-, ±10.0-, ±20.0- and 

±42.0-volts. The default setting is ±2.0 volts.

Record Length – Displays the length of the data acquisition record. Since the analog input 

channels are used exclusively as conditionally sampled channels in laser velocimetry 

applications, there is only one measurement taken per Master Trigger event. Thus the 

record length setting is set to 0.

Sample Rate – Displays the rate at which the analog input channels are sampled. Since the 

analog input channels are used exclusively as conditionally sampled channels in laser 

velocimetry applications, there is only one measurement taken per trigger event. Thus 

sample rate has no meaning for laser velocimetry applications.

Input Coupling – Displays the coupling setting for the input analog signals. The available 

options are DC, AC and GND. DC coupling (default) passes both DC and AC signals into 

the system while AC coupling passes only AC signals (any DC offset is stripped from the 

signal). GND grounds the digitizer inputs.

Input Terminal Configuration – Displays the input signal termination setting for the 

analog signals. The available settings are default (for the PXI-6120 this is RSE (Reference 

Single Ended)), Differential, NSRE (Non-Referenced Single Ended) and RSE (Reference 

Single Ended). Either the default or RSE setting is employed for laser velocimetry 

applications.

Trigger Source – Displays the source of the signal used to trigger the sampling of the signal 

applied at the four available analog input channels. The laser velocimeter configuration 

uses the signal derived from the Master Trigger from the LVTG, Figure C.9., routed to the 

PXI-6120 via the PXI backplane.

Analog Sample Clock Source – Displays the source of the clock signal used to initiate the 

digitization of the signals present at the inputs of the analog channels. As described above, 

Appendix D.25
the laser velocimetry application acquires only a single sample of the analog input signals 

when triggered. Thus the clock source is the same as the Trigger Source.

System Trigger Configuration

Figure C.40.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Hardware Tab] C.40.) →

Trigger Definition Section

Trigger Source Terminal – Identifies the source (hardware terminal) of the Start 

Acquisition Trigger. The laser velocimetry application uses the Reference Trigger 

derived from the Master Trigger from the LVTG, Figure C.9., routed to the PXI-6120 

via the PXI backplane.

System Trigger Terminal – Identifies the terminal where the Start Acquisition 

Trigger, required by other devices in the PXI chassis, can be obtained.

Trigger Name – Presents the label associated with the System Trigger signal.

Trigger Polarity – Sets the polarity of the System Trigger Signal. The non-inverted 

version of the trigger signal is employed for laser velocimetry.

Counter Generated Trigger Definition Section – This group of parameters is associated 

with the use of one of the counters within the PXI-6120 Multifunction module as the 

source for the trigger signals needed. The counter system can be used to verify system 

operation when neither signal bursts or synthetic signals produced by an Arbitrary 

Waveform Generator were available. This capability is maintained for diagnostic purposes 

only, and is not used during normal laser velocimetry applications.

Trigger Pulse Frequency (Hz) – Presents the rate at which the counter generated 

trigger pulses are to be generated in Hertz. The default value is 1 Hz.

Initial Delay – Presents the delay in seconds after the counter has been armed before 

the first trigger signal is generated.

Trigger Pulse Duty Cycle – Defines the duty cycle of the trigger pulse train.

Trigger Idle State – Defines the quiescent state of the trigger signal. Under most 

conditions this will be TTL Low.

Counter Enable – This button enables the counter circuitry of the PXI-6120 to be 

used for generating the trigger signals.

Appendix D.26
Trigger Signal Routing Section

Trigger Destination #1 & Trigger Destination #2 – The flexibility inherent in the 

PXI system provides the ability to route system signals using software commands to 

different hardware connectors on the various system devices. These settings reflect 

the destinations of the Reference trigger generated by the PXI-5152 digitizer. PXI 

Trigger Line 0/RTSI 0 reflects the routing of the Reference trigger signal to the PXI 

back plane making it available to other devices residing in the PXI chassis. PFI 1 

reflects the routing of the Reference trigger to the PFI 1 connector on the PXI-5152 

front panel.

Shaft Encoder Reader (PXI-6602) Configuration

Counter/Timer Module

Figure C.40.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Hardware Tab] C.40.) →

The PXI-6602 is a multipurpose counter/timer device capable of performing a number of 

pulse counting and timing operations. The device has been configured using hardware and 

software mechanisms for laser velocimetry applications. Specifically the counter/timer was 

set to perform the following functions:

One counter has been configured to operate in angular shaft encoder mode to record 

position information generated by a rotatory position encoder such as those installed 

on a rotorcraft model.

Three counters have been configured to simulate the output signals produced by a 

rotor shaft encoder mounted at the base of a helicopter shaft rotating at 2800 rpm. 

The resultant encoder circuitry simulates an encoder producing 1024/rev resolution 

and 1/rev (signifying the 0 azimuth position) digital pulse trains.

Azimuth Position Tracking Counter – Identifies the counter on the PXI-6602 channel that 

is configured to operate in angular shaft encoder mode and sample both the 1024/rev and 

1/rev pulse trains generated by the rotor shaft encoder.

Azimuth Position Sample Trigger Source – Identifies the hardware connection where the 

Master Trigger, that causes the Azimuth Position Tracking Counter to store its count 

value, is located. The Master Trigger, generated by the LVTG, enables the counter to 

record the rotor position, synchronized with the acquisition of the signal burst.

Azimuth Position Encoder Pulses Per Revolution – Identifies the number of pulses 

produced per revolution by the rotor shaft encoder.

Appendix D.27
Acquisition In Progress Indicator Control/Info

Figure C.40.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Hardware Tab] C.40.) →

One of the digital lines available on the PXI-6120 module is used as a System Busy line to 

indicate that a data acquisition cycle was currently in progress. The line is raised to a TTL 

High level at the start of the data acquisition cycle and remains in that state until: a) all of 

the requested signal bursts have been acquired; b) a timeout condition is reached; or c) the 

user has chosen to abort the data acquisition operation. At the completion of the data 

acquisition cycle, the line is returned to a TTL Low state. The System Busy line can be 

used to synchronize laser velocimeter data acquisition activities to external 

devices/systems.

Busy Digital Lines – Identifies the hardware connection where the System Busy signal can 

be obtained.

Busy TTL Line State – Indicates the state of the System Busy signal: lit Busy. →

LV Digitizer(s) (PXI-5152) Instrument Handles – Identifies the device names specified in 

NI-MAX for digitizers installed in the PXI chassis. NI-MAX provides the driver interface 

between the control software and the data acquisition hardware.

Auxiliary Board (PXI-6120) Task – Identifies the name of the task associated with the 

Analog data acquisition operations of the PXI-6120 channel.

ARB Trigger Task – Identifies the name of the task associated with generating a digital 

trigger pulse that is used to externally trigger the Arbitrary Waveform Generator used to 

generate synthetic signal bursts.

PXI-6602 Rotor Position Sampling Task – Identifies the name of the task associated with 

the counter elements of the PXI-6602 used to count encoder pulses produced by a rotor 

shaft encoder or the simulated shaft encoder.

Data Acquisition Busy Task – Identifies the name of the task associated with the Digital 

data lines used to generate the System Busy signal.

Data Acquisition Diagnostics Information Panel

Information Tab

(All Fields Are Display Only)

Figure C.41.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Information Tab] C.41.) →

The Information tab, Figure C.41., presents a variety of data acquisition information 

reported back from the system components rather than user settings (as shown on the 

Appendix D.28
Hardware tab of the Data Acquisition Diagnostics Information panel, ((Figures C.13. 

(C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Hardware Tab] C.40.) → ). The ability to 

retrieve and present this information provides confirmation that the system is configured 

according to the user's specifications. This panel only displays the information, no settings 

can be changed.

LV Burst Signal Digitizer (PXI-5152) Information

High-Speed Analog-to-Digital Converter

Figure C.41.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Information Tab] C.41.) →

Actual Sample Rate (PXI-5152) (Hz) – Specifies the sample rate used by the PXI-5152 

during the last completed data acquisition cycle.

Record Length – Specifies the number of samples requested by the operator for each 

acquired signal burst, Figure C.19., (Figures C.13. (C.17. (C.19.))).

Actual Record Length – Specifies the number of samples actually contained in each data 

record acquired during the last completed data acquisition cycle.

# Active Scope Input Chans. – Specifies the number of PXI-5152 digitizers available in the 

Data Acquisition system.

5152 Total Horizontal Memory Depth (Bytes) – Specifies the total on-board memory of the 

PXI-5152 in bytes. The PXI-5152 used in the Data Acquisition System has 512 Mb of onboard memory.

Total Available Samples/Ch (Mb) – Specifies the total number of samples available on each 

of the PXI-5152 digitizer's two channels in megabytes (Mb). The PXI-5152 used in the 

Data Acquisition System has 256 Mega Samples (MSamples) available for each of the two 

channels.

Sample Rate Setting (PXI-5152) – Specifies the sample rate requested by the user at the 

start of the data acquisition cycle.

LV Board 1 Status – Identifies the status of the first LV signal digitizer during the data 

acquisition activity. Note: A two component laser velocimeter only requires a single PXI5152 digitizer.

LV Board 2 Status – Identifies the status of the second LV signal digitizer during the data 

acquisition activity. Note: The second PXI-5152 digitizer is utilized for three component 

laser velocimeters.

Auxiliary Board Status – Identifies the status of the PXI-6120 Multifunction board 

(Auxiliary Data Channel) during the data acquisition activity.

Appendix D.29
Analog Auxiliary Signal Digitizer (PXI-6120) Information

Multifunction Data Acquisition Module

Figure C.41.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Information Tab] C.41.) →

Timebase Source – Specifies the source of the Master Timebase used on the PXI-6120 

Multifunction board.

Timebase Divisor – Specifies the number of Master Timebase pulses required to generate a 

single sample clock for the PXI-6120. This information is irrelevant for the current Data 

Acquisition System since the sample clock used is the Master Trigger signal which occurs 

at a random rate based on the Poisson arrival statistics of the seeding particles.

Max. Sample Rate – Indicates the maximum Sample Clock rate supported by the PXI-6120. 

This information is irrelevant for the current Data Acquisition System.

Output Buffer Size – Specifies the size of the on-board buffer allocated to store the number 

of samples requested by the user. The size of the buffer is controlled by the number of LV 

data samples requested by the user.

Per Analog Input Chan Mem. Depth (Mb) – Specifies the maximum possible number of 

samples that can be acquired on each of the four Analog Input channels in Mega bytes.

Total Input Mem. Size (Mb) – Specifies the total size of the on-board memory available on 

the PXI-6120.

Actual Sample Rate (PXI-6120) – Specifies the user setting for the sample rate of the 

PXI-6120. As the sample rate is dictated by the Master Trigger, this value is irrelevant for 

the Laser Velocimeter Data Acquisition System.

6120 Sampling Mode – Specifies the sampling mode of the PXI-6120. The mode should be 

Finite.

6120 Sampling Edge – Specifies the edge of the PXI-6120's sample clock on which the input 

signals are sampled. The edge should be Rising.

6120 Analog Input Buffer Size – Specifies the size of the on-board input sample buffer 

available for the Analog Input sampling task. The size of the buffer is controlled by the 

number of signal bursts requested by the operator.

# Auxiliary Chanel Samples Acquired – Indicates the number of samples acquired during 

the last completed data acquisition cycle.

Appendix D.30
6120 Start Trigger Source – Identifies the name of the terminal containing the Start Data 

Acquisition signal. The signal causes the PXI-6120 to begin performing its data acquisition 

operations. This signal is the Master Trigger.

6120 Sample Clock Source – Identifies the name of the terminal containing the PXI-6120 

Sample Clock Signal. This signal is the Master Trigger.

# Active Analog Input Channels – Specifies the number of available Analog Input 

Channels on the PXI-6120.

6120 Start Trigger Type – Specifies the type of signal that will be used to initiate the data 

sampling process on the PXI-6120. The type should be Digital Edge.

Data Acquisition Diagnostics Information Panel

Sub Task Info Tab

(All Fields Are Display Only)

Figure C.42.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Sub Task Info Tab] C.42.) →

The information presented on this tab, Figure C.42., pertains to the Laser Velocimeter 

Data Acquisition System software background tasks. The activation and use of these tasks 

is controlled by the underlying Data Acquisition and Control software and not the program 

operator. Some of these tasks are always used while others are used as needed. This panel 

only displays the information, no settings can be changed.

Data Storage Path Generation Task

Path Generator Task Status?

Figure C.42.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Sub Task Info Tab] C.42.) →

This is a background task which generates file paths from the Data Storage Management 

information entered by the user on the System Configuration panel, Figure C.21., 

(Figures C.13. (C.17. (C.21.))). The task is always launched at program start up as it 

facilitates the storage of the acquired data samples during the data acquisition activity.

Path Generator Task Status? – Indicates whether the Data Storage Path Generation task is 

enabled or disabled.

Shaft Encoder Simulation Task

1024/Rev Rotor Simulator Task Status?

Figure C.42.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Sub Task Info Tab] C.42.) →

This background task generates pulse trains that simulate the output signals originating 

from an azimuth encoder mounted to a rotating shaft. It is launched when the operator 

Appendix D.31
has selected the Enable 1024/Rev Simulator option on the System Configuration panel, 

Figure C.18., (Figures C.13. (C.17. (C.18.))).

1024/Rev Rotor Simulator Task Status? – Indicates whether the 1024/Rev Simulator task 

is enabled or disabled.

Oscilloscope Trigger Out Pulse Shaping Task

One Shot Generator Task Status?

Figure C.42.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Sub Task Info Tab] C.42.) →

This background task serves the purpose of managing the retriggerable one-shot pulse 

circuit configured on the PXI-6602 Counter/Timer board installed in the PXI chassis. A 

500 ns-long one shot pulse signal is generated each time an analog trigger output pulse is 

received from the signal burst triggering Oscilloscope. The task is always launched at 

program start up as it facilitates the generation of the Master Trigger by the LVTG.

One Shot Generator Task Status? – Indicates whether the One Shot task is enabled or 

disabled.

Signal Burst Simulation Manager Task

Simulation Signal Manager Task Status?

Figure C.42.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Sub Task Info Tab] C.42.) →

This background task controls and manages the operation of an Agilent 81150A Pulse 

Function / Arbitrary Waveform Generator used to simulate laser velocimetry signal bursts. 

This task is launched only when the user has selected the Enable Test Mode option on the 

System Configuration panel, Figure C.18., (Figures C.13. (C.17. (C.18.))). 

Simulation Signal Mgr Task Status? – Indicates whether the Simulation Signal 

Management task is enabled or disabled.

MC4 Scan Rig Management Task

Scan Rig Manager Task Status?

Figure C.42.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Sub Task Info Tab] C.42.) →

This background task manages a Klinger MC4 based scan rig used to position the 

measurement volume during a flow field investigation. This task is launched when the 

user selects the Initialize Scan Rig button on the Scan Rig Management Interface panel, 

Figure C.25., (Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.24. (C.25.)). →

MC4 Management Task Status? – Indicates whether the MC4 Scan Rig Management task 

is enabled or disabled.

Appendix D.32
Log File Management Task

Log File Management Task Status?

Figure C.42.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Sub Task Info Tab] C.42.) →

This background task manages a text file containing information related to the data 

acquisition process. The task is always launched at program start up.

Log File Management Task Status? – Indicates whether the Log File Management task is 

enabled or disabled.

Processed Data Management Task

Processed LV Data Manager Task Status?

Figure C.42.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Sub Task Info Tab] C.42.) →

This background task manages the data returned from the Signal/Data Processing 

program to the Data Acquisition and Control program. This task is launched when the 

user selects the Enable Online Processing and Enable Convergence Validation options 

on the System Configuration panel, Figure C.18., (Figures C.13 (C.17. (C.18.))).

Processed LV Data Manager Task Status? – Indicates whether the Processed LV Data 

Manager task is enabled or disabled.

Data Acquisition Monitoring Task

Data Acquisition Busy Line Status?

Figure C.42.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Sub Task Info Tab] C.42.) →

This indicator shows the status of the Data Acquisition Line Management signal, enabled 

or disabled. The signal is enabled (TTL High) at the start of a data acquisition cycle, and is 

disabled (TTL Low) at the completion of that data acquisition cycle.

Data Acquisition Busy Line Status? – Indicates whether the Data Acquisition Busy Line 

task is enabled or disabled.

Data Acquisition Diagnostics Information Panel

Simulation Signal Task Info Tab

(All Fields Are Display Only)

Figure C.43.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Simulation Signal Task Info Tab] 

→ C.43.)

The information on this tab presents the settings of the controls involved in the operation 

and use of an Arbitrary Waveform Generator (Agilent 81150A Pulse Function Arbitrary 

Appendix D.33
Generator) to generate electronic signal bursts driven by digital versions. The digital 

signal bursts can be generated by the Monte Carlo simulation program (Appendix A) or by 

using the laser velocimeter to digitize actual signal bursts generated in a laboratory or flow 

field environment. The function of the simulator is to verify the operation and 

measurement accuracy of the laser velocimeter data acquisition and signal/data processing 

systems. If simulated signal bursts are used, a direct comparison between simulated 

statistics and the measured statistics can be made to determine the errors induced by the 

data acquisition hardware and signal/processing software. This panel only displays the 

information, no settings can be changed.

The digitized signal bursts are retrieved from an ensemble of files, each containing a single 

burst – the format expected is the same as used by both the simulation and DA/C programs 

to store the waveforms. The simulation signal task will format a retrieved signal burst and 

load it in the arbitrary waveform generator which creates the electronic signal that is input 

to the data acquisition hardware. Since the arbitrary waveform generator has two output 

channels that can generate two signals simultaneously, testing of coincident U- and 

V-component signal bursts is the primary method of operation.

Arbitrary Waveform Generator Configuration

Figure C.43.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Simulation Signal Task Info Tab] 

→ C.43.)

This sub-panel presents the configuration of the simulation signal burst hardware when 

the LVDAS is being used in test mode, Figure C.18., (Figures C.13. (C.17. (C.18.))). The 

arbitrary waveform generator is configured by the Simulation Signal Manager sub-task, 

based on user input requested by the sub-task. The sub-task is launched when the Enable 

Test Mode button is enabled, Figure C.18. (Figures C.13. (C.17. (C.18.))).

System Configuration

81150A VISA Resource Name – Indicates the VISA name as defined in NI-MAX for 

the arbitrary waveform generator. The default value is 81150A.

81150A Channel 1 & 81150A Channel 2 – Displays the labels associated with the two 

81150A AWG channels. Channel 1 generates U-component signal bursts, and 

Channel 2 generates V-component signal bursts.

Output Signal Configuration

Amplitude (V p-p) – Reflects the voltage amplitude setting for the 81150A AWG 

channels.

Offset (0.000V) – Reflects any offset voltage imposed on the 81150A AWG channels.

