SOLUTION SHEETEduPIV & EduStereoPIV

LED-Based Educational Particle Image Velocimetry Systems

EduPIV and EduStereoPIV - turnkey PIV systems for educational use.

Turnkey PIV systems for educational use

Particle Imaging Velocimetry (PIV) systems allow for non-intrusive optical measurementsof velocity fields in flows. Historically, PIV has been out of reach for most educational
laboratories due to cost and, more importantly, laser-safety concerns.
The EduPIV series consists of systems for planar PIV and Stereo PIV. They offer a safe,
affordable, and turnkey solution for introducing students to this powerful technique.
These systems employ an LED-based illumination source which is safe and easy to operate
while combining excellent reliability and performance. Complete with all necessary
hardware, software, and table-top flow experiment, the EduPIV and EduStereoPIV systems
can carry out simple and advanced PIV experiments and demonstrations without the needfor any additional equipment other than a computer.
For data acquisition, image processing, and flow analysis, the system comes with
DynamicStudio EduPIV software to provide students with all the latest tools for PIV.

Key benefits•

Time resolved PIV measurements for fluid mechanics laboratory courses•

Planar PIV and Stereo PIV solutions available•

Upgrade possibility from EduPIV to EduStereoPIV and to more advanced systems•

Student training - prepare students for PIV research during and after university•

Safe operation with LED illumination – no laser required•

Powerful DynamicStudio EduPIV software offers students a comprehensive PIV experience•

Complete flow-loop and experiment with instructional video•

Simple, flexible flow loop design; easy to add student-created experiments

The EduPIV and EduStereoPIV solutions in brief
Particle Image Velocimetry (PIV) is a non-intrusive optical measurement
technique for research and diagnostics into flow, turbulence, microfluidics,
spray atomization, and combustion processes. A fluid is seeded with small
particles that follow the fluid’s motion. The particles are illuminated andcaptured via at least one camera. The fluid motion is subsequently analyzed
using PIV software. Standard 2D2C PIV (2 Dimensions, 2 Components) usesa single camera and measures two velocity components in the illuminatedplane. Typically, these systems consist of a camera, a laser with some beam
guiding components, light sheet optics, a synchronizer, and a PC for dataacquisition, storage, and analysis.
In case of a Stereo PIV (2D3C) system, a second camera and a calibration
target are required which are used to project the planar vectors in theillumination plane into the 3rd dimension.
For both systems, an LED illumination source and fiber optics are usedrather than a laser, and the image timing is controlled entirely by camera
settings in the DynamicStudio software. The configuration of the system
makes it safe and simple to operate, allowing students to focus on learning
measurement principles rather than on operating complex hardware.
A complete experimental setup and measurement system is included toprovide a turnkey solution for PIV instruction. The basis of the flow setup
is a water tank experiment (flow loop) with a variable pump and nozzle.
The nozzle produces a water jet which allows for a variety of tests to be
carried out, and the flow loop can be easily reconfigured for additional tests.
Micron-sized polyamide spheres are used for seeding the jet flow, and one
or two FlowSense USB 2M-165 camera capture the particle motion. Theimages are analyzed using DynamicStudio to provide global velocity maps,
turbulence statistics, scalar analysis, temporal/spectral evaluation, and flow
visualization.

Overview of the different components, timing and data flow

EduPIV Flow Loop Experiment
The flow loop consists of a water tank on a table-top aluminum frame witha sliding arm mount for the camera and light sheet optics. The LED andsheet optics illuminate the measurement plane and the sliding arm moves
the camera and light sheet together for imaging different areas of theflow. The included pump and nozzle provide a jet flow with variable output
controlled by an electronic controller. The water jet can be operated in thefollowing modes:
Steady Flow: This is the first and most basic flow used to teach students
the fundamentals of the PIV method. It consists of a quasi-steady, turbulent
jet flow. Providing a simple (primarily) unidirectional flow allowing students
to start by focusing on the PIV method rather than the flow complications.
Here, students learn the basic parameters for carrying out PIV experiments:
timing, seeding, camera setup, and illumination basics. Flow speed isvariable up to approximately 50 cm/s with the supplied nozzle. Higher/
lower velocities can be achieved using different nozzles.
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2-Level Calibration Target for easy, fast,and accurate spatial calibrations.