Appendix D.34
Arbitrary Waveform Signal Configuration

Chan 1 ARB Wfm Name & Chan 2 ARB Wfm Name – Identifies the names 

associated with a given waveform loaded into the 81150A. As each waveform is 

identified from the list of signal burst files, retrieved from the file and loaded into 

the 81150A, it is assigned an ascending identification label. Thus the contents of 

these fields will change during the simulated data acquisition cycle. The names 

specify the measurement component (U or V) associated with it.

Chan 1 ARB Wfm Data & Chan 2 ARB Wfm Data – Presents the arrays containing 

the values of the digitized signal bursts retrieved from the disk files. These values 

will change during the simulated data acquisition cycle as each new signal burst data 

file is loaded.

Trigger Configuration

ARB Trigger Source – Identifies the trigger source for the 81150A. The External 

triggering mechanism is used during laser velocimeter applications to: a) maintain 

the simultaneity required for making valid measurements; and, b) synchronize the 

operation of the LVDAS hardware and software with the 81150A.

Trigger Mode (0: Edge) – Identifies the manner used to trigger the 81150A.

Trigger Slope (0: Positive) – Indicates the polarity of the pulse signal used to trigger 

81150A output signal generation.

Internal Trigger Frequency – Reflects the frequency of the internal 81150A 

triggering signal when ARB Trigger Source is set to Internal.

External Trigger Level – Reflects the voltage level of the external trigger that, when 

reached, enables 81150A signal output.

Input Impedance (50.0 Ohms) – Reflects the impedance setting of the 81150A 

External Trigger input.

81150A Status – Indicates if the 81150A is enabled, on-line and ready for use.

AWG Application – Identifies the operating mode of the 81150A AWG. When used with the 

LVDAS, the setting will be LDV.

Appendix D.35
Simulated LV Signal Burst

Figure C.43.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Simulation Signal Task Info Tab] 

→ C.43.)

Displays a plot of the U- and V-component signal bursts currently being output by the 

81150A. The amplitude is presented in volts, and time in nsec.

Simulation Signal Information

Figure C.43.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Simulation Signal Task Info Tab] 

→ C.43.)

Current Simulated LV Signal File – Full path and name of the file containing the digitized 

signal bursts being output.

LV Test Signal Filenames – List of file names containing the digitized signal bursts to be 

used in the test sequence.

Simulation Data Filenames – Running list of the full path and name of the signal burst 

files that have been output during the test sequence.

Triggering Simulation Files – Running list of the full path and name of the signal burst 

files that satisfied the triggering criteria of the Scope and LVTG and created a Master 

Trigger.

# Simulated LV Signal Files – Indicator showing the number of signal bursts that will be 

used in the current test sequence.

Current Simulation File No. – Indicator showing the current number of the file in the 

sequence of signal bursts being output.

Chan 1 Arbitrary Waveform Name & Chan 2 Arbitrary Waveform Name – Reflects the base 

name associated with the waveforms loaded into the 81150A. See Chan 1 ARB Wfm Name 

& Chan 2 ARB Wfm Name for more information.

U-component Burst Data (Centered) & V-Component Burst Data (Centered) – The voltage 

levels of the digitized signal bursts retrieved from the disk which have been centered in the 

AWG buffer memory. These values will change during the simulated data acquisition cycle 

as each new signal burst is loaded.

Aux Bd. (6120) Counter Used to Generate ARB Triggers – Identifies the PXI-6120 counter 

employed to generate the External triggering signal used to synchronize the outputs of the 

81150A to insure signal simultaneity in the arrival of the U- and V-component signal 

bursts at the LVDAS.

Appendix D.36
External Trigger Frequency – Indicates the default frequency setting for the PXI-6120 

counter channels listed. This value does not accurately reflect the frequency of the 

External triggers applied to the 81150A which is controlled by the rate the Master Trigger 

pulses arrive.

U-Comp Burst Min Value & V-Comp Burst Min Value – Displays the minimum U- and 

V-component signal burst voltages found in each of the digitized waveforms retrieved from 

disk. This information is maintained in a Log file.

U-Comp Burst Max Value & V-Comp Burst Max Value – Displays the maximum U- and 

V-component signal burst voltages found in each of the digitized waveforms retrieved from 

disk. This information is maintained in a Log file.

Data Acquisition Diagnostics Information Panel

Log File Info Tab

(All Fields Are Display Only)

Figure C.44.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Log File Info Tab] C.44.) →

This tab presents information related to the Log file that contains data acquisition 

information produced during the portion of a flow field investigation conducted during a 

single day. These Log files are identified by date and stored in the dated sub-directory 

containing the data ensembles acquired that day. This panel only displays the information, 

no settings can be changed.

Log File Info – This sub-panel contains information related to the management of the Log 

file.

Log File Folder – Identifies the root directory where Log files are located.

Current Log File Path – Identifies the current Log file directory path. The subdirectory containing the Log file, along with the sub-directories containing the data 

ensembles, is the coded name of the date, e.g., 101711 is October 17, 2011.

Creation Date – Identifies the date that the active Log file was created.

Creation Time – Identifies the time-of-day when the active Log file was created.

New Log File? – Indicates if the active Log file is new. The setting is used internally 

by the DA/C software to determine the actions that must be performed to properly 

record the current Log data.

Log File Label String – String containing the labels that identify the names of the 

various columns of data in the Log file.

Appendix D.37
Log File Data – This sub-panel contains the information pertaining to the current data 

acquisition cycle that will be written in the Log file.

Run Cycle # – Identifies the number of the current data acquisition cycle (point 

number)

Data Set Name – Identifies the root name of the files generated during the current 

data acquisition cycle.

LV Data Rate (Hz) – Presents the average rate signal bursts were captured during 

the current data acquisition cycle.

Acquisition Time (s) – Duration of the current data acquisition cycle in seconds.

# Records Acquired – Number of signal bursts acquired during the current data 

acquisition cycle.

# Records Processed – Indicates the number of signal bursts successfully processed 

by the Processing program. This number indicates that both the U- and 

V-component signal bursts were above the signal-to-noise threshold used in the 

Processing program. Those bursts that do not exceed the threshold represent the 

difference between Acquired and Processed numbers.

Convergence Level – Specifies the results of the convergence test in the Processing 

program (Appendix E.2.-E.3.). If the results are higher than the user selected level, 

Figure C.22., (Figures C.13. (C.17. (C.22.))), a warning would be issued to the user 

indicating that statistical stationarity had not been reached, Figure C.36, and that 

another data ensemble should be acquired at the current measurement volume 

location.

Processing Code – Code used to instruct the Processing program regarding real-time 

plotting of the mean and standard deviation results, and multiple ensemble 

processing. The code reflects the setting of the Data Ensemble Processing Options 

control shown in Figure C.34., (Figures C.13. (C.16.) [ACQUIRE DATA] C.32. →

(C.34.)).

Scan Rig Positions (W-Index, X-Index, Y-Index, Z-Index) – Identifies the index 

position of each scan rig axis at the time when the last data acquisition cycle was 

performed.

Log File Manager Command – Displays the last command issued to the Log file 

management sub-task.

Log File Manager State – Displays the status of the Log File sub-task.

Appendix D.38
New Data Series? - Indicator that defines the functionality of the Log File Manager 

sub-task as set in the Data Ensemble Processing Options control shown in 

Figure C.34., (Figures C.13. (C.16.) [ACQUIRE DATA] C.32. (C.34.)). → NEW 

indicates that a new Log file is to be created such as the case when the DA/C 

program is first used on a given day, or when a new scan grid has been loaded, thus 

requiring segregation of the data ensembles. OLD indicates that the current data 

ensemble is a continuation of the previous ensembles and that the existing Log file is 

being used.

Data Acquisition Diagnostics Information Panel

Data Management Settings/Info Tab

(All Fields Are Display Only)

Figure C.45.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Data Management Settings/Info 

Tab] C.45.) →

This panel presents information regarding data retrieval and storage operations of the 

system as well as status information related to the various hardware tasks. This panel 

only displays the information, no settings can be changed.

Data Archival Parameters/Info

Figure C.45.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Data Management Settings/Info 

Tab] C.45.) →

Primary Data Store Settings & Secondary Data Store Settings – Settings used when 

archiving the acquired data ensembles to both the primary (DA/C) and secondary 

(Processing) computers.

Root LV Path – Root directory where the data ensembles are archived.

LV Data Series Base Path – Base (root) directory where the data ensembles for the 

current data acquisition cycle are archived. In most cases this would be the Root LV

Path with a unique sub-directory name generated using the date and time, 

Figure C.21., (Figures C.13. (C.17. (C.21.))), set to the time/date when the current 

data acquisition cycle initiated.

Processed LV Data Path – Directory path indicating where the results from the 

Processing program are archived for the current data acquisition cycle. This is 

typically the LV Data Series Base Path with the added sub-directory, e.g., 

processed27-OCT-11, where the appended date (in this case October 27, 2011) is the 

date when the data ensemble was processed.

Header File String – Display of the contents of the Header (.hdr) file that contains 

the operational characteristics of the LVDAS as they were set for the current data 

Appendix D.39
acquisition cycle. The Header file is stored in the directory whose path is presented 

in the LV Data Series Base Path.

Initialization (.ini) Filename – Name of the user selected initialization file used to 

configure the LVDAS at DA/C program start-up.

Data Retrieval Parameters/Info

Figure C.45.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Data Management Settings/Info 

Tab] C.45.) →

Parameters that establish how the digitized signal bursts stored in PXI-5152 digitizer 

memory are transferred to archival disk storage on the DA/C and Processing computers 

using the LV Data Manager DLL.

Data Set Info – Listing of the components that uniquely tags a block of data (signal burst 

ensemble) retrieved from the PXI-5152 digitizer memory.

Run ID – Incrementing value that uniquely identifies the active data acquisition 

cycle.

Block Num(ber) – Incremental number value that uniquely identifies the current 

data block in a sequence of data blocks retrieved from the PXI-5152 digitizer 

memory. These values enable the data to be written to disk in proper order.

First Rec No. – Data retrieved from the PXI-5152 digitizer memory as retrieved in 

chunks (blocks). The value identifies the number of the first signal burst in the 

chunk of data being passed to the LV Data Manager.

Record Length – Length of the digitized signal burst data record.

# Recs/Block – Number of data records (signal bursts) containing the record length 

number of samples contained in the data chunk being passed to the LV Data 

Manager.

# Chans – Number of laser velocimeter data channels having data in the data 

chunk.

# Recs/Cycle – Total number of data records (signal bursts) acquired during the 

active data acquisition cycle.

Sample Rate – Rate that the digitizers sample the signal bursts during the active 

data acquisition cycle.

Appendix D.40
In addition to the data retrieval parameters described above, the following parameters are 

also used for performance monitoring and diagnostics:

Chunk Size (Blocks) – Maximum number of data records (signal bursts) that are 

contained in a single data chunk. During the data retrieval/transfer process, the 

chunk size is automatically adjusted (reduced) to accommodate the actual number of 

records contained in the chunk.

# Data Chunks To Transfer – Number of full and partial data chunks that will be 

transferred/received. This value will vary based on the number of data records 

(signal bursts) acquired.

# Data Chunks Retrieved – Number of data chunks successfully retrieved during the 

retrieval/archival process.

Data Manager Status – Status code returned by the LV Data Manager DLL 

describing the status of the last transaction. The value 0 indicates that the last 

transaction was completed without an error.

Total # Records Retrieved – Total number of data records (signal bursts) that have 

been retrieved from the PXI-5152 digitizer memory during the current 

transfer/retrieval process.

Data Retrieval/Storage Performance

Figure C.45.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Data Management Settings/Info 

Tab] C.45.) →

These indicators provide retrieval/archival process performance related feedback 

information to the operator.

Data Retrieval Start Time – Indicates the time (tick count) in milliseconds when the 

current data retrieval/archival process was started. Note that this value has no real-world 

time value. It is the value of a 32-bit counter that counts pulses occurring at a one 

millisecond interval.

Data Retrieval End Time – The time required to complete the current data 

retrieval/archival process in milliseconds.

Data Retrieval Time (Secs) – Length of time required to complete the current data 

retrieval process.

Time To Write To Disk (Secs) – Length of time required to complete archiving the just 

retrieved data sets to disk files.

Appendix D.41
Data Retrieval & Save Time (Secs) – Total time duration required to complete the current 

data retrieval/archival process.

LV Data Handler Status Information

Figure C.45.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Data Management Settings/Info 

Tab] C.45.) →

These indicators relay status information from the LV Data Manager DLL , and are 

provided for testing and verification purposes.

dmStatus – Provides a status code returned from the LV Data Manager DLL. The value 0 

indicates no errors occurred during the last transaction.

numActvDataSets – Number of data sets retrieved from the PXI-5152 digitizers currently 

being held in the queue that must be permanently archived. 

numFileNodes – Number of file info nodes in the file info queue.

numArchived – Number of data ensembles that have been archived since the start of the 

retrieval/archive process.

numLVNodes – Number of data blocks in the data queue.

numLVAuxNodes – Number of auxiliary data nodes in the auxiliary data queue.

LV Data Acquisition Results

Figure C.45.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Data Management Settings/Info 

Tab] C.45.) →

This structure contains information related to the progress of the current data acquisition 

cycle. The following parameters are included:

# Samples Requested – Number of data records (signal bursts) requested by the user at 

the start of the data acquisition cycle.

# Samples Acquired – Number of data records (signal bursts) actually acquired during the 

current data acquisition cycle.

Data Acquisition Time (secs) – The elapsed time of the current data acquisition cycle in 

seconds.

LV Data Rate (Hz) – Rate in Hertz that the current data acquisition cycle acquired the 

data record (signal burst) ensembles.

Appendix D.42
Time Out? – Indicates if the current data acquisition cycle terminated because the 

user-specified timeout limit was reached.

User Terminated? – Indicates if the current data acquisition cycle was terminated by the 

user before the requested number of records was acquired or timeout was reached.

Status/Error Information

Figure C.45.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Data Management Settings/Info 

Tab] C.45.) →

Eight unique error indicators are available to communicate status and error messages 

during the data acquisition cycle.

PXI-5152 Digitizer Errors – Displays error and status information related to activities 

performed by the PXI-5152 digitizer.

PXI-6120 Auxiliary Data Board Errors – Displays error and status information related to 

activities performed using the PXI-6120 multifunction (auxiliary data) channel.

PXI-6602 C/T Board Errors – Displays error and status information related to activities 

performed by the PXI-6602 counter/timer channel.

Scan Rig Errors – Displays error and status information related to activities performed by 

the Klinger (MC4) scan rig management sub-task.

Agilent 81150A AWG Errors – Displays error and status information related to activities 

performed by the Agilent 81150A Arbitrary Waveform Generator management sub-task.

System Errors – Displays error and status information generated while performing various 

system management activities during the data acquisition cycle.

Data Retrieval Errors – Displays error and status information generated during the data 

retrieval/archival phase of the data acquisition cycle.

Data Acquisition Diagnostics Information Panel

Processed Results Tab

(All Fields Are Display Only)

Figure C.46.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Processed Results Tab] C.46.) →

This tab contains information transmitted back to the DA/C software from the Processing 

program following the completion of signal/data processing of the current data ensemble. 

The parameters include the results of the statistical stationarity test, average minimum 

and maximum signal burst voltage levels for the U- and V-components, and average signalAppendix D.43
to-noise ratios for the two velocity components. These parameters will help guide the user 

in assessing the quality of the measurements contained in the ensemble. This panel only 

displays the information, no settings can be changed.

Data Converged? – Indicates whether or not the convergence level computed for the just 

processed ensemble of signal bursts is less than the Convergence Threshold (m/s) setting 

located on the System Configuration panel, Figure C.22., (Figures C.13. (C.17. (C.22.))). 

When the computed convergence is less than the defined acceptance threshold, this 

indicator displays YES. Conversely, if the computed convergence is greater than the 

threshold, this indicator displays NO.

Max # LV Records That Can Be Processed Together – Indicates the maximum number of 

signal bursts that can be processed together by the Signal/Data Processing program. The 

limit applies to a single or the sum of multiple ensembles acquired at the same 

measurement volume location. This value is hard coded to correspond to the internal limit 

imposed in the Signal/Data Processing program. If the Signal/Data Processing program is 

modified to allow the acquisition of a greater number of signal bursts, a Data Acquisition 

and Control program must also be modified.

Trigger Return File Path – Full path to the Trigger.Ret file generated and updated by the 

Signal/Data Processing program.

LV Data Histograms

Figure C.46.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Processed Results Tab] C.46.) →

At the completion of the signal/data processing cycle, U- and V-component, velocity 

magnitude, and vertical flow angle histograms and flow statistics developed from the 

processed data ensembles are stored in a Log file. The contents of the Log file are 

subsequently retrieved by the Data Acquisition and Control program with the update of 

the Trigger Return File at the conclusion of the processing cycle. These results and 

histograms are presented to the operator in numerical (Figure C.46.) and graphical 

(Figure C.32.) formats. It is noted that all histograms are based on coincident velocity 

measurements.

U-Component Velocity Histogram – Numeric presentation of the velocity histogram 

developed from the U-component signal burst ensemble.

V-Component Velocity Histogram – Numeric presentation of the velocity histogram 

developed from the V-component signal burst ensemble.

Velocity Magnitude Histogram – Numeric presentation of the velocity histogram developed 

from the velocity magnitude calculations from U- and V-component coincident signal 

bursts.

Appendix D.44
Flow Angle Histogram – Numeric presentation of the vertical flow angle histogram 

developed from the flow angle calculations from U- and V-component coincident signal 

bursts.

Processed LV Convergence Data

Figure C.46.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Processed Results Tab] C.46.) →

The measurement convergence data used as a test of measurement statistical stationarity 

is preserved in the Log file generated by the Signal/Data Processing program. The 

contents of the Log file are subsequently retrieved by the Data Acquisition and Control 

program with the update of the Trigger Return File at the conclusion of the processing 

cycle. The results from the convergence test are presented to the operator in numerical 

(Figure C.46.) and graphical (Figure C.32.) formats.

U-Component Velocity Convergence Data – The U-component mean velocity is computed 

for the first 100 signal bursts, first 200 signal bursts, etc., by the Signal/Data Processing 

program. The sequence of U-component mean measurements can be stepped through from 

the convergence trace.

V-Component Velocity Convergence Data – The V-component mean velocity is computed for 

the first 100 signal bursts, first 200 signal bursts, etc., by the Signal/Data Processing 

program. The sequence of V-component mean measurements can be stepped through from 

the convergence trace.

U-Component Velocity Std. Dev. Convergence Data – The U-component standard deviation 

is computed for the first 100 signal bursts, first 200 signal bursts, etc., by the Signal/Data 

Processing program. The sequence of U-component standard deviation measurements can 

be stepped through from the convergence trace.

V-Component Velocity Std. Dev. Convergence Data – The V-component standard deviation 

is computed for the first 100 signal bursts, first 200 signal bursts, etc., by the Signal/Data 

Processing program. The sequence of V-component standard deviation measurements can 

be stepped through from the convergence trace. 

U-Component Delta Velocity Convergence Data – The change in U-component mean 

velocity between each step in the convergence trace is computed by the Data Acquisition 

and Control program and the resultant trace presented in numeric format.

V-Component Delta Velocity Convergence Data – The change in V-component mean 

velocity between each step in the convergence trace is computed by the Data Acquisition 

and Control program and the resultant trace presented in numeric format.

Appendix D.45
U-Component Velocity Std. Dev. Delta Convergence Data – The change in U-component 

standard deviation between each step in the convergence trace is computed by the Data 

Acquisition and Control program and the resultant trace presented in numeric format.

V-Component Velocity Std. Dev. Delta Convergence Data – The change in V-component 

standard deviation between each step in the convergence trace is computed by the Data 

Acquisition and Control program and the resultant trace presented in numeric format.

Processed LV Data Results

Figure C.46.

(Figures C.13. (C.16.) [SYSTEM DIAGNOSTICS] C.38. [ → Processed Results Tab] C.46.) →

# LV Records Processed – Number of data records (signal bursts) within the data ensemble 

that yielded viable coincident velocity measurements.

Convergence Level (m/s) – Result from the statistical stationarity test. The standard 

deviation of each of the final five mean and standard deviation entries in the convergence 

traces (Processed LV Convergence Data) are calculated and then averaged to yield the 

measured convergence level. This level is then compared by the program with the user 

input level to determine if additional data is needed at that measurement location to reach 

statistical stationarity in the data ensemble. 

# LV Records Processed U-Component – Number of data records (signal bursts) within the 

data ensemble that yielded viable U-component velocity measurements – coincidence not 

imposed.

# LV Records Processed V-Component – Number of data records (signal bursts) within the 

data ensemble that yielded viable V-component velocity measurements – coincidence not 

imposed.

The following parameters are computed from signal bursts where at least one of the two 

simultaneously acquired signal bursts (U- and V-components) yielded a viable 

measurement. 

Avg Min Signal Burst Level U-Component (volts) (Coincident) – Minimum value for each 

signal burst is determined and the average for the ensemble calculated – U-component, 

coincident signal bursts only. 

Avg Max Signal Burst Level U-Component (volts) (Coincident) – Maximum value for each 

signal burst is determined and the average for the ensemble calculated – U-component, 

coincident signal bursts only.

Avg Min Signal Burst Level U-Component (volts) – Minimum value for each signal burst is 

determined and the average for the ensemble calculated – U-component, viable signal 

bursts occurring in either U- or V-components. 

Appendix D.46
Avg Max Signal Burst Level U-Component (volts) – Maximum value for each signal burst is 

determined and the average for the ensemble calculated – U-component, viable signal 

bursts occurring in either U- or V-components.

Avg Min Signal Burst Level V-Component (volts) (Coincident) – Minimum value for each 

signal burst is determined and the average for the ensemble calculated – V-component, 

coincident signal bursts only.

Avg Max Signal Burst Level V-Component (volts) (Coincident) – Maximum value for each 

signal burst is determined and the average for the ensemble calculated – V-component, 

coincident signal bursts only.

Avg Min Signal Burst Level V-Component (volts) – Minimum value for each signal burst is 

determined and the average for the ensemble calculated – V-component, viable signal 

bursts occurring in either U- or V-components.

Avg Max Signal Burst Level V-Component (volts) – Maximum value for each signal burst is 

determined and the average for the ensemble calculated – V-component, viable signal 

bursts occurring in either U- or V-components.

Avg SNR Values U-Component (Coincident) – Average signal-to-noise ratio of the Ucomponent signal bursts within the ensemble, coincident signal bursts only.

Avg SNR Values U-Component (Non-Coincident) – Average signal-to-noise ratio of the Ucomponent signal bursts within the ensemble, viable signal bursts occurring in either U- or 

V-components.

Avg SNR Values V-Component (Coincident) – Average signal-to-noise ratio of the Vcomponent signal bursts within the ensemble, coincident signal bursts only.

Avg SNR Values V-Component (Non-Coincident) – Average signal-to-noise ratio of the Vcomponent signal bursts within the ensemble, viable signal bursts occurring in either U- or 

V-components.

System Information

Data Acquisition and Control Program

Configuration/Management Panel

Figure C.16.

(Figures C.13. (C.16.) [SYSTEM INFORMATION])

Launches a panel containing various system information including Appendices A through 

E in pdf format. Other hardware and software related documents are also available. 

Selecting a document will launch a pdf viewer containing the document. To be 

implemented.

Appendix D.47
Quit

Data Acquisition and Control Program

Configuration/Management Panel

Figure C.16.

(Figures C.13. (C.16.) [QUIT])

Terminates the Data Acquisition and Control program, which in turn automatically 

terminates the Signal/Data Processing program. Closes all graphic windows on the 

Signal/Data Processing computer, however there will be a single command line window 

remaining that requires manual closing.

Program & System Status

Data Acquisition and Control Program

Configuration/Management Panel

Figure C.16.

(Figures C.13. (C.16.))

At the bottom of the Program Navigation panel, Figure C.16., status information is 

provided to monitor information relevant to the various system functions.

System Status – Displays the operational state of the DA/C program. Ten possible states 

are presented.

IDLE – System is in standby, but ready to perform a user selected activity.

INITAILIZING HARDWARE – Launching a data acquisition cycle activates the 

hardware initialization and configuration sequences to prepare the hardware to 

acquire data.

DATA ACQUISITION IN PROGRESS – System is actively gathering signal 

bursts.

RETRIEVING DATA – Requested data ensemble has been acquired and stored in 

the PXI system. Data ensemble currently being transferred to the DA/C computer 

memory.

STORING DATA – Data ensemble stored in the DA/C computer memory is being 

archived in the defined locations on the DA/C and Processing computer hard drives.

ACQUISITION COMPLETE – Data acquisition cycle has been completed and all 

of the acquired signal bursts and related parameters have been collected and 

archived successfully.

Appendix D.48
ACQUISITION TIMEOUT – Data acquisition cycle was terminated because the 

specified data acquisition timeout was reached prior to acquiring the user specified 

number of signal bursts.

ACQUISITION TERMINATED – Data acquisition cycle was terminated by the 

user, Terminate Data Acquisition button, Figures C.32. and C.34.

SYSTEM SHUTDOWN IN PROGRESS – System is performing various hardware 

and software cleanup activities in response to the selection of the QUIT button on 

the Program Navigation panel, Figures C.13. and C.16.

SYSTEM SHUTDOWN COMPLETED – All of the shutdown activities have been 

completed and the program can gracefully be terminated.

# Data Sets Acquired – Number of data ensembles acquired during the current data 

acquisition activity. This value is incremented at the completion of each data acquisition / 

processing cycle and preserved in the data acquisition Log file. The value is reset to zero 

each time the DA/C program is started. However, if a log file exists for a given date, the 

user is prompted with the choice of whether or not to append to that log file. If the user 

chooses to continue the existing log file by appending the new information, the program 

retrieves the last value written to that file in the # Data Sets Acquired field and initializes 

this parameter with that value.

Data Acquisition and System Control Software

Sub-Tasks

There are several small programs that are used during laser velocimetry data acquisition 

investigations to perform minor, but important functions to relieve the DA/C program from 

the overhead. Several of these tasks run in parallel with the DA/C program to provide 

flexibility and/or decrease the data acquisition cycle time. Many of the programs are 

launched when the DA/C program is started, while others execute only under user control.

LV Data File Name Generation

With thousands of digitized signal bursts needing to be archived with unique file names 

and placed in directories with names that describe something unique about the data 

ensemble it contains, this task cannot be performed manually. Thus a sub-task was 

written to automatically create the directory based on a standard selected by the user, and 

automatically use this standard to define file names with a file number suffix to store the 

digitized signal burst data. The sub-task is initiated when the DA/C program starts, and 

runs in the background executing commands generated by the DA/C program.

Appendix D.49
The inputs and methods used to develop the directory and file names are selected by the 

user in the Data Storage Management sub-panel, Figure C.21. (Figures C.13. (C.17. 

(C.21.))), shown when the Configuration button is selected in the DA/C program. The 

data storage locations must be established before the first data acquisition cycle is initiated 

by the DA/C program to insure storage of the digitized signal bursts in the desired and 

known locations. Once established and a data acquisition cycle is initiated, the sub-task 

will create the directories in the DA/C and Processing computers. As the signal bursts are 

acquired by the PXI-5152 digitizer, the sub-task is simultaneously creating a list of full 

path file names to match the number of bursts acquired. When the requested number of 

signal bursts have been digitized (or time-out or user termination occurred), the sub-task 

will pass the list of full path file names to the LV Data Management DLL which transfers 

the acquired data from the DA/C computer memory (following transfer from the PXI-5152 

memory to the DA/C computer under NI-MAX control) to the two hard drives at locations 

specified by the list.

File Path Structure

Options provided in the Data Storage Management sub-panel, Figure C.21., (Figures C.13. 

(C.17. (C.21.))), allow the user to define how the file names used to archive the acquired 

digitized signal bursts will be generated. In most cases the default Use Date/Time option 

is preferred. The sub-task will first create directories (if they do not exist) whose paths are 

entered in the Primary Base Data Storage Path (DA/C computer), and Secondary 

(Processing) Base Data Storage Path (Processing computer) [Text/Value Entry 

Fields], and if activated, create a sub-directory based on the appended date. If the Use 

Date/Time option is selected and the Append Date To Store Path is activated, the 

following file name format will be created (based on the Primary Base path):

D:\LV_Data\mmddyy\DmmddyyThhmmssFXXXX.LVB

where:

a) D: – Disk drive letter where the data records are to be stored;

b) \LV_Data\ – The directory path where the data records are to be stored;

c) mmddyy – Sub-directory based on two number codes representing month, day, and 

year when the data cycle was initiated. Acquired data records are stored in this 

subdirectory; 

d) D – A fixed letter representing date;

e) mmddyy – two number codes representing month, day, and year when the data 

acquisition cycle was initiated (leading zeros will be included);

f) T – A fixed letter representing time;

g) hhmmss – two number codes representing hour, minute, and second when the data 

acquisition cycle was initiated (leading zeros will be included, 24-hour clock used);

h) F – A fixed letter representing File number;

Appendix D.50
i) XXXX – an ascending index (0000-9999) for each unique archived data record (signal 

burst); and,

j) .LVB – Fixed file extension signifying that the file contains digitized signal bursts 

and was archived in binary format (if the ASCII option is activated during a 

recompile of the DA/C program, the extension would be LVA).

The number of file paths generated is defined by the number of records requested by the 

user. This includes file paths to both the primary and secondary storage paths. If the data 

acquisition cycle does not obtain the requested number of signal bursts because of time-out 

or user termination, the LV Data Management DLL will only create paths based on the 

created list that match the data records. That is, no empty files are created for nonexistent data.

LV Data File Structure

Given the fact that hundreds of thousands of signal burst captures can be performed 

during the course of a flow-field investigation, it is necessary to define and adhere to a 

standard method for recording the information to permanent storage. In this way the 

retrieval, manipulation and processing of the data can be standardized and automated. To 

facilitate the proper processing of the captured data and the accurate presentation of the 

resultant flow characteristics, a complete description of the manner and conditions in 

which the data records were acquired is necessary. In addition, each individual data record 

should possess sufficient information to fully describe the conditions of its origin along 

with its data content in a single self-contained file.

Although the most user friendly data file format is tab-delimited ASCII, the time required 

to transmit these large files would be prohibitive in the environment of production wind 

tunnel testing. Thus the I.E.E.E. Standard binary format was selected to minimize data 

transmission time for these large data ensembles, along with reducing the number of bytes 

needed to contain the ensemble information. Since binary files cannot be read / 

manipulated using standard office or plotting programs, it is necessary to define the 

structure of these files so that their contents can be properly read by the Signal/Data 

Processing program and other support programs written to that standard. The structural 

standard used to construct these binary files is described in Table D.1. As can be seen, the 

first nine data words describe the acquisition conditions along with the time since the 

previous signal burst was acquired followed by the conditionally sampled readings of the 

shaft encoder and auxiliary data channels. This is followed by the captured voltage trace of 

the U-component signal burst of a length given as the third of nine values in the header, 

then the captured voltage trace of the V-component. Programs designed to read these files 

should first read nine 32-bit floating point numbers followed by performing two 

consecutive 32-bit floating point array reads to retrieve the U- and V-component signal 

bursts. 

Appendix D.51
Synthetic LV Signal Generation

During the design, development and testing of the LVDAS, synthetic signal bursts were 

generated by the Monte Carlo Laser Velocimeter Simulation program (Appendix A). The 

resulting waveforms were stored to disk files so that they could be recalled and used to 

drive an Arbitrary Waveform Generator which then produced electronic signal bursts that 

were input to the LVDAS. The process was used for debugging purposes, dynamic range 

and resolution characterizations, and measurement accuracy investigations. Subsequent 

to the completion of the LVDAS, the Arbitrary Waveform Generation control program and 

associated connections were merged into the DA/C program as a sub-task. 

The primary component of the synthetic LV signal generation system is an Agilent 81150A 

arbitrary waveform generator (AWG). The AWG is a two-channel system that can be 

programmed to generate standard as well as user defined signals as required. The system 

also provides several triggering modes making it ideal for signal burst generation. The 

sub-task loads a single pair (U- and V-component) of signal bursts into the AWG memory. 

The AWG reads the loaded digital signal bursts and outputs them as analog signal bursts 

when triggered. Upon release of the analog signals, the sub-task loads the next pair of 

signal bursts based on a file listing the full path/name of the source signal burst files. Thus 

signals produced by the Simulation program can be the source, or actual signal bursts 

obtained with the laser velocimeter and captured by the LVDAS can be used as the source 

by using the auxiliary program ConvertBinary2ASCII, Appendix E, page E.10. 

The sequence of operations used to verify system functionality using the synthetic signal 

bursts follows:

1) Initialize the AWG output signal levels and the trigger source to be external;

2) Retrieve the simulated (or captured) signal bursts for the U- and V-components 

from the desired file, sequentially selected from the contents of the listing file;

3) Upload the signal bursts (in digital format) to Channels 1 and 2 of the AWG via 

USB transmission to the AWG from the DA/C computer;

4) Enable the two AWG output channels. (The signal bursts are not generated until a 

triggering pulse arrives);

5) Initialize, then arm the LVDAS;

6) Generate the external trigger pulse for the AWG using one of the digital output 

channels available on the PXI-6120 multifunction data acquisition module;

7) Perform a standard data acquisition with the LVDAS; then

8) Repeat steps 1 to 7 until all of the required sample bursts are acquired by the 

LVDAS.

LV Simulation Signal Management

Since the use of simulated signal bursts by the LVDAS is intended for system verification 

purposes only, this diagnostic capability must be manually activated and managed by the 

user. Control and management of the simulated signals is performed by a sub-task 

Appendix D.52
launched via the DA/C program after the user selects the Enable Test Mode button on 

the Configuration/Management panel, Figure D.3. (Figures C.13. (C.17. (C.18. (D.3.)))). 

Once activated, the sub-task remains activated until the DA/C program is terminated.

Actual selection and management of the synthetic signal bursts is initiated only after the 

user starts the data acquisition cycle. After the user enters the data acquisition state 

(Figures C.13. (C.16.) [ACQUIRE DATA] C.32. (C.34.)), the user is presented with the →

panel shown in Figure D.4. The 81150A AWG can be configured for synthetic signal burst 

generation and interaction with the LVDAS from this panel. The settings shown in Figure 

D.4. are the default configuration which should function correctly for most applications 

and thus should not require modification. The panel is made available to provide flexibility 

if needed for future applications.

The parameters shown in Figure D.4. are defined below:

System Configuration

81150A VISA Resource Name – [Drop Down Menu]: Specifies the VISA name as 

defined in NI-MAX for the arbitrary waveform generator. The default is 81150A.

81150A Channel 1 & 81150A Channel 2 – [Display]: Displays the labels associated 

with the two 81150A AWG channels. Channel 1 is used to generate the Ucomponent signal bursts, while Channel 2 is used to generate the V-component 

signal bursts.

Output Signal Configuration

Amplitude (V p-p) – [Value Entry Field]: Voltage amplitude range setting for both of 

the 81150A AWG channels.

Offset (0.000 V) – [Value Entry Field]: Offset voltage associated with both of the 

81150A AWG channels.

Arbitrary Waveform Signal Configuration

Chan 1 ARB Wfm Name & Chan 2 ARB Wfm Name – [Text/Value Entry Field]: 

Names associated with a given waveform loaded into the 81150A. As each simulated 

waveform is retrieved from the list of synthetic signal bursts selected by the user 

and loaded into the 81150A, it is assigned an ascending identification label. Thus 

the contents of these fields will change during the simulated data acquisition cycle. 

These names should reflect the measurement component (U or V) associated with 

that channel.

Appendix D.53
Trigger Configuration – These settings correspond to the trigger signal generated by the 

PXI-6120 multifunction data acquisition module installed in the PXI chassis.

ARB Trigger Source – [Drop Down Menu]: Identifies the trigger source for the 

81150A. Signal burst generation requires the External triggering mechanism to: a) 

maintain the simultaneity to simulate a single particle passing through the laser 

velocimeter measurement volume; and, b) synchronize the operation of the LVDAS 

with the 81150A.

Trigger Mode (0: Edge) – [Drop Down Menu]: Manner that the 81150A will be 

triggered.

Trigger Slope (0: Positive) – [Drop Down Menu]: Polarity of the pulse signal that 

will be used to trigger 81150A output signal burst generation.

Internal Trigger Frequency – [Value Entry Field]: Frequency of the internal 

triggering signal when used.

External Trigger Level – [Value Entry Field]: Level of the external trigger signal at 

which the outputs of the 81150A will be enabled.

Input Impedance (50.0 Ohms) – [Drop Down Menu]: Impedance setting of the 

81150A External Trigger input.

AWG Application – [Drop Down Menu]: Identifies the operating mode of the 

81150A AWG. For use as a signal burst generator, the application would be LDV.

Simulation Signal Selection 

Figure D.5.

(Figures D.4. [Done] D.5.) →

Once the user exits the Agilent 81150A AWG Configuration panel, the user is prompted to 

select a directory that contains the signal burst files they wish to use from the file manager 

that is launched, Figure D.5. Once the desired directory is found, the user should select 

Current Folder. 

Having selected the location containing the desired signal bursts, the DA/C program begins 

loading the AWG and acquiring the resultant electronic signal bursts in the manner of a 

normal data acquisition cycle. The simulation file manager will retrieve and load the 

contents of each simulation signal burst file in sequence into the 81150A in succession. 

There are no differences in the operation of the LVDAS, except for the source of the signal 

bursts and the control of the AWG by the DA/C program. As with a normal data 

acquisition cycle, the sequence continues until: a) the requested number of signal bursts is 

acquired; b) a timeout condition occurs; or c) the user terminates the data acquisition 

cycle.

Appendix D.54
Synthetic LV Signal File Format

The simulated signal bursts developed by the Monte Carlo Laser Velocimeter Simulation 

program are written to disk in tab-delimited ASCII format. The top portion of these files 

provides the settings used by the simulation program to generate the resulting signal burst 

file. This is followed by the U- and V-component signal bursts, where time is in 

microseconds, and the amplitude is in volts. A portion of a typical file is shown in 

Figure D.6. If captured signal bursts acquired during a laboratory or flow field 

investigation using the laser velocimeter are to be used, the binary signal burst records 

must be converted to ASCII data using the auxiliary program ConvertBinary2ASCII, 

Appendix E, page E.10. The resulting file matches the format shown in Figure D.6.

Advanced Hardware Settings

The PXI hardware platform forms the basis of the data acquisition system. The PXI 

hardware provides a great deal of flexibility enabling it to be configured to accommodate 

the needs of the user. Access to the most common settings for the LVDAS application is 

provided to the user via the user interface in the DA/C program. Access to additional 

settings of system hardware is available by selecting the Advanced HW Settings button, 

Figure D.1., on the Configuration/Management panel, Figure C.18. (Figures C.13. (C.17. 

(C.18.))). When the user selects this sub-task, the panel shown in Figure D.2. is presented. 

The parameters shown in Figure D.2. are defined below:

Laser Velocimeter PXI-Based Data Acquisition Hardware Configuration Dialog

LV Channel (PXI-5152) Settings In Tab

Figure D.2.

(Figures C.13. (C.17. (C.18. (D.1.))) [Advanced HW Settings] D.2. [ → LV Channel (PXI-5152) 

Settings In Tab])

This tab, Figure D.2., provides controls used to configure the PXI-5152 digitizer which is 

the primary device used to sample and preserve the signal bursts. The controls are very 

similar to those available in a modern digital storage oscilloscope.

General Section

Resources - [Drop Down Menu]: Links the LabVIEW software to the device name 

for the PXI-5152 channel specified in NI-MAX which provides the driver interface 

between the control software and the data acquisition hardware. All of the PXI 

hardware elements must be configured through NI-MAX before they can be accessed 

via the system software.

Channel Names(s) - [Text/Value Entry Field]: Name(s) of the digitizer channels 

available on the PXI-5152 digitizer.

Appendix D.55
Channel Section

Bandwidth - [Value Entry Field]: Defines the bandwidth of the digitizer input 

channels expressed as the frequency where the circuitry attenuates the input signal 

by 3 dB. The value 0 is the default for the PXI-5152 which sets the 3 dB point at 

340 MHz for an input impedance of 50 ohms, and 300 MHz for an input impedance 

of 1 mega ohms. 

Input Impedance - [Drop Down Menu]: Sets the PXI-5152 input impedance. The 

impedance is defaulted to 1 mega ohms since the PXI-5152 is electronically 

paralleled with the Scope which has a 50 ohm impedance to match the impedance of 

the coaxial cable connecting it to the current driving photomultipliers.

Horizontal Section

Record Length - [Value Entry Field]: Number of samples that will be digitized each 

time a signal burst generates a Master Trigger, Figure C.9., that triggers the 

digitizer. The default value is 10240.

Sample Rate - [Value Entry Field]: Rate in Hertz that the input signal burst is 

digitized. The default value is 1.0 GHz.

Vertical Section

Input Voltage Range (V p-p) - [Drop Down Menu]: Input signal voltage range in 

volts. The available options are 0.1 to 10.0 volts p-p in a 1, 2, 4, 10 sequence. The 

default setting is 4.0 volts p-p, but the signal levels should be checked routinely 

since the signal burst amplitudes can and do change during the course of the day 

because of optical alignment drift caused by tunnel vibration, flow buffeting, etc.

Vertical Offset - [Value Entry Field]: Voltage offset applied to the input signal 

bursts. Since the signal bursts are symmetric about zero volts in the LVDAS 

configuration, the default of 0 volts should be maintained.

Probe Atten. - [Value Entry Field]: Attenuation (scaling) factor applied to the input 

signal burst. This setting should match the attenuation of the input cable or probe. 

For example, a 10X or 10:1 probe would require the setting to be 10.0. In the 

LVDAS configuration, the input signal is transmitted through a 50-ohm coaxial 

cable from the photomultiplier. Thus the default value of 1.0 should be used.

Vertical Coupling - [Drop Down Menu]: Coupling setting for the input signal bursts. 

The available options are DC, AC, and GND. The DC setting passes both AC and DC 

signals, while the AC setting blocks any DC offset passing only the AC signals. GND 

grounds the digitizer inputs. The default setting of DC should be used.

Appendix D.56
Trigger Settings Section

Trigger Mode - [Drop Down Menu]: Selects the manner that a trigger signal will 

initiate the digitization of the input to the PXI-5152. The available options are 

Immediate, Software, Digital, Analog Signal or Ext. Trigger Edge and Window. 

The default setting of Analog Signal or Ext. Trigger Edge should be used since the 

LVDAS controls the hardware with the Master Trigger.

Trigger Source – [Drop Down Menu]: Source of the Trigger signal that will initiate 

the data sampling process. The available options are Channel 0, Chanel 1, or Ext. 

Trigger. Since the LVDAS uses the Master Trigger to control the hardware, the Ext. 

Trigger setting is the default and should be used.

Trigger Slope - [Drop Down Menu]: Slope of the trigger signal used to initiate the 

digitization process. The available options are Positive and Negative. The Master 

Trigger is configured to require a Negative slope setting to obtain proper timing.

Trigger Coupling - [Drop Down Menu]: Coupling setting applied to the trigger 

signal. The possible options are AC, DC, HF Reject, LF Reject, and AC Plus HF 

Reject. The AC and DC coupling options are identical to those described in the 

Vertical Coupling setting. The HF Reject setting is similar to DC coupling except 

that higher frequencies (typically >20 kHz) are rejected. The LF Reject setting is 

similar to AC coupling except the low frequency cutoff is higher (~200 kHz). The 

AC Plus HF Reject setting combines the AC and HF Reject capabilities. DC 

coupling should be used with the Master Trigger.

Trigger Level - [Value Entry Field]: Level in volts that initiates digitizing of the 

input signal. The level should be set to 1.0 volts for the Master Trigger.

Trigger Delay - [Value Entry Field]: Delay in seconds (0.0 to 10.0) that digitization 

initiates following the receipt of the Master Trigger. The delay should be set to 

0.0 seconds for LVDAS operation.

Trigger Timeout(s) - [Value Entry Field]: Amount of time to wait following receipt 

of the Master Trigger pulse before generating an error. This time is set to 0.00 for 

immediate return to the DA/C program. This transfers the verification 

responsibility that the signal burst was acquired normally to the DA/C program. 

This approach also allows the DA/C program to monitor the number of and rate that 

signal bursts were acquired.

Trigger Hold off - [Value Entry Field]: Amount of time in seconds after the arrival 

of the Master Trigger before the digitizers can be rearmed to accept the next trigger 

pulse. This is often referred to as digitizer “dead time” in laser velocimetry signal 

processing. The hold off time is set to 0.0 seconds.

Appendix D.57
Trigger Delay - [Value Entry Field]: Delay in seconds after the arrival of the Master 

Trigger when signal digitization commences. The delay time is set to 0.0 seconds.

Hysteresis - [Value Entry Field]: Specifies the size of the hysteresis window on 

either side of the trigger level in volts when the Analog Hysteresis Ref Trigger mode 

is selected. The digitizer triggers when the trigger pulse passes through the 

hysteresis value specified, has the slope specified in the trigger slope, and passes 

through the trigger level. This parameter is not used. The default setting is 

0.05 volts.

High Level - [Value Entry Field]: Upper level voltage threshold when the Window 

Trigger mode is selected. This parameter is not used. The default setting is 

0.10 volts.

Low Level - [Value Entry Field]: Lower level voltage threshold when the Window 

Trigger mode is selected. This parameter is not used. The default setting is 

0.0 volts.

Reference Pos. (%) - [Value Entry Field]: Number of pre-trigger versus post-trigger 

points that are stored. The reference position is expressed as a percent of the 

record, from 0 to 100. Since it is desired to trigger only on signal bursts generated 

by particles passing through the measurement volume near the center, the trigger 

level is set to approximately 80-percent of the peak signal levels. This results in 

obtaining signal bursts with high signal-to-noise ratios and effectively shrinking the 

size of the measurement volume. However, this would also result in a nonsymmetric signal burst in time if pre-triggering was not used. By setting this 

parameter to 40, the entire signal burst would be captured at the 80-percent trigger 

level.

Window Mode - [Drop Down Menu]: Defines whether the trigger is generated when 

the incoming signal satisfies the triggering criteria entering or leaving the window 

when the Window triggering mode has been selected. This parameter is not used.

Appendix D.58
Laser Velocimeter PXI-Based Data Acquisition Hardware Configuration Dialog

Auxiliary Channel (PXI-6120) Settings In Tab

Figure D.7.

(Figures C.13. (C.17. (C.18. (D.1.))) [Advanced HW Settings] D.2. [ → Auxiliary Channel 

(PXI-6120) Settings In Tab] D.7.) →

This panel, shown in Figure D.7., provides controls required to configure the PXI-6120 

analog input channels. The PXI-6120 facilitates the capture of analog signals from 

external sensors (pitot probes, kulites, thermocouples, etc.) that are to be conditionally 

sampled. The signals input to the analog channels are sampled once every time a signal 

burst is captured by the PXI-5152 digitizer as controlled by the Master Trigger.

6120 Analog Input Channels – [Drop Down Menu]: Identifies the device names of the 

input channels as specified in NI-MAX (LVMultiFunc).

Channel Labels – [Drop Down Menu]: Controls the unique names of the analog input 

channels of the PXI-6120. They are consecutive labels ai0-ai3 (default) and are normally 

not changed for LVDAS applications.

Input Voltage Range (V) – [Drop Down Menu]: Controls the input voltage range settings of 

the analog input channels. The available ranges are ±0.2-, ±0.5-, ±1.0-, ±2.0-, ±5.0-, 

±10.0-, ±20.0-, and ±42.0-volts. The default setting is ±2.0 volts.

Record Length – [Value Entry Field]: Length of the digitized record of the analog 

channels. Only a single measurement is obtained during LVDAS conditional sampling 

applications, thus the default setting is 0.

Sample Rate – [Value Entry Field]: Specifies the rate that the analog channels are 

digitized. Since the PXI-6120 is externally triggered by the Master Trigger in LVDAS 

applications, sample rate is not applicable.

Input Coupling – [Text/Value Entry Field]: Coupling setting for the input analog signals. 

The available options are DC, AC and GND. DC coupling passes both AC and DC signals 

into the system while AC coupling only passes AC signals. GND grounds the digitizer 

inputs. The default setting of DC should be used for LVDAS applications.

Input Terminal Configuration – [Text/Value Entry Field]: Input signal termination setting 

for the PXI-6120 analog channels. The available settings are default (RSE (Reference 

Single Ended) for the PXI-6120), Differential, NSRE (Non-Referenced Single Ended) and 

RSE (Reference Single Ended). For LVDAS applications, the default (or RSE) setting 

should be used.

Trigger Source – [Drop Down Menu]: Source of the signal used to trigger sampling of the 

signals applied to the four available analog input channels. This signal is derived from the 

Master Trigger and routed to the PXI-6120 via the PXI backplane signal PF17.

Appendix D.59
Analog Sample Clock Source – [Drop Down Menu]: Source of the clock signal used to 

initiate the digitization of signals present at the inputs of the analog channels. Since the 

analog channels are conditionally sampled in the LVDAS application, the clock source is 

the Master Trigger which produces Poisson random pulses based on the occurrence of 

seeding particles passing through the measurement volume.

Laser Velocimeter PXI-Based Data Acquisition Hardware Configuration Dialog

LV System Trigger Settings In Tab

Figure D.8.

(Figures C.13. (C.17. (C.18. (D.1.))) [Advanced HW Settings] D.2. [ → LV System Trigger 

Settings In Tab] D.8.) →

Trigger Definition Section

Trigger Source Terminal – [Drop Down Menu]: Sets the source (hardware terminal) 

of the start acquisition trigger. The source should be set to the default Reference 

Trigger which is derived from the Master Trigger in LVDAS applications.

System Trigger Terminal – [Drop Down Menu]: Establishes the terminal where the 

start acquisition trigger required by other devices in the PXI chassis can be 

obtained. The default setting of PXI_Trig0 should be used for LVDAS applications. 

Trigger Name – [Text/Value Entry Field]: Defines the label associated with the 

System Trigger signal.

Trigger Polarity – [Drop Down Menu]: Sets the polarity of the System Trigger 

Signal. The default setting of non-inverted should be used for LVDAS applications.

Counter Generated Trigger Definition Section

This group of controls enables one of the counters available on the PXI-6120 Multifunction 

module to generate trigger signals. The counter system was used during system 

development to verify system operation when signal bursts were neither available from the 

laser velocimeter or synthetic signals produced by an Arbitrary Waveform Generator. This 

capability is not required for LVDAS applications.

Trigger Pulse Frequency (Hz) – [Value Entry Field]: Rate in Hertz that trigger 

pulses are generated by the counter. The default setting is 1 Hz.

Initial Delay – [Value Entry Field]: Delay time in seconds after the counter has been 

armed before the first trigger signal is generated.

Trigger Pulse Duty Cycle – [Value Entry Field]: Sets the duty cycle of the trigger 

pulse train.

Appendix D.60
Trigger Idle State – [Drop Down Menu]: Sets the quiescent state of the trigger 

signal. The default setting is TTL Low, which should be used in most applications.

Counter Enable – [Button]: Sets the counter circuitry of the PXI-6120 to be used for 

generating the trigger signals.

Trigger Signal Routing Section

Trigger Destination #1 & Trigger Destination #2 – [Drop Down Menu]: The 

flexibility inherent to the PXI system provides the ability to route system signals 

using software commands to different hardware connectors on the various system 

devices. These controls define the destinations of the Reference trigger (derived 

from the Master trigger) generated by the PXI-5152 digitizer. PXI Trigger Line 

0/RTSI 0 reflects the routing of the Reference trigger signal to the PXI back plane 

making it available to other devices residing in the PXI chassis. PFI 1 reflects the 

routing of the Reference trigger to the PFI 1 connector on the PXI-5152 front panel.

Scan Rig – Grid Generation

During a typical flow field investigation, the user will normally acquire data ensembles 

throughout a grid of locations in order to develop a better understanding of the flow field. 

In order to minimize data collection and facility run times, it is often desirable to define 

the grid of interest prior to initiating data collection so that the laser velocimeter 

measurement volume can be quickly relocated using a scanning system. To facilitate this 

capability, mechanisms are included in the DA/C program so that the user can generate, 

then utilize a data collection grid. Generated grid locations can be preserved in a userdefined disk file so that the grid can be recalled at a later time. The format of this file is 

detailed in a later section.

Grid generation of the measurement volume spatial locations for the Klinger MC4 based 

scan rig is initiated by selecting the Create Scan Grid File button on the Controls tab 

of the Scan Rig Management Interface Panel (Figure C.24.), Figure D.9. (Figures C.13. 

(C.16.) [CONTROL SCAN RIG] C.24. (D.9.)). When this button is selected, the Scanner →

Position Generator panel, Figure D.10. (Figure C.26.), will be displayed. This panel 

presents the controls and settings to generate the scan position grid. These controls are 

divided between a tab control and a group of controls that operate independently from the 

controls on the tab.

Controls provided on the Settings tab allow the user to generate a range of scan grid 

locations for the four axes supported by the MC4 system. 

Appendix D.61
Scanner Position Generator Panel

Settings Tab

W-Axis, X-Axis, Y-Axis, & Z-Axis Settings 

Figure D.10. (C.26.)

(Figures C.13. (C.16.) [Control Scan Rig] C.24. (D.9.) [ → Create Scan Grid File] D.10. →

[Settings Tab])

Since the positioning of the measurement volume requires independent movements of one 

or more axes, it is essential that these locations be defined independently. Thus the Axis 

specific location generation controls are broken out into individual sub-panels. Each of 

these sub-panels have controls that provide the user with the tools needed to define the 

movements on a given axis:

Units – [Button]: Defines the units that will be used when converting the step size and 

scan start position data into scan rig counts. The available options are Inches and Counts. 

If Inches is selected, the application will convert the position data to inches. When Counts 

is specified, no conversion is performed and the positions are handled directly.

Step Size – [Value Entry Field]: Size of each successive step (distance between desired 

measurement volume locations) to be generated in Counts or Inches.

Scan Start Position – [Value Entry Field]: Position of the first measurement volume 

location in Counts or Inches.

# Scan Indices – [Value Entry Field]: Defines the number of scan indices that will be 

generated automatically when the operator selects the Generate Scan Data button at 

the bottom of the panel.

Travel Per Step – [Value Entry Field]: Travel distance in inches of a single count (1 step of 

the stepping motor driving the axis). The MC4 scan rig moves 39.37 micro-inches 

(3.93700E-5 inches) per count (step). This default value should remain unless a different 

scan rig is used.

Scan File Title – [Text/Value Entry Field]: Title of the measurement volume location grid.

Scan File Comment – [Text/Value Entry Field]: Description of the generated measurement 

volume location grid.

Scan Rig ID – [Text/Value Entry Field]: Name of the scan rig for which the generated 

measurement volume location grid was created.

Appendix D.62
Scanner Position Generator Panel

Active Grid Tab

W-Axis, X-Axis, Y-Axis, & Z-Axis Settings 

Figure D.11.

(Figures C.13. (C.16.) C.24. (D.9.) D.10. D.11.) → → →

This tab displays the measurement volume location grid, Figure D.11., generated using the 

parameter settings contained on the Settings tab (Figure D.10.) the last time the 

Generate Scan Data button was selected. The display provides the user with the 

opportunity to verify the grid locations before committing them to the Final Grid.

Clear Data – [Button]: Removes all entries from the measurement volume location grid.

# Indices – [Indicator]: Number of grid positions in the active grid.

Scanner Position Generator Panel

Complete Grid Tab

W-Axis, X-Axis, Y-Axis, & Z-Axis Settings 

Figure D.12.

(Figures C.13. (C.16.) [Control Scan Rig] C.24. (D.9.) [ → Create Scan Grid File] D.10. →

[Complete Grid Tab] D.12.) →

This tab displays the entire grid of measurement volume locations, Figure D.12., including 

those added when the Append To Final Grid button has been selected. The presented 

measurement volume location grid is the data that will be committed to disk file after the 

user selects the Save Scan Data To File button.

Clear Data – [Button]: Removes all entries from the measurement volume location grid.

# Indices – [Indicator]: Number of grid positions in the complete grid.

Scanner Position Generator Panel

Information Tab

W-Axis, X-Axis, Y-Axis, & Z-Axis Settings 

Figure D.13.

(Figures C.13. (C.16.) [Control Scan Rig] C.24. (D.9.) [ → Create Scan Grid File] D.10. →

[Information Tab] D.13.) →

This tab displays detailed information about the generated measurement volume location 

grid, Figure D.13.

W-Axis, X-Axis, Y-Axis, & Z-Axis Indices – [Indicator]: Indicators presenting the most 

recently generated position indices for each of the W, X, Y, and Z axes after the last 

selection of the Generate Scan Data button.

Appendix D.63
# Counts Per Inch – [Indicator]: Number of scan rig counts per inch of travel (inverse of 

the Travel per Step entry in the Settings tab).

Import Date – [Indicator]: Date when an imported measurement volume location grid file 

was created.

Import Time – [Indicator]: Time of day when an imported measurement volume location 

grid file was created.

New Scan Position File Path – [Indicator]: Displays the path to the measurement volume 

location grid file that was saved after the Save Scan Data To Disk button was selected.

Imported Scan File Path – [Indicator]: Displays the path to the measurement volume 

location grid file that was last imported into the Scan Position Generator.

Date – [Indicator]: Date when the generated measurement volume location grid was saved 

to disk.

Time – [Indicator]: Time-of-day when the generated measurement volume location grid 

was saved to disk.

Error In & Error Out – [Indicator]: Indicators will display information regarding errors 

that occur while using the Scanner Position Generator.

Scanner Position Generator Panel

Primary Controls

Figure D.14.

(Figures C.13. (C.16.) [Control Scan Rig] C.24. (D.9.) [ → Create Scan Grid File] D.10. →

(D.14.))

The controls that execute sub-tasks needed to create, edit, and store the measurement 

volume location grid are presented in a row of buttons at the bottom of the panel, 

Figure D.14., which apply the settings and selections made within the tabbed sub-panels.

Generate Scan Data – [Button]: Generates the measurement volume location grid based 

on the values entered in the Settings tab. Once this button has been selected, the 

Append To Final Grid button changes color to yellow and begins to blink a a reminder 

that new position data is available and ready to be transferred/appended to the complete 

grid.

Import Existing Scan Data – [Button]: Presents a file manager panel that allows the user 

to select a file containing a measurement volume location grid generated previously using 

the Scan Position Generator. The contents of the file are imported to the Active Grid table 

so that they may be appended to the Complete Scan Grid (Counts) table. Refer to the Scan 

Appendix D.64
Grid Position File Information tab for details regarding the contents and format of this 

custom file.

Import Scan Data From File – [Button]: Presents a file manager panel that allows the user 

to select a file containing measurement volume locations generated by an external 

program. The file should be in tab-delimited ASCII format of four columns, one for each of 

the four supported scan axes. No labels should appear at the top of each column. The 

contents of the file are imported to the Active Grid table so that they may be appended to 

the Complete Scan Grid (Counts) table.

Append To Final Grid – [Indicator Button]: Once the Generate Scan Data button has 

been selected, the Append To Final Grid button will begin blinking and change color to 

yellow. When selected the contents of the Active Grid table will be copied to the Complete 

Scan Grid (Counts) table.

Save Scan Data To File – [Indicator Button]: Stores the contents of the Complete Scan 

Grid (Counts) table to a custom disk file. The button will present a file manager panel to 

allow the user to select the directory where the file is to be archived. Refer to the Scan 

Grid Position File Information tab for details regarding the contents and format of this 

custom file.

Quit – [Button]: Terminates the Scanner Position Generation panel and returns control to 

the DA/C program where the user is prompted by the panel shown in Figure D.15. If the 

last measurement volume location grid created prior to executing this Button is desired to 

be used by the DA/C program, the user should select Yes in the panel.

Once the user has selected a measurement volume location grid, either when exiting the 

Scanner Position Generation panel or by selection using the Load Scan Position File 

button, Figure D.9. (Figures C.13. (C.16.) [CONTROL SCAN RIG] C.24. (D.9.)), the user →

will be prompted via a panel, Figure D.16., to select the axis that, when scanned will cause 

the running data plot on the Processing computer to be reset, Appendix E.8.

Scan Grid Position File Information

Measurement volume location information resulting from the operations performed within 

the Scanner Position Generation panel can be preserved to disk file when the user selects 

the Save Scan Data To File button (Figures D.10. (D.14.)). The file created is a tabdelimited file containing descriptive information at the top followed by scan rig location 

data in counts for each of the four axes supported by the MC4 scan rig controller. A 

portion of an example file is shown in Figure D.17. The contents of the file may be 

manually edited using a text editor or preferably a spreadsheet application such as 

Microsoft Excel or Libre Office Scalc. Make sure that the resultant file is saved as tabdelimited text and not in Excel or Scalc format.

Appendix D.65
32-Bit Word Number(s) Data Value

0 LV Data Record Number

1 Sample Rate

2 Record Length

3 Interarrival Time

4 Rotor Azimuth Position

5 Auxiliary Channel Ain0 Value

6 Auxiliary Channel Ain1 Value

7 Auxiliary Channel Ain2 Value

8 Auxiliary Channel Ain3 Value

9 to (9+RL) U-Component Digitized LV Burst Signal Data Voltage Samples

(10+RL) to (10+2RL) V-Component Digitized LV Burst Signal Data Voltage Samples

Table D.1.- Definition of the data record header (first nine 32-bit values) contained in Binary formatted LV 

data files.

Appendix D.66
Figure D.1.- Advanced HW Settings button – located on Configuration tab.

Figure D.2.- Advanced HW Settings – LV Signal Digitizer (PXI-5122) advanced options tab.

Figure D.3.- Test mode / simulation (synthetic) signal operational selection.

Appendix D.67
Figure D.4.- LV synthetic signal management – Agilent 81150A AWG Configuration Dialog.

Figure D.5.- Simulated LV signal selection dialog.

Appendix D.68
Figure D.6.- Simulated LV signal file format.

Appendix D.69
Figure D.7.- Advanced Hardware Configuration – Auxiliary Channel Settings.

Figure D.8.- Advanced hardware Configuration – LV System Trigger Settings.

Appendix D.70
Figure D.9.- Create Scan Grid File option.

Appendix D.71
Figure D.10.- Scanner Position Generator dialog.

Appendix D.72
Figure D.11.- Active Grid – Scan Rig Position data tab.

Appendix D.73
Figure D.12.- Complete Scan Rig Position data tab.

Appendix D.74
Figure D.13.- Scan Position Generator Information tab.

Appendix D.75
Figure D.14.- Primary Scan Position Generator Controls.

Figure D.15.- Scan grid file use prompt.

Figure 16.- Scan axis plot reset selection dialog.

Appendix D.76
Figure D.17.- Scan Grid Position File – generated using Scanner Position Generator.

Appendix D.77
Appendix D.78
Appendix E

Signal Processing / Data Processing Software

Contrary to conventional approaches to laser velocimetry signal processing, the 

combination of COTS (Commercial Off The Shelf) high-speed digitizers and software signal 

processing techniques operating on standard PC-type computers was selected. While the 

concept was first used back in 1975 (Griskey (1975)) it was more a laboratory curiosity 

than a realistic approach to signal processing. Although it was limited to low velocity 

liquid flows, it did show far better measurement accuracies than obtainable with the then 

state-of-the-art high-speed burst counters. The primary concern in its choice for the 

upgraded laser velocimeter was whether each signal could be processed in a timely manner 

to provide at least near real time results. However, the potential advantages of capturing 

and storing the raw signal bursts, and increased measurement accuracy were too 

intriguing to ignore the challenge.

When contemplating the design of such a system, one realizes that this is not a laboratory 

exercise but the development of a production based measurement system that will be used 

by researchers that are not experts in laser velocimetry, electronics or signal/data 

processing software. In order to reduce the risks, a Monte Carlo based laser velocimetry 

simulation program (Appendix A) was upgraded for the production of simulated LV signal 

bursts to be used in data acquisition and data processing simulations. These signal bursts 

would be used to develop and test signal processing algorithms for instrument precision 

and measurement accuracy along with processing speed. The results from these studies 

are outlined in Chapter IV. They show that the instrument precision was far better than 

specifications required while signal/data processing was conducted at speeds acceptable for 

real-time processing. The entire upgraded laser velocimeter, including the signal/data 

processing software were tested under realistic conditions in the laboratory and in the 

BART, Chapters V and VI, respectively. All expectations were met except that the data 

transfer time from the data acquisition computer memory to disk storage on the 

acquisition and processing computers was excessive, and spontaneous impulses generated 

by the photomultiplier caused false signal captures. These problems have since been 

corrected and the system is considered operational. Further laboratory and wind tunnel 

tests were conducted in the laboratory and the BART to assess its performance. The 

results of these investigations are outlined in Chapter VII.

Computed Statistics and Data Storage

The Laser Velocimeter Signal / Data Processing Program will determine the signal 

frequencies contained within each captured LV signal burst that comprise an ensemble of 

measurements obtained by the Laser Velocimeter Data Acquisition system. Each captured 

signal burst is processed with Fast Fourier Transform (FFT) technology using up to 8192 

of the 10,000 digital samples of each burst acquired by the two-channel, 1.0 GHz per 

channel digitizer. The U- and V-component signals are monitored on a high-speed, digital 

oscilloscope. One user selected channel is used to trigger both the oscilloscope and the 

Appendix E.1
high-speed digitizer. Normally the trigger level is set to approximately 80-percent of the 

peak value to limit the size of the measurement volume when using monodisperse particles 

for seeding. The signal bursts from both components are captured simultaneously in their 

entirety by utilizing the pre-trigger capabilities of the high-speed digitizer. Once the 

frequency contained in each signal burst has been determined, the program will use the 

input system characteristics to calculate the respective particle velocities. The U-and Vcomponent velocity ensembles are then processed using three methods:

1) Standard statistics;

2) Sample-and-Hold techniques in an attempt to reduce/eliminate particle sampling 

bias (Edwards (1987)); and,

3) Technique used to lessen the effect of particle sampling bias on the statistical results 

(Edwards and Meyers (1984), Meyers et al (1990), Meyers (1991)).

The following statistics are calculated for the three data processing methods:

1) Mean and its statistical uncertainty;

2) Standard deviation and its statistical uncertainty;

3) Skew; and,

4) Excess

These statistics are computed for:

1) U-component velocity;

2) V-component velocity; and since the U- and V-component measurements are 

coincident,

3) Velocity magnitude; and,

4) Flow angle.

Also the following parameters are determined:

1) Velocity:Data Rate Correlation Coefficient;

2) Average convergence standard deviation among the U- and V-component means and 

standard deviations based on the last five points of the rolling statistics calculated 

for the data ensembles as they grow by 100 signal burst increments;

3) Estimated integral time scale;

4) Number of acceptable signal bursts processed;

5) Total measurement time;

6) Estimated number of integral time scales obtained;

7) Reynolds stress;

8) Tables of:

1. Arrival times for each signal burst,

2. If a rotor encoder is used, azimuth angle,

3. U-component velocity,

4. V-component velocity,

Appendix E.2
5. Velocity magnitude,

6. Flow angle,

7. Minimum and maximum signal voltages, and,

8. Particle transit time through the measurement volume.

These statistical results and tables are stored in the LOG file accompanying the ensemble 

of digitized signal bursts in the sub-directory named by the date and time of the ensemble 

acquisition, e.g., D011911T125816 January 19, 2011 at 12:58:16 (24-hour clock). This →

file along with other output files are placed in the processed sub-directory created and 

attached to the ensemble directory by the program, e.g., processed19-JAN-11. If the 

signals are processed again at a later date, a new processed sub-directory will be created 

with the date of that processing – the original processing sub-directory is left intact. An 

example of a LOG file is shown in Table E-1. 

The program also plots the U- and V-component mean and standard deviation results as a 

function of ensemble size. These plots serve as a guide to indicate whether statistical 

stationarity has been reached by the acquired data ensemble. Along with this visual 

indicator, the standard deviation of the last five points on each plot is determined, and the 

average of the four results is returned to the Data Acquisition Program. This data will be 

compared with the user selected limit that provides the test for statistical stationarity. If 

the returned value is greater than the selected limit, the Data Acquisition Program will 

flag the user indicating that statistical stationarity has not been reached, and that another 

ensemble should be acquired at that measurement location. If a second (or third, etc) 

ensemble is acquired, the processing program will compute the results and statistics as if 

all of the ensembles acquired at that location comprised a single ensemble.

The four plots showing the convergence of the U- and V-component mean velocity and 

their standard deviations will remain displayed on the screen until the user moves the 

cursor to the upper left plot (U-component mean) and left-clicks the mouse. At this point 

the program will display the histograms of the U- and V-component velocities, velocity 

magnitude and flow angle. Again these plots will remain displayed until the user moves 

the cursor to the upper left plot (U-component) and left-clicks the mouse. The program 

will then return to the sleep mode awaiting the arrival of the next data ensemble. If the 

Auto View Timing? box was selected on the setup screen and a display time entered in the 

Display Time, sec box, user interaction is not required or accepted. The convergence plots 

will display for the selected time, the screen will clear and the histogram plots will display 

for the same amount of time, then the screen will clear and the program returns to the 

sleep mode. The user may choose to automatically save these plots in the processed subdirectory for that ensemble by activating the Save Plots? box in the setup screen. The 

eight plots are saved as Enhanced Windows Metafiles (EMF).

Finally, an overall log file (*.ALL) is saved in the processed sub-directory for the first 

ensemble processed after program start-up. The log file contains a table of all of the above 

mentioned statistical results in a tab-delimited ASCII format. This table will be added to 

for each new data ensemble processed until the program is terminated. If multiple 

Appendix E.3
ensembles are acquired to obtain statistical stationarity, the results for each stage is 

recorded, e.g., ensemble 1, ensemble 1 & 2, ensemble 1 & 2 & 3, etc. The processing 

program also automatically runs the program RUNNINGDISPLAY that presents a 

running plot of the means and standard deviations for the U- and V-component velocities, 

velocity magnitudes and flow angles throughout a scan profile. This provides real-time 

feedback to the user of the velocity profiles as the flow is being interrogated. When a new 

profile is begun, as controlled by the Data Acquisition Program, the current running plots 

are erased and plots for the new scan begun. These plots are not saved as they can be 

regenerated with user settings from the ALL log file using any X-Y plot program.

The results from all three methods are stored in the LOG file, but only the Normal 

Statistical results are plotted and stored in the cumulative ALL file. The program requires 

approximately 50 seconds to process 10,000 signal burst pairs (U- and V-components). The 

statistics calculated include the mean, statistical uncertainty in the mean, standard 

deviation, statistical uncertainty in the standard deviation, skew, and excess along with the 

number of measurements included in the calculations. These statistics are determined for 

each of the three processing methods for the U- and V-component velocities, velocity 

magnitude and flow angle.

User Input Screen

The data acquisition and signal/data processing functions are performed by two networked 

server-class PC computers. The data acquisition computer runs the LabView-based data 

acquisition and hardware control program and serves as the user interface for all functions 

including the signal/data processing program. The signal/data processing program is 

started on the second computer during the final checks of the system when the small 

particle generator is used to validate proper operation of the entire system. The program 

can be started locally on the signal/data processing computer or remotely by using the 

program TeamViewer to control the signal/data processing computer including program 

execution. The program may be started by double clicking on the FringeLVprocessing.exe 

file. A command (DOS) window will open followed by the graphical user interface shown 

in Figure E.1. (NOTE: It is recommended that the DOS box should be opened by the RUN 

command: COMMAND.COM, then navigate to the program location and run the program 

via the command string fringelvprocessing. This is recommended because if the 

program fails, error messages are presented in the command (DOS) window. 

Unfortunately a temporary DOS window obtained by double clicking the EXE file, will 

disappear if the program which opened the window crashes. Any error messages will then 

be lost. If the DOS window is opened first, it will remain open to display the error 

messages.) The user inputs to the opening screen, Figure E.1, are described below:

Laser Wavelength, microns:

Click on the desired box and a data entry window will open. Enter the appropriate 

laser wavelength in microns for that selected component. The new installation 

setting is 0.0.

Appendix E.4
Cross Beam Angle, degrees:

Click on the desired box and a data entry window will open. Enter the appropriate 

cross beam angle (full angle) in degrees for that selected component. The new 

installation setting is 0.0.

Bragg Frequency, MHz:

Click on the desired box and a data entry window will open. Enter the appropriate 

Bragg frequency in MHz for that selected component. The new installation setting 

is 0.0.

IF Frequency, MHz :

Click on the desired box and a data entry window will open. Enter the mixing 

frequency in MHz that feeds the reference side of a double-balanced mixer, e.g., 

Bragg = 40 MHz, IF = 30 MHz yields an effective 10 MHz Bragg shift. If the 

acquired signal is not downmixed, the IF frequencies should be set to 0.0. The new 

installation setting is 0.0.

Negative Doppler Shift?

Click on the desired box and if the box was blank, an X will show indicating a YES 

response. Clicking on the box with the X showing will remove the X. Since the TSI 

optical system uses a Bragg cell to both separate the colors and add the Bragg 

frequency offset, there is no option as to which of the output beams is shifted. Thus 

if a positive velocity yields a negative result, click the appropriate box to have the 

program automatically reverse the sign. The new installation setting is blank.

Delta Azimuth, deg:

Click on the box and a data entry window will open. If a shaft encoder is used, enter 

the wedge angle in degrees to be used to determine the statistical parameters. For 

example, a wedge angle (Delta Azimuth) of 3.0 degrees will determine the U- and Vcomponent velocities, velocity magnitude and flow angle statistics for only those 

measurements that occur within that wedge angle throughout the acquisition time. 

This wedge angle will yield 120 separate statistical data sets to cover the entire 

revolution of the shaft (rotor). No convergence, histogram, or real time running 

plots will be displayed. These must be determined off-line. However, the mean 

velocity and standard deviations are plotted as a function of azimuth for the U- and 

V-velocity components, velocity magnitude and flow angle. The new installation 

setting is 0.0.

Remove Outliers?

Click on the box and if the box was blank an X will show indicating a YES response. 

Clicking on the box with the X showing will remove the X. This function, if selected, 

will remove outliers from the distributions. The technique begins by determining 

the histogram for the U-component velocity with a resolution of 1.0 m/s. The peak 

of the histogram is then determined and a threshold calculated to be 5.0-percent of 

the peak value (equivalent to the amplitude at the 1/e2 width for a Gaussian 

Appendix E.5
distribution). This histogram is traced from the peak location in the positive 

velocity direction until the histogram level falls below the threshold. The velocity of 

the previous bin becomes the upper velocity limit unless the level of one of the next 

three bins is above threshold which then becomes the new upper limit. The process 

is repeated in the negative direction to determine the minimum velocity. The 

technique is then applied to the V-component velocity ensemble. When completed, 

the U- and V-component ensembles are interrogated and any outlier found removes 

not only that component measurement, but the other component entry as well as 

the corresponding velocity magnitude and flow angle entries. It is recommended 

that this option be selected (and is the new installation setting) unless it is known 

that the data will be sparse or a shaft encoder is used which could make the 

histograms sparse.

Save Plots?

Click on the box and if the box was blank, an X will show indicating a YES response. 

Clicking on the box with the X showing will remove the X. This function, if selected, 

will save the Convergence and Histogram plots (or Azimuth statistical plots if Delta 

Azimuth is greater than 0.0). The plots are stored in the processed sub-directory of 

the data ensemble directory in Enhanced Windows Metafile (EMF) format. The new 

installation setting is a blank box.

Binary Data?

Click on the box and if the box was blank, an X will show indicating a YES response. 

Clicking on the box with the X showing will remove the X. If selected, this function 

will inform the program that the data received from the Data Acquisition Program 

is in standard IEEE binary format. Otherwise the data will be expected to be in 

ASCII format. It is recommended that binary data be transferred because the much 

smaller data ensemble size will lower the acquisition turn around time. The new 

installation setting is an X showing.

Auto View Timing?

Click on the box and if the box was blank, an X will show indicating a YES response. 

Clicking on the box with the X showing will remove the X. If Selected, the Display 

Time, sec box will become active so the user can select the amount of time the plots 

will be shown. Otherwise, the plots will stay displayed until the user moves the 

cursor to the upper left plot and left clicking the mouse which then clears the plots 

and will display the next set of plots. The new installation setting is a blank box.

Display Time, sec:

Click on the box and a data entry window will open. Enter the time in seconds that 

the plots are to be displayed. If the entry is less than 3.0 seconds, the program will 

automatically set the display entry to 3.0. If the display is less than 3.0 seconds, it is 

possible that internal timing may result in a hung program especially if the 

BATCHLVPROCESSING program is controlling processing instead of the Data 

Acquisition Program. For this reason, if a time less than 3.0 seconds is input, the 

Appendix E.6
program will automatically set the time to 3.0 seconds. The new installation setting 

is a blank box.

Trigger File:

Click on the box and the internal file manager will open. Use the file manager to 

select the file that will be used to control signal / data processing. This file MUST be 

the same file selected by the Data Acquisition Program or the Batch Processing 

Program. If the file does not exist, click on the New Trigger File? box to erase any 

information in the Trigger File: box, then click on the Trigger File: box. A data 

entry screen will then open where the user can enter the full path and file name of 

the new trigger file. This will then create the last subdirectory in the path along 

with the entered file name for use as the trigger file. The new installation setting is 

the message “Select Trigger File”.

List Velocities?

Click on the box and if the box was blank, an X will show indicating a YES response. 

Clicking on the box with the X showing will remove the X. If selected, the U- and Vcomponent velocities for each particle will be displayed in the DOS box as they are 

determined. The new installation setting is a blank box.

Run

Click on the box to start the Signal / Data Processing program. The program now 

runs hands off under the total control of the Data Acquisition Program or the Batch 

Processing Program. The data entry screen can not be entered again until the 

program is terminated by the controlling program and restarted. It is noted that the 

Signal / Data Processing program must be started before the first data ensemble is 

acquired by the Data Acquisition Program or the Batch Processing Program is RUN.

Exit

Click on the box to exit the program without doing any signal / data processing.

When all the data has been entered, the Run command is selected. The program will 

overwrite the INI file with the new parameter values/settings so that they are loaded when 

the Signal / Data Processing Program is started the next time, thus eliminating the need to 

reenter the values/settings. The program will also read the time signature on the selected 

Trigger File, and start the real-time display program RunningDisplay.exe. The program will 

then go into sleep mode for 1.0 second, after which time it will wake up and interrogate the 

time signature on the Trigger File. If the time signature is the same as recorded previously, 

the program will go back to sleep for 1.0 second, then wake up and check again. This 

process continues until the time signature changes indicating that a new data ensemble 

has been stored on the signal / data processing computer hard drive by the Data 

Acquisition Program, and that the information needed to process that data ensemble has 

been stored in the Trigger File. If the program is controlled by the Batch Processing 

Program, the same sequence will determine when the Trigger File has been overwritten by 

with the next data ensemble Trigger File indicating that the next ensemble is available for 

Appendix E.7
processing. The new time signature now becomes the reference time and the Trigger File 

opened, the information read and signal processing begins.

Auxiliary Programs

The following programs provide additional capabilities to the Signal / Data Processing 

program along with programs to interrogate the original ensembles. All programs and 

their support INI, BAT, etc., files must be located in the same directory as the Signal / Data 

Processing program.

Grwnd

This program provides the graphics engine for the data entry screens and the graphics 

screens presenting the plots. The program is run and controlled from other programs and 

there is not direct user interaction with the program. The program is described and it, 

along with supporting routines, can be obtained from:

http://spdg1.sci.shizuoka.ac.jp/grwinlib/english/

It is a general purpose graphics utility library that is available for most 32- and 64-bit 

Fortran and C/C++ compilers. Along with fundamental graphics controls and commands, 

the library contains advanced plotting utilities, e.g., graphs with hidden lines and contour 

diagrams, etc.

RunningDisplay

This program provides the real-time displays of mean and standard deviation profiles with 

statistical error bars for the U- and V-component velocities, velocity magnitude and flow 

angle. The program is started, controlled and terminated by the Signal / Data Processing 

program. There is no user interaction with the program other than following commands 

generated by the Data Acquisition program:

new Begin a new velocity/flow angle profile;

run Plot the statistical results from the process ensemble (along with a re-plot of 

all the previous data in the current profile;

rep Current ensemble is a repeat acquisition at the same measurement location as 

the previous ensemble; and

exit Terminate the program.

The program automatically scales the plots since there is no a priori knowledge of the 

velocity/flow angle values or scan distances that will be plotted. If a new scan is started as 

signified by the command “new”, the data arrays would be cleared and new plots begun. 

The display program will be terminated by the Signal / Data Processing program as part of 

its termination procedure that was initiated by the command “exit”. It is noted that this 

program will not be started if the Delta Azimuth setting is not 0.0.

Appendix E.8
BatchLVprocessing

This program acts as a surrogate for the Data Acquisition and Control program when a 

series of data ensembles is desired to be processed off-line. It provides a batch processing 

capability where data from an entire day's run can be automatically processed without user 

intervention. This program will communicate and control the Signal/Data Processing 

program in the same manner as the LabVIEW program. It is strongly recommended that 

this program and the Signal/Data Processing program be run and operated in the following 

sequence to avoid potential conflicts with the graphics windows:

1) Run the Signal/Data Processing program (preferably in a Command.com window) 

– Do not go further with this program.

2) Run the BatchLVprocessing program (preferably in a Command.com window)

– Do not go further with this program.

3) Adjust the commands/settings/selected files in the data entry screen for the 

Signal/Data Processing program to match the data ensembles to be processed.

4) In the data entry screen for the BatchLVprocessing program, select the EXACT 

same Trigger File chosen for the Signal/Data Processing program.

5) Click the RUN command button in the Signal/Data Processing program.

6) Click the RUN command button in the BatchLVprocessing program.

7) When the entire set of data ensembles have been processed, both programs will 

automatically terminate with messages to close the graphics windows.

Once the RUN command button is selected in the BatchLVprocessing program, the full 

path to the Trigger File is interrogated to determine the directory tree below its location. 

The program then builds an ASCII array containing the full path to each subdirectory 

containing the data ensembles to be processed. Once completed, the program then copies 

the Trigger File for the first ensemble and overwrites the Trigger File specified in the 

entry screen. This will in turn trigger the Signal/Data Processing program to begin 

processing the data ensemble listed within the Trigger File. Once the ensemble is 

processed, the Signal/Data Processing program will update the Trigger.Ret File which, in 

turn commands the BatchLVprocessing program to select the Trigger File for the next data 

ensemble, and the process continues until the final ensemble is processed. At that point, 

termination commands are issued for both programs.

The data entry screen presented to the user is shown in Figure E-2. Description of the 

entry is:

Copy Trigger File to:

Click on the box and the program will open its file manager where the trigger file 

that will be used by the Signal / Data Processing program should be located and 

selected.

Appendix E.9
ConvertBinary2ASCII

This program will convert the binary data sent to the Signal / Data Processing program by 

the Data Acquisition program into ASCII format. The program can be used to generate 

files that can be used to interrogate, plot, etc. the signals obtained by the laser velocimeter. 

Once started the program will present an interface screen, Figure E-3, where the user can 

locate the desired trigger file for the ensemble of interest. Once the trigger file has been 

selected using the program's file manager (obtained by clicking the Trigger File: box), the 

Run box is clicked to start the conversion. A sub-directory will be created (ASCII) and 

attached to the directory containing the selected trigger file. This sub-directory will 

contain all of the ensemble files in ASCII format. When the ensemble has been converted, 

the program will return to the data entry screen. Another trigger file can then be selected, 

or the program terminated by clicking the Exit box.

Appendix E.10
!Thursday, January 20, 2011 

!10:33:03 AM 

!Data Acquisition Parameters: 

!NI PXI-6120 LV Configuration Parameters: 

LVMultiFunc/ai0 !PXI-6120 Ch0 

LVMultiFunc/ai1 !PXI-6120 Ch1 

LVMultiFunc/ai2 !PXI-6120 Ch2 

LVMultiFunc/ai3 !PXI-6120 Ch3 

+/-2.0V !Vertical Range 

PFI7 !PXI-6120 Trigger Source 

PFI7 !PXI-6120 Analog Sample Clock Source 

!NI PXI-5152 LV Configuration Parameters: 

UComp!PXI-5152 Ch0 

VComp !PXI-5152 Ch1 

4.00 Vp-p !Vertical Range 

0.000000 !Vertical Offset 

10240 !Record Length 

1000000000.000000 !Sample Rate 

!Trigger Mode: 0(Immediate), 1(Software), 2(Digital), 3(Analog Edge), 4(Analog Window) 

3 !Trigger Mode 

VAL_EXTERNAL !Trigger Source: 

!Scan Rig Information: 

C:\Program Files (x86)\National Instruments\LabVIEW 8.6\user.lib\scan rig files\Scan_Grid_BART_Day2!

Scanner Control File Path 

!Scanner Comment 

This VI allows the user to generate a sequence of scan locations at which data is to be collected. Using 

the axis settings location information in counts is generated each time the Generate Scan Data 

button is selected. Generated data is placed in the acti

 

0.0000390000 !Scan Rig Step Resolution - Inches (Distance/Step) 

!Scanner Positions In Counts: 

0.000000 !W-Axis 

0.000000 !X-Axis 

35000.500000 !Y-Axis 

-40000.000000 !Z-Axis 

!Scanner Positions In Inches: 

0.000000 !W-Axis 

0.000000 !X-Axis 

1.365020 !Y-Axis 

-1.560000 !Z-Axis 

Scanner Positions In Meters: 

0.000000 !W-Axis 

0.000000 !X-Axis 

0.034671 !Y-Axis 

-0.039624 !Z-Axis 

!Data Acquisition Conditions:: 

25.000000 !Temperature (C) 

30.000000 !Atm. Pressure (in/Hg) 

1.000000 !Particle Size 

Polystyrene !Particle Type 

!Data Acquisition Results:

Table E.1.- Example LOG file created by the signal/data processing program: Header. 

Appendix E.11
2000 !# LV Data Records Requested 

2000 !# LV Data Records Acquired 

12.829102 !LV Data Acquistion Cycle Time 

152.076121 !LV Data Acquistion Data Rate 

0 !Acquisition Cycle Timeout? 0=No, 1=Yes 

0 !User Terminated Acquisition? 0=No, 1=Yes 

!Running Plots Code 

RUN !Code to Control Plotting of Processed Data. NEW = New measurement scan, RUN = Append 

processed results to existing running plot. 

 

User Comment: Comments 

---------- 

------------------

0.4880 Laser wavelength - U-component, microns

0.5145 Laser wavelength - V-component, microns

3.5500 Cross beam angle - U-component, degrees

3.5500 Cross beam angle - V-component, degrees

40.0000 Bragg frequency - U-component, MHz

40.0000 Bragg frequency - V-component, MHz

0.0000 Reference frequency-downmixer - U-component, MHz

0.0000 Reference frequency-downmixer - V-component, MHz

0.0000 Azimuth increment, degrees

 2000 Number of particles in data ensemble

NOTE: N or Norm - Standard arithmetic statistics

 S/H - Based on Sample and Hold Approach

 TS - Based on Time Scale Approach

 Velocity & Standard Deviation Convergence

# Bursts U-mean U-sigma V-mean V-sigma Delta U Delta U Delta V Delta V 

 sigma sigma

 92 17.213 6.852 -1.663 5.672

 186 16.551 7.334 -1.323 5.855 -0.662 0.482 0.340 0.184

 281 16.544 7.047 -1.390 6.015 -0.007 -0.288 -0.066 0.160

 376 16.210 7.136 -1.307 5.834 -0.334 0.089 0.082 -0.181

 475 16.206 7.277 -1.290 5.832 -0.004 0.141 0.018 -0.002

 568 16.374 7.452 -1.351 5.816 0.168 0.175 -0.062 -0.016

 662 16.598 7.601 -1.540 5.826 0.224 0.149 -0.189 0.011

 756 16.567 7.529 -1.603 5.873 -0.031 -0.072 -0.063 0.047

 854 16.465 7.493 -1.627 5.802 -0.103 -0.036 -0.024 -0.072

 946 16.607 7.490 -1.680 5.847 0.142 -0.003 -0.053 0.045

 1044 16.596 7.441 -1.654 5.854 -0.011 -0.048 0.026 0.007

 1142 16.639 7.509 -1.622 5.840 0.043 0.067 0.032 -0.014

 1235 16.525 7.519 -1.603 5.879 -0.114 0.010 0.019 0.038

 1330 16.332 7.459 -1.512 5.859 -0.193 -0.060 0.091 -0.020

 1426 16.384 7.413 -1.528 5.882 0.051 -0.046 -0.016 0.023

 1520 16.375 7.427 -1.471 5.861 -0.009 0.014 0.058 -0.021

Table E.1. (cont'd) - Example LOG file: Header (cont'd) and statistical stationarity test.

Appendix E.12
 1610 16.330 7.365 -1.390 5.846 -0.045 -0.062 0.081 -0.015

 1702 16.359 7.308 -1.404 5.821 0.029 -0.057 -0.015 -0.025

 1797 16.403 7.317 -1.404 5.814 0.044 0.009 0.000 -0.007

 1894 16.321 7.324 -1.386 5.819 -0.082 0.006 0.018 0.006

Measurement Statistics

Correlation Coefficient 0.003

CorTime, #CorTime, #part: 0.000161 1483 1894

U-component Mean ? Mean Sigma ? Sigma Skew Excess

 m/s m/s m/s m/s

Normal Stats 16.321 0.337 7.324 0.235 0.021 -0.050

Sample & Hold 17.216 7.699 17.216 0.002 1.000 -2.000

Time Scale 24.948 12.489 25.374 2.299 1.050 -1.864

V-component Mean ? Mean Sigma ? Sigma Skew Excess

 m/s m/s m/s m/s

Normal Stats -1.386 0.267 5.819 0.181 -0.298 -0.161

Sample & Hold -0.237 0.106 0.237 NaN -1.000 -2.000

Time Scale 2.721 1.352 4.061 0.656 0.268 -1.058

Reynolds stress: -22.730665 m2/s2

Magnitude Mean ? Mean Sigma ? Sigma Skew Excess

 m/s m/s m/s m/s

Normal Stats 17.529 0.320 6.967 0.210 0.375 -0.279

Sample & Hold 17.218 7.700 17.218 0.001 1.000 -2.000

Time Scale 25.230 12.376 25.621 2.246 1.048 -1.868

Flow Angle Mean ? Mean Sigma ? Sigma Skew Excess

 m/s m/s m/s m/s

Normal Stats 0.350 1.228 26.720 1.626 0.960 5.017

Sample & Hold -0.789 0.353 0.789 0.000 -1.000 -2.000

Time Scale 10.289 6.302 18.566 4.242 1.675 -0.188

Particle Velocity Measurements

 Time Azimuth U V Magnitude Alpha V min V max Transit

 seconds degrees m/s m/s m/s degrees V V microsec

 0.000000 35.859 10.679 4.436 11.564 22.555 -0.636 0.498 10.236

 0.002707 81.211 31.410 -3.995 31.663 -7.248 -0.498 0.464 10.220

 0.009842 -158.555 9.428 -5.160 10.747 -28.693 -0.722 0.498 10.239

 0.012200 -119.180 14.194 -1.355 14.258 -5.453 -0.516 0.430 10.239

 0.016126 -53.086 19.180 -7.975 20.772 -22.576 -0.653 0.498 10.231

 0.026127 115.312 23.836 -11.520 26.474 -25.795 -0.292 0.275 10.227

 0.041439 12.656 9.017 9.311 12.962 45.920 -0.516 0.413 10.228

 0.045880 87.539 19.772 -2.743 19.962 -7.899 -0.464 0.413 10.235

 0.053316 -147.305 19.679 5.804 20.517 16.434 -0.481 0.430 10.227

 0.064169 35.156 18.150 -14.633 23.314 -38.876 -0.292 0.223 10.234

 0.072378 173.320 20.041 0.095 20.041 0.271 -0.464 0.430 10.239

Table E.1. (cont'd) - Example LOG file: statistical stationarity (cont'd), statistical results, individual bursts.

Appendix E.13
 0.073890 -161.367 16.702 -3.682 17.103 -12.431 -0.172 0.155 10.237

 0.089708 104.766 22.979 0.176 22.980 0.440 -0.344 0.327 10.239

 0.097539 -123.398 20.320 -9.814 22.566 -25.780 -0.464 0.413 10.210

 0.115181 173.320 21.094 -2.865 21.288 -7.734 -0.327 0.258 10.217

 0.123574 -45.703 18.191 -5.553 19.020 -16.975 -0.584 0.430 10.203

 0.125180 -18.633 11.364 7.729 13.744 34.219 -0.584 0.464 10.219

 0.125665 -10.547 9.945 0.398 9.953 2.290 -0.584 0.464 10.209

 0.131736 91.758 13.326 4.927 14.208 20.292 -0.773 0.533 10.239

 0.144099 -60.469 24.716 -6.540 25.567 -14.821 -0.653 0.481 10.234

 0.147173 -8.789 19.265 1.795 19.348 5.323 -0.584 0.498 10.228

 0.153347 95.273 11.268 4.466 12.120 21.621 -0.773 0.619 10.230

 0.170228 19.336 22.153 1.250 22.188 3.229 -0.086 0.103 10.238

 0.180542 -167.344 21.453 1.766 21.525 4.705 -0.636 0.464 10.239

 0.184755 -96.328 6.347 0.638 6.379 5.739 -0.533 0.430 10.236

 0.191441 16.172 19.223 -0.147 19.224 -0.439 -0.842 0.567 10.229

 0.193522 50.977 16.098 3.147 16.403 11.062 -0.619 0.464 10.239

 0.198097 127.969 14.538 5.271 15.464 19.929 -0.447 0.413 10.183

 0.200118 162.070 21.511 -1.019 21.535 -2.712 -0.791 0.550 10.227

 0.202304 -161.367 21.347 -2.412 21.483 -6.446 -0.447 0.361 10.237

 0.206680 -87.539 4.426 0.400 4.444 5.163 -0.825 0.653 10.224

 0.232452 -14.062 6.842 12.740 14.461 61.761 -0.498 0.395 10.208

 0.235287 33.398 23.482 -16.144 28.496 -34.508 -0.309 0.258 10.237

 0.238675 90.703 20.507 -5.616 21.262 -15.315 -0.344 0.327 10.239

 0.250400 -72.070 16.994 -6.644 18.247 -21.353 -0.533 0.481 10.215

 0.252874 -30.586 24.380 -8.440 25.800 -19.096 -0.464 0.447 10.239

 0.255387 11.602 10.722 -0.095 10.723 -0.507 -0.103 0.103 10.232

 0.264485 164.883 9.671 -2.698 10.040 -15.590 -0.516 0.447 10.236

 0.266541 -160.664 18.329 -11.740 21.766 -32.641 -0.653 0.567 10.118

 0.268400 -129.375 21.034 -6.545 22.028 -17.286 -0.808 0.533 10.239

 0.269564 -109.688 11.546 -0.952 11.585 -4.712 -0.172 0.189 10.162

 0.269874 -104.766 11.989 7.010 13.888 30.316 -0.705 0.584 10.239

 0.271258 -81.211 23.974 -6.028 24.720 -14.114 -0.481 0.430 10.238

 0.274293 -30.234 10.205 -2.550 10.519 -14.028 -0.361 0.309 10.239

 0.276920 13.711 15.392 -1.678 15.483 -6.221 -0.773 0.533 10.239

 0.278635 42.891 5.163 2.768 5.859 28.198 -0.791 0.567 10.239

 0.278941 47.812 7.102 -2.465 7.517 -19.144 -0.773 0.550 10.239

 0.282666 110.391 22.959 -12.861 26.316 -29.258 -0.705 0.516 10.239

 0.285969 165.938 28.508 -2.998 28.666 -6.004 -0.705 0.533 10.239

 0.286670 177.891 10.295 9.348 13.906 42.239 -0.550 0.430 10.239

 0.291776 -96.328 18.943 -6.307 19.965 -18.414 -0.756 0.602 10.239

 0.293937 -59.766 6.579 2.352 6.986 19.670 -0.275 0.258 10.238

 0.294682 -47.461 22.451 -2.489 22.589 -6.327 -0.481 0.395 10.228

 0.295612 -31.641 32.201 -3.407 32.381 -6.039 -0.653 0.498 10.236

 0.299025 25.664 16.718 0.035 16.718 0.120 -0.636 0.498 10.239

 0.306843 157.148 15.374 4.522 16.025 16.391 -0.172 0.172 10.236

 0.307593 169.805 18.228 -2.764 18.437 -8.623 -0.808 0.584 10.208

 0.309756 -153.633 18.022 0.882 18.044 2.800 -0.636 0.481 10.198

 0.314294 -77.344 29.679 -6.064 30.292 -11.548 -0.773 0.498 10.239

 0.316074 -47.461 6.330 7.140 9.542 48.444 -0.275 0.206 10.235

 0.316671 -37.617 19.867 -0.929 19.889 -2.676 -0.825 0.584 10.226

 0.318161 -12.305 13.635 0.444 13.642 1.863 -0.378 0.292 10.238

Table E.1. (cont'd) - Example LOG file: individual bursts.

Appendix E.14
 0.319844 15.820 25.302 -7.472 26.382 -16.452 -0.688 0.533 10.226

 0.320720 30.586 28.891 -7.061 29.741 -13.733 -0.653 0.567 10.183

 0.321352 41.133 16.194 3.424 16.552 11.939 -0.911 0.619 10.239

 0.322267 56.602 23.258 -7.045 24.301 -16.851 -0.327 0.275 10.239

 0.323941 84.727 12.206 9.461 15.443 37.779 -0.344 0.309 10.239

 0.326445 126.914 20.361 -8.780 22.174 -23.326 -0.241 0.223 10.239

 0.328154 155.742 20.308 -2.826 20.504 -7.922 -0.688 0.602 10.239

 0.328833 166.992 13.258 -1.525 13.345 -6.561 -0.825 0.619 10.227

 0.329275 174.375 26.739 -10.398 28.690 -21.249 -0.636 0.464 10.239

 0.330742 -160.664 8.383 4.660 9.591 29.066 -0.395 0.361 10.237

 0.331777 -143.438 25.623 -3.681 25.886 -8.176 -0.722 0.481 10.239

 0.332352 -133.594 15.616 -1.351 15.674 -4.943 -0.773 0.584 10.239

 0.332972 -123.398 8.400 1.969 8.628 13.194 -0.670 0.533 10.239

 0.335148 -86.484 10.411 2.653 10.743 14.296 -0.533 0.447 10.239

 0.337177 -52.383 7.555 1.611 7.725 12.040 -0.705 0.584 10.213

 0.338038 -37.969 16.085 1.971 16.206 6.984 -0.430 0.344 10.239

 0.338874 -23.906 7.570 2.120 7.861 15.647 -0.739 0.550 10.215

 0.339700 -10.195 27.888 -10.433 29.775 -20.511 -0.756 0.567 10.239

 0.341405 18.633 20.979 -1.376 21.024 -3.753 -0.653 0.533 10.239

 0.346636 106.523 9.088 -1.204 9.167 -7.544 -0.670 0.516 10.229

 0.347784 125.859 12.810 -1.604 12.910 -7.136 -0.395 0.327 10.187

 0.348777 142.734 18.352 0.407 18.357 1.270 -0.602 0.481 10.237

 0.349718 158.555 28.929 -6.249 29.596 -12.190 -0.911 0.584 10.236

 0.352575 -153.633 20.711 -6.884 21.825 -18.387 -0.464 0.378 10.226

 0.353516 -137.812 24.529 -7.702 25.710 -17.433 -0.739 0.533 10.233

 0.354713 -117.422 5.889 7.927 9.875 53.395 -0.859 0.619 10.239

 0.355937 -97.031 11.901 -1.056 11.948 -5.071 -0.498 0.413 10.239

 0.358337 -56.602 31.513 -10.623 33.255 -18.629 -0.361 0.327 10.239

 0.358582 -52.383 17.038 -2.021 17.158 -6.763 -0.756 0.619 10.239

 0.359438 -37.969 19.038 0.061 19.038 0.183 -0.447 0.413 10.239

 0.005510 -25.664 35.465 -8.043 36.365 -12.778 -0.413 0.344 10.239

 0.006784 -4.219 16.119 -8.894 18.410 -28.890 -0.567 0.481 10.202

 0.007393 5.977 22.185 4.874 22.714 12.391 -0.842 0.602 10.236

 0.008426 23.203 27.913 -4.215 28.229 -8.588 -0.447 0.395 10.239

 0.012239 87.539 20.533 -12.151 23.859 -30.615 -0.602 0.498 10.239

 0.012494 91.758 12.088 1.160 12.143 5.482 -0.756 0.533 10.239

 0.013274 104.766 19.895 -9.965 22.251 -26.607 -0.825 0.584 10.225

 0.014399 123.750 17.986 -0.718 18.000 -2.287 -0.722 0.498 10.229

 0.015213 137.461 19.647 -5.120 20.303 -14.606 -0.653 0.464 10.209

 0.015598 143.789 17.035 -6.387 18.193 -20.552 -0.430 0.413 10.239

 0.016387 157.148 6.849 0.042 6.849 0.348 -0.567 0.533 10.234

 0.017110 169.453 16.492 -7.550 18.138 -24.599 -0.481 0.447 10.239

 0.019514 -150.117 2.384 8.366 8.699 74.097 -0.223 0.189 10.223

 0.020239 -138.164 17.760 -2.743 17.971 -8.780 -0.911 0.722 10.228

 0.020967 -125.859 4.953 5.449 7.364 47.728 -0.584 0.533 10.219

 0.025155 -55.195 14.968 -1.015 15.002 -3.878 -0.842 0.584 10.239

 0.030746 38.672 2.291 9.424 9.699 76.336 -0.825 0.670 10.239

 0.030993 42.891 0.871 12.352 12.382 85.968 -0.309 0.275 10.227

 0.031987 59.414 16.075 -13.458 20.965 -39.937 -0.550 0.430 10.239

 0.033295 81.562 0.272 12.569 12.572 88.762 -0.825 0.584 10.238

 0.034303 98.438 6.255 2.510 6.740 21.863 -0.361 0.344 10.239

Table E.1. (cont'd) - Example LOG file: individual bursts (cont'd).

Appendix E.15
 0.036857 141.328 11.678 5.831 13.053 26.535 -0.791 0.567 10.239

 0.037282 148.711 22.080 -6.935 23.143 -17.437 -0.877 0.636 10.233

 0.039281 -177.891 7.500 -6.884 10.180 -42.550 -0.911 0.584 10.239

 0.040332 -159.961 20.974 4.173 21.385 11.253 -0.859 0.602 10.239

 0.041321 -143.438 15.072 5.332 15.987 19.481 -0.223 0.206 10.216

 0.042193 -128.672 4.013 -5.384 6.715 -53.298 -0.378 0.309 10.239

 0.046837 -50.625 24.888 -6.361 25.688 -14.337 -0.533 0.447 10.239

 0.047304 -42.891 6.071 6.694 9.037 47.794 -0.619 0.498 10.237

 0.048449 -23.555 15.319 -6.502 16.642 -23.000 -0.327 0.292 10.239

 0.049994 2.461 12.088 1.919 12.240 9.023 -0.705 0.516 10.239

 0.050883 17.578 25.665 0.611 25.672 1.363 -0.413 0.395 10.239

 0.051721 31.641 16.007 -4.431 16.608 -15.472 -0.361 0.344 10.231

 0.055396 93.164 -3.471 7.149 7.947 115.898 -0.859 0.619 10.239

 0.059751 166.641 14.484 -6.648 15.937 -24.653 -0.688 0.481 10.238

 0.064164 -119.180 18.140 4.839 18.775 14.937 -0.602 0.516 10.218

 0.069711 -26.016 20.605 -8.337 22.228 -22.030 -0.894 0.636 10.239

 0.073762 42.188 20.429 6.077 21.314 16.567 -0.894 0.670 10.237

 0.075015 63.281 14.610 1.319 14.669 5.158 -0.636 0.498 10.239

 0.075522 71.719 17.293 -1.167 17.332 -3.859 -0.584 0.481 10.225

 0.077697 108.633 2.821 -3.368 4.393 -50.044 -0.361 0.309 10.239

 0.078803 126.914 22.814 -5.261 23.413 -12.986 -0.464 0.464 10.221

 0.083482 -154.336 9.074 2.418 9.391 14.921 -0.550 0.447 10.239

 0.084096 -143.789 7.912 6.713 10.376 40.312 -0.120 0.103 10.235

 0.086068 -110.742 3.164 8.394 8.971 69.345 -0.636 0.464 10.239

 0.087243 -91.055 11.452 2.340 11.689 11.547 -0.498 0.378 10.239

 0.087803 -81.562 6.901 4.809 8.411 34.873 -0.894 0.602 10.237

 0.090905 -29.531 9.135 -9.220 12.979 -45.264 -0.550 0.481 10.239

 0.091587 -17.930 23.356 -3.590 23.631 -8.737 -0.395 0.395 10.239

 0.093072 7.031 12.223 -11.310 16.653 -42.780 -0.705 0.464 10.239

 0.093335 11.602 3.959 -1.528 4.244 -21.097 -0.223 0.189 10.229

 0.095316 45.000 19.352 7.520 20.761 21.235 -0.739 0.516 10.237

 0.096365 62.578 21.560 -14.853 26.181 -34.562 -0.842 0.584 10.239

 0.097041 73.828 17.761 6.843 19.033 21.073 -0.550 0.533 10.239

 0.099283 111.445 13.966 0.556 13.977 2.280 -0.378 0.378 10.239

 0.099856 121.289 24.956 -0.226 24.957 -0.519 -0.344 0.327 10.239

 0.100645 134.297 8.992 8.316 12.248 42.764 -0.395 0.344 10.239

 0.105973 -136.055 18.554 -0.087 18.554 -0.268 -0.464 0.430 10.222

 0.106820 -121.641 8.196 0.908 8.246 6.323 -0.533 0.413 10.235

 0.107630 -107.930 31.583 2.647 31.694 4.792 -0.688 0.533 10.239

 0.107955 -102.656 26.640 0.259 26.642 0.556 -0.739 0.550 10.239

 0.108736 -89.297 26.128 -13.051 29.206 -26.542 -0.498 0.464 10.187

 0.111825 -37.617 15.701 0.220 15.703 0.803 -0.292 0.275 10.236

 0.112273 -29.883 20.605 -0.732 20.618 -2.034 -0.619 0.464 10.229

 0.113378 -11.250 19.364 -4.339 19.844 -12.630 -0.859 0.602 10.239

 0.113794 -4.219 16.738 -1.244 16.784 -4.251 -0.430 0.344 10.239

 0.114673 10.547 14.511 -2.025 14.652 -7.944 -0.378 0.309 10.239

 0.116314 37.969 28.320 -5.779 28.903 -11.534 -0.516 0.481 10.236

 0.116814 46.406 26.739 -7.238 27.701 -15.146 -0.481 0.395 10.239

 0.117768 62.578 11.782 2.180 11.982 10.484 -0.567 0.498 10.239

 0.119004 83.320 19.918 4.337 20.385 12.285 -0.825 0.584 10.239

 0.119367 89.297 20.466 -0.639 20.476 -1.789 -0.258 0.241 10.238

Table E.1. (cont'd) - Example LOG file: individual bursts (cont'd).

Appendix E.16
 0.120107 101.953 15.990 5.124 16.791 17.767 -0.550 0.447 10.239

 0.121178 119.883 12.432 -0.890 12.463 -4.097 -0.395 0.447 10.231

 0.121959 132.891 12.952 2.206 13.139 9.666 -0.791 0.584 10.239

 0.123978 166.992 7.712 2.991 8.272 21.197 -0.481 0.430 10.232

 0.124556 176.836 30.146 -9.501 31.608 -17.493 -0.619 0.430 10.230

 0.125263 -171.562 22.016 -6.181 22.867 -15.682 -0.825 0.584 10.239

 0.126000 -158.906 13.449 3.229 13.832 13.502 -0.825 0.653 10.236

 0.129089 -107.227 28.392 -12.253 30.923 -23.344 -0.498 0.447 10.237

 0.130402 -85.078 20.461 -5.351 21.150 -14.655 -0.808 0.653 10.193

 0.131202 -71.367 11.454 1.123 11.509 5.597 -0.808 0.567 10.238

 0.133136 -39.023 20.382 -4.213 20.813 -11.678 -0.413 0.361 10.237

 0.133657 -30.234 12.072 1.714 12.194 8.079 -0.447 0.430 10.222

 0.136513 17.930 18.036 0.050 18.036 0.159 -0.498 0.378 10.233

 0.136799 22.500 15.336 -3.264 15.680 -12.016 -0.602 0.447 10.233

 0.137854 40.430 11.934 2.532 12.200 11.976 -0.670 0.498 10.239

 0.138358 48.867 12.046 -1.701 12.165 -8.035 -0.791 0.584 10.239

 0.139057 60.469 18.232 -0.525 18.240 -1.648 -0.773 0.567 10.225

 0.140353 82.266 18.182 2.884 18.409 9.014 -0.395 0.395 10.238

 0.140932 92.109 13.853 0.984 13.888 4.065 -0.533 0.516 10.239

 0.141865 107.930 18.641 1.255 18.683 3.851 -0.241 0.189 10.236

 0.142433 117.422 26.559 -6.570 27.360 -13.895 -0.584 0.550 10.236

 0.143933 142.734 28.452 -8.550 29.709 -16.725 -0.653 0.516 10.239

 0.006439 166.289 22.305 2.606 22.457 6.663 -0.773 0.481 10.238

 0.006841 172.969 17.421 -9.357 19.774 -28.240 -0.378 0.327 10.239

 0.007895 -169.102 25.926 -3.377 26.145 -7.422 -0.808 0.533 10.239

 0.008434 -159.961 15.559 -0.233 15.561 -0.856 -0.808 0.619 10.217

 0.009324 -145.195 16.716 2.924 16.970 9.920 -0.756 0.533 10.235

 0.010049 -132.891 24.087 -7.446 25.211 -17.178 -0.309 0.292 10.238

 0.010655 -122.695 15.484 -0.729 15.501 -2.697 -0.619 0.464 10.238

 0.011663 -105.820 32.429 -10.583 34.112 -18.074 -0.464 0.447 10.219

 0.012295 -95.273 16.786 -5.835 17.771 -19.167 -0.498 0.430 10.239

 0.013230 -79.453 30.876 -8.710 32.081 -15.753 -0.808 0.584 10.236

 0.013969 -67.148 21.199 -2.669 21.366 -7.177 -0.619 0.498 10.239

 0.014947 -50.625 20.632 2.211 20.750 6.117 -0.894 0.670 10.239

 0.015436 -42.188 10.669 4.498 11.578 22.860 -0.413 0.361 10.239

 0.016821 -18.984 19.385 -7.389 20.745 -20.866 -0.172 0.189 10.225

 0.018966 17.227 21.153 -6.122 22.021 -16.142 -0.722 0.584 10.238

 0.019604 27.773 16.658 -5.224 17.458 -17.413 -0.722 0.550 10.235

 0.020018 34.805 16.686 -4.516 17.287 -15.144 -0.413 0.430 10.239

 0.021300 56.250 9.825 5.929 11.476 31.110 -0.619 0.516 10.237

 0.021650 62.227 16.605 -4.425 17.185 -14.922 -0.842 0.567 10.238

 0.022980 84.727 16.231 5.862 17.257 19.857 -0.430 0.413 10.239

 0.023732 97.383 25.743 -1.680 25.798 -3.734 -0.481 0.447 10.238

 0.024193 105.117 18.328 -6.935 19.596 -20.725 -0.378 0.327 10.232

 0.024799 115.312 22.917 3.799 23.230 9.412 -0.688 0.567 10.239

 0.026374 141.680 13.737 -1.288 13.797 -5.355 -0.481 0.413 10.239

 0.027957 168.398 6.808 1.248 6.921 10.389 -0.825 0.533 10.232

 0.028950 -175.078 9.750 3.240 10.275 18.384 -0.739 0.567 10.237

 0.030347 -151.523 32.099 -5.697 32.601 -10.063 -0.516 0.481 10.239

 0.031235 -136.406 13.570 -2.158 13.741 -9.036 -0.138 0.138 10.239

 0.032522 -114.961 22.283 -9.403 24.186 -22.879 -0.447 0.413 10.198

Table E.1. (cont'd) - Example LOG file: individual bursts (cont'd).

Appendix E.17
 0.033020 -106.523 22.496 -0.867 22.512 -2.207 -0.516 0.464 10.222

 0.034791 -76.641 12.145 -1.904 12.293 -8.910 -0.464 0.378 10.238

 0.035836 -59.062 13.898 3.367 14.300 13.617 -0.791 0.584 10.239

 0.036794 -42.891 15.396 2.063 15.534 7.632 -0.670 0.498 10.239

 0.037204 -36.211 16.764 -1.249 16.811 -4.259 -0.877 0.636 10.232

 0.038161 -20.039 8.084 9.484 12.462 49.556 -0.705 0.550 10.238

 0.039704 5.977 11.746 8.369 14.422 35.469 -0.498 0.378 10.220

 0.040720 22.852 24.640 0.453 24.644 1.054 -0.602 0.567 10.238

 0.042373 50.625 15.038 1.953 15.164 7.401 -0.791 0.670 10.239

 0.042774 57.656 9.200 9.223 13.027 45.074 -0.172 0.172 10.228

 0.044974 94.570 12.923 1.465 13.006 6.467 -0.739 0.550 10.238

 0.046027 112.148 12.175 -2.399 12.409 -11.145 -0.533 0.464 10.239

 0.048515 153.984 17.770 -3.367 18.086 -10.729 -0.808 0.550 10.239

 0.050825 -166.992 14.880 3.548 15.298 13.411 -0.138 0.172 10.222

 0.051173 -161.016 8.382 5.952 10.280 35.378 -0.688 0.533 10.231

 0.053167 -127.617 5.426 1.762 5.705 17.992 -0.808 0.584 10.239

 0.055897 -81.562 5.136 12.100 13.145 66.999 -0.825 0.653 10.235

 0.056327 -74.531 19.595 1.345 19.641 3.926 -0.739 0.602 10.239

 0.058902 -31.289 14.394 -3.847 14.899 -14.962 -0.842 0.567 10.239

 0.059608 -19.336 19.460 -9.540 21.673 -26.114 -0.498 0.447 10.239

 0.061472 11.953 7.251 4.294 8.427 30.637 -0.275 0.275 10.239

 0.062881 35.859 22.370 -10.646 24.774 -25.449 -0.602 0.516 10.222

 0.064656 65.742 15.004 4.375 15.629 16.256 -0.619 0.481 10.239

 0.065537 80.508 22.308 -12.438 25.541 -29.142 -0.223 0.189 10.239

 0.065973 87.891 26.730 -4.932 27.181 -10.454 -0.825 0.584 10.239

 0.066673 99.492 16.572 -6.594 17.835 -21.698 -0.567 0.464 10.229

 0.067487 113.203 27.834 -12.919 30.686 -24.898 -0.722 0.550 10.236

 0.068499 130.430 17.315 2.930 17.561 9.604 -0.413 0.378 10.239

 0.069519 147.305 12.516 -14.053 18.818 -48.312 -0.447 0.378 10.239

 0.070635 166.289 -1.500 10.840 10.943 97.879 -0.361 0.309 10.239

 0.071917 -172.266 27.738 -1.561 27.782 -3.222 -0.155 0.138 10.239

 0.074965 -120.938 15.026 -9.172 17.604 -31.398 -0.653 0.567 10.211

 0.075363 -114.258 22.474 -14.096 26.529 -32.097 -0.670 0.533 10.239

 0.078123 -67.852 25.990 -13.363 29.224 -27.210 -0.602 0.481 10.239

 0.078753 -57.305 13.993 0.402 13.999 1.646 -0.722 0.516 10.239

 0.079207 -49.570 12.967 -7.019 14.745 -28.426 -0.550 0.430 10.239

 0.080083 -34.805 7.935 5.035 9.397 32.397 -0.705 0.550 10.140

 0.081898 -4.219 18.805 -3.387 19.107 -10.212 -0.756 0.533 10.205

 0.082107 -0.703 19.197 -13.634 23.546 -35.383 -0.516 0.395 10.238

 0.085712 59.766 12.682 2.022 12.843 9.057 -0.825 0.567 10.239

 0.086417 71.719 13.058 10.133 16.528 37.813 -0.756 0.602 10.239

 0.087501 90.000 12.423 -3.876 13.013 -17.327 -0.584 0.498 10.239

 0.088119 100.195 11.150 -1.730 11.284 -8.822 -0.584 0.498 10.239

 0.088932 113.906 12.077 -11.747 16.848 -44.207 -0.378 0.344 10.228

 0.090109 133.945 21.598 -4.968 22.162 -12.954 -0.670 0.481 10.235

 0.091689 160.312 18.237 -6.643 19.409 -20.014 -0.722 0.584 10.239

 0.092460 173.320 25.360 -14.319 29.123 -29.450 -0.688 0.516 10.194

 0.092976 -177.891 10.457 2.485 10.748 13.369 -0.602 0.481 10.232

 0.094101 -158.906 24.931 -2.866 25.095 -6.558 -0.430 0.430 10.238

 0.094685 -149.414 24.198 -2.639 24.341 -6.224 -0.481 0.481 10.234

 0.097360 -104.414 14.994 -5.784 16.071 -21.093 -0.481 0.430 10.236

Table E.1. (cont'd) - Example LOG file: individual bursts (cont'd).

Appendix E.18
 0.098252 -89.297 21.833 -0.249 21.835 -0.652 -0.292 0.241 10.239

 0.100449 -52.383 8.748 5.521 10.345 32.257 -0.447 0.395 10.232

 0.101980 -26.367 20.931 -4.743 21.462 -12.769 -0.722 0.516 10.237

 0.104333 13.008 19.705 -7.686 21.150 -21.308 -0.430 0.344 10.233

 0.105755 36.914 15.606 2.038 15.738 7.441 -0.189 0.155 10.207

 0.106922 56.602 11.848 2.674 12.146 12.718 -0.567 0.516 10.239

 0.107666 69.258 6.451 5.228 8.303 39.022 -0.619 0.516 10.236

 0.108352 80.508 16.045 7.112 17.550 23.905 -0.722 0.516 10.239

 0.109006 91.758 20.645 -5.492 21.363 -14.897 -0.464 0.430 10.238

 0.109685 103.008 7.687 2.512 8.087 18.093 -0.688 0.516 10.238

 0.110907 123.750 14.240 -2.283 14.422 -9.107 -0.705 0.516 10.238

 0.111207 128.672 13.011 4.009 13.615 17.126 -0.413 0.413 10.210

 0.112533 150.820 10.925 2.352 11.175 12.148 -0.602 0.516 10.237

 0.113666 170.156 7.669 7.042 10.412 42.561 -0.550 0.516 10.236

 0.114365 -178.242 11.965 6.983 13.853 30.269 -0.722 0.584 10.225

 0.006915 -166.289 16.611 -1.130 16.649 -3.893 -0.481 0.413 10.235

 0.007746 -152.227 6.717 6.295 9.206 43.145 -0.498 0.413 10.229

 0.008996 -131.133 15.812 -4.075 16.328 -14.451 -0.791 0.584 10.077

 0.011372 -91.406 17.145 -6.587 18.367 -21.017 -0.842 0.584 10.236

 0.012192 -77.695 14.030 8.202 16.252 30.312 -0.447 0.413 10.239

 0.014313 -41.836 14.195 -2.851 14.478 -11.356 -0.739 0.516 10.239

 0.015298 -25.312 8.476 -2.432 8.818 -16.008 -0.447 0.395 10.236

 0.015879 -15.469 21.570 -6.085 22.412 -15.754 -0.567 0.516 10.232

 0.016434 -6.328 9.126 10.908 14.222 50.082 -0.550 0.464 10.238

 0.018327 25.664 8.817 -0.865 8.859 -5.601 -0.464 0.395 10.238

 0.019469 45.000 17.175 -3.311 17.491 -10.913 -0.602 0.430 10.239

 0.019801 50.273 12.131 -0.994 12.172 -4.684 -0.498 0.413 10.235

 0.021445 78.047 14.617 -3.467 15.022 -13.344 -0.395 0.292 10.238

 0.021700 82.266 11.017 -3.336 11.511 -16.845 -0.481 0.378 10.239

Velocity Histograms

U U-count V V-count Magnitude Mag-count AlphaAlpha-count

 -12.000 0.000 -24.000 0.000 -9.000 0.000 -106.000 0.000

 -11.000 0.000 -23.000 0.000 -8.000 0.000 -105.000 1.000

 -10.000 0.000 -22.000 0.000 -7.000 0.000 -104.000 0.000

 -9.000 0.000 -21.000 2.000 -6.000 0.000 -103.000 0.000

 -8.000 1.000 -20.000 0.000 -5.000 0.000 -102.000 0.000

 -7.000 1.000 -19.000 4.000 -4.000 0.000 -101.000 0.000

 -6.000 0.000 -18.000 3.000 -3.000 0.000 -100.000 1.000

 -5.000 3.000 -17.000 6.000 -2.000 0.000 -99.000 1.000

 -4.000 2.000 -16.000 3.000 -1.000 0.000 -98.000 0.000

 -3.000 8.000 -15.000 12.000 0.000 0.000 -97.000 0.000

 -2.000 2.000 -14.000 16.000 1.000 1.000 -96.000 0.000

 -1.000 8.000 -13.000 22.000 2.000 4.000 -95.000 0.000

 0.000 7.000 -12.000 37.000 3.000 4.000 -94.000 0.000

 1.000 7.000 -11.000 37.000 4.000 14.000 -93.000 0.000

 2.000 13.000 -10.000 46.000 5.000 14.000 -92.000 1.000

Table E.1. (cont'd) - Example LOG file: individual bursts (cont'd), histograms.

Appendix E.19
 3.000 21.000 -9.000 44.000 6.000 31.000 -91.000 0.000

 4.000 17.000 -8.000 61.000 7.000 41.000 -90.000 0.000

 5.000 31.000 -7.000 67.000 8.000 62.000 -89.000 0.000

 6.000 32.000 -6.000 89.000 9.000 72.000 -88.000 0.000

 7.000 42.000 -5.000 94.000 10.000 71.000 -87.000 0.000

 8.000 80.000 -4.000 82.000 11.000 79.000 -86.000 0.000

 9.000 59.000 -3.000 143.000 12.000 91.000 -85.000 0.000

 10.000 75.000 -2.000 121.000 13.000 99.000 -84.000 0.000

 11.000 72.000 -1.000 125.000 14.000 103.000 -83.000 0.000

 12.000 94.000 0.000 129.000 15.000 102.000 -82.000 0.000

 13.000 95.000 1.000 108.000 16.000 108.000 -81.000 0.000

 14.000 104.000 2.000 137.000 17.000 108.000 -80.000 1.000

 15.000 100.000 3.000 120.000 18.000 102.000 -79.000 0.000

 16.000 113.000 4.000 99.000 19.000 88.000 -78.000 0.000

 17.000 96.000 5.000 72.000 20.000 101.000 -77.000 0.000

 18.000 95.000 6.000 66.000 21.000 87.000 -76.000 0.000

 19.000 94.000 7.000 51.000 22.000 72.000 -75.000 0.000

 20.000 98.000 8.000 37.000 23.000 62.000 -74.000 0.000

 21.000 86.000 9.000 26.000 24.000 55.000 -73.000 0.000

 22.000 67.000 10.000 16.000 25.000 57.000 -72.000 0.000

 23.000 58.000 11.000 9.000 26.000 52.000 -71.000 0.000

 24.000 57.000 12.000 6.000 27.000 40.000 -70.000 0.000

 25.000 46.000 13.000 3.000 28.000 28.000 -69.000 2.000

 26.000 41.000 29.000 32.000 -68.000 0.000

 27.000 38.000 30.000 29.000 -67.000 0.000

 28.000 29.000 31.000 17.000 -66.000 1.000

 29.000 21.000 32.000 21.000 -65.000 0.000

 30.000 21.000 33.000 17.000 -64.000 0.000

 31.000 21.000 34.000 9.000 -63.000 0.000

 32.000 15.000 35.000 6.000 -62.000 0.000

 33.000 8.000 36.000 9.000 -61.000 0.000

 34.000 7.000 37.000 3.000 -60.000 1.000

 35.000 5.000 38.000 0.000 -59.000 0.000

 36.000 2.000 39.000 1.000 -58.000 0.000

 37.000 0.000 -57.000 0.000

 38.000 1.000 -56.000 0.000

 -55.000 0.000

 -54.000 2.000

 -53.000 3.000

 -52.000 1.000

 -51.000 0.000

 -50.000 2.000

 -49.000 0.000

 -48.000 1.000

 -47.000 0.000

 -46.000 1.000

 -45.000 5.000

 -44.000 1.000

 -43.000 5.000

 -42.000 2.000

 -41.000 5.000

Table E.1. (cont'd) - Example LOG file: histograms (cont'd).

Appendix E.20
 -40.000 5.000

 -39.000 6.000

 -38.000 3.000

 -37.000 5.000

 -36.000 4.000

 -35.000 9.000

 -34.000 8.000

 -33.000 8.000

 -32.000 9.000

 -31.000 15.000

 -30.000 12.000

 -29.000 21.000

 -28.000 12.000

 -27.000 17.000

 -26.000 16.000

 -25.000 20.000

 -24.000 21.000

 -23.000 26.000

 -22.000 29.000

 -21.000 37.000

 -20.000 19.000

 -19.000 29.000

 -18.000 28.000

 -17.000 33.000

 -16.000 30.000

 -15.000 36.000

 -14.000 42.000

 -13.000 37.000

 -12.000 38.000

 -11.000 38.000

 -10.000 44.000

 -9.000 49.000

 -8.000 46.000

 -7.000 35.000

 -6.000 41.000

 -5.000 42.000

 -4.000 41.000

 -3.000 37.000

 -2.000 33.000

 -1.000 39.000

 0.000 48.000

 1.000 27.000

 2.000 28.000

 3.000 22.000

 4.000 18.000

 5.000 35.000

 6.000 38.000

 7.000 24.000

 8.000 22.000

 9.000 30.000

 10.000 29.000

Table E.1. (cont'd) - Example LOG file: histograms (cont'd).

Appendix E.21
 11.000 20.000

 12.000 30.000

 13.000 26.000

 14.000 19.000

 15.000 21.000

 16.000 20.000

 17.000 19.000

 18.000 13.000

 19.000 21.000

 20.000 18.000

 21.000 13.000

 22.000 11.000

 23.000 11.000

 24.000 11.000

 25.000 12.000

 26.000 9.000

 27.000 10.000

 28.000 18.000

 29.000 6.000

 30.000 11.000

 31.000 11.000

 32.000 9.000

 33.000 6.000

 34.000 10.000

 35.000 7.000

 36.000 5.000

 37.000 6.000

 38.000 10.000

 39.000 5.000

 40.000 1.000

 41.000 5.000

 42.000 3.000

 43.000 8.000

 44.000 3.000

 45.000 5.000

 46.000 3.000

 47.000 3.000

 48.000 6.000

 49.000 4.000

 50.000 5.000

 51.000 3.000

 52.000 2.000

 53.000 4.000

 54.000 1.000

 55.000 1.000

 56.000 0.000

 57.000 2.000

 58.000 4.000

 59.000 1.000

 60.000 2.000

 61.000 1.000

Table E.1. (cont'd) - Example LOG file: histograms (cont'd).

Appendix E.22
 62.000 1.000

 63.000 3.000

 64.000 3.000

 65.000 0.000

 66.000 3.000

 67.000 1.000

 68.000 2.000

 69.000 4.000

 70.000 1.000

 71.000 0.000

 72.000 0.000

 73.000 0.000

 74.000 1.000

 75.000 2.000

 76.000 2.000

 77.000 3.000

 78.000 0.000

 79.000 2.000

 80.000 1.000

 81.000 1.000

 82.000 0.000

 83.000 0.000

 84.000 1.000

 85.000 1.000

 86.000 1.000

 87.000 0.000

 88.000 1.000

 89.000 1.000

 90.000 0.000

 91.000 0.000

 92.000 1.000

 93.000 1.000

 94.000 0.000

 95.000 1.000

 96.000 0.000

 97.000 1.000

 98.000 2.000

 99.000 1.000

 100.000 0.000

 101.000 0.000

 102.000 1.000

 103.000 0.000

 104.000 1.000

 105.000 0.000

 106.000 1.000

 

Convergence: U-mean, U-sigma, V-mean, V-sigma, Convergence Avg

 0.0133 0.0196 0.0138 0.0082 0.0137

Table E.1. (cont'd) - Example LOG file: histograms (cont'd), statistical stationarity test convergence.

Appendix E.23
Figure E.1.- Set-up screen for the laser velocimeter signal/data processing program.

Appendix E.24
Figure E.2.- Set-up screen for the laser velocimeter batch processing program.

Appendix E.25
Figure E.3.- Set-up screen for the laser velocimeter binary to ASCII conversion program.

Appendix E.26
REPORT DOCUMENTATION PAGE Form Approved

OMB No. 0704-0188

2. REPORT TYPE 

Technical Memorandum

 4. TITLE AND SUBTITLE

14- by 22-Foot Subsonic Tunnel Laser Velocimeter Upgrade

5a. CONTRACT NUMBER

 6. AUTHOR(S)

Meyers, James F.; Lee, Joseph W.; Cavone, Angelo A.; Flecher, Mark T.

 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

NASA Langley Research Center

Hampton, VA 23681-2199

 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

 8. PERFORMING ORGANIZATION

 REPORT NUMBER

L-20201

10. SPONSOR/MONITOR'S ACRONYM(S)

NASA

13. SUPPLEMENTARY NOTES

12. DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified - Unlimited

Subject Category 35

Availability: NASA CASI (443) 757-5802

19a. NAME OF RESPONSIBLE PERSON

STI Help Desk (email: help@sti.nasa.gov)

14. ABSTRACT

A long-focal length laser velocimeter constructed in the early 1980's was upgraded using current technology to improve 

usability, reliability and future serviceability. The original, free-space optics were replaced with a state-of-the-art fiber-optic 

subsystem which allowed most of the optics, including the laser, to be remote from the harsh tunnel environment. General 

purpose high-speed digitizers were incorporated in a standard modular data acquisition system, along with custom signal 

processing software executed on a desktop computer, served as the replacement for the signal processors. The resulting system 

increased optical sensitivity with real-time signal/data processing that produced measurement precisions exceeding those of the

original system. Monte Carlo simulations, along with laboratory and wind tunnel investigations were used to determine system 

characteristics and measurement precision.

15. SUBJECT TERMS

Analog-to-digital converters; Laser velocimeters; Subsonic tunnel; Velocity measurements; Wind tunnel

instrumentation; Wind tunnel tests

18. NUMBER

 OF 

 PAGES

793

19b. TELEPHONE NUMBER (Include area code)

(443) 757-5802

a. REPORT

U

c. THIS PAGE

U

b. ABSTRACT

U

17. LIMITATION OF 

 ABSTRACT

UU

Prescribed by ANSI Std. Z39.18

Standard Form 298 (Rev. 8-98)

3. DATES COVERED (From - To)

October 2009 - July 2012 

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

5d. PROJECT NUMBER

5e. TASK NUMBER

5f. WORK UNIT NUMBER

380046.02.07.03.03.01

11. SPONSOR/MONITOR'S REPORT

 NUMBER(S)

NASA/TM-2012-217781

16. SECURITY CLASSIFICATION OF:

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, 

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this 

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shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.

1. REPORT DATE (DD-MM-YYYY)

01- 11 - 2012