3D-printed nozzle.

Periodic Flow: The jet velocity fluctuates periodically to create a dynamic
jet flow. This allows students to do temporal, spectral, and modal analysis.
More consideration of PIV parameters is introduced to account for the larger
variations in velocity.

DynamicStudio
The DynamicStudio EduPIV software links acquisition, data processing, andresults analysis together in a powerful user interface. To calculate the velocity
fields from acquired raw images and analyze the results, the DynamicStudioBase package and add-on for 2D2C PIV analysis are used.
The EduPIV system includes our powerful DynamicStudio EduPIV software
to provide students real-world PIV experience with the most advanced
processing techniques available for 2D2C PIV and Stereo PIV. With dataacquisition and analysis performed in the same software, there is no needto move data around. Dedicated analysis routines and customized analysis
sequences allow for quick investigation and visualization of results. Thesoftware is very easy to use and includes extensive data exchange features(e.g. MATLAB) for more advanced student projects and reports.
For further details on the software performance, please consult the separate
data sheet on the DynamicStudio Software.

Figure 1.

Figure 2.

Figure 1. Particle motion from vortex ring with overlaid instantaneous PIV vector and scalardata. Vortex core identification based on 2nd invariant Q-values.
Figure 2. Stereo PIV result of a jet flow, the red colors indicate flow towards the spectator,
blue colors represent flow away from the spectator.

Camera and lens
The FlowSense USB 2M-165 camera offers the ideal solution when it comesto performance and ease of use. With its USB interface, the camera can beused with a USB 3.0 PC or laptop without the need for frame grabbers orother hardware. At 1920 x 1200 pixels, the CMOS sensor is capable of 165
frames per second and higher frame rates with reduced region of interest. For
both the EduPIV and the EduStereoPIV system, a low-distortion 35mm lens isprovided. In case of the 2D2C system, it is an f/2.1, c-mount lens to provide theoptimal magnification and field-of-view for the EduPIV flow loop. In the case ofthe 2D3C system, it is an F-Mount lens to allow for enough tilt angle of sensor
to the lens; additionally, it offers a slightly brighter aperture with f2.0 and alarger image diameter. The camera is mounted to a sliding arm on the flow
loop to move the area of measurement quickly and easily within the tank.
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FlowSense USB 2M-165

LED illumination and sheet optics

To provide safe and reliable illumination, an LED light source is used. The
150W illuminator provides the intensity needed for the short exposure times
used in PIV measurements.
The output of the illuminator is coupled to a multi-mode fiber optic bundle.
On the output end of the fiber bundle, the fibers are arranged in a row
to create a line of light. The line is focused with a rod lens to form a sheetof light. The focal point (or saddle point) of the light sheet can easily be
adjusted by moving the rod lens up and down. The compact line light androd lens are affixed to the same sliding arm as the camera so they move
together to measure in different areas of the tank.

LED fiberoptic guide and sheet optics

Pump, Controller and Nozzle
The pump is simple to operate and mounts in the tank via a magnetic
base. The pump is connected to the 3D-printed nozzle via a rubber bootwhich allows for quick and easy removal or replacement. With this flexible
design, students can design and print their own nozzles or conditioners
to create and measure various flows.
The pump controller allows for quick manual adjustments and can beadapted to external control for more complex experiments. The nozzle
has a 5 cm diameter and provides a flat jet profile.

Stereo System and Upgrade

Pump and controller.

To teach and train the basics of Stereo PIV, the 2D2C system can beupgraded, or an EduStereoPIV System can be ordered directly. With thissystem, it is also possible to measure the third velocity component of theflow within the light sheet plane, which results in 2D3C data. For that,an additional camera, Scheimpflug-mounts, and a calibration target aredelivered in addition to the standard EduPIV system.
With the Scheimpflug-mounts, the depth of field problem is corrected whenlooking at a plane with an angle. As with standard systems, the mounts tilt
the sensor plane instead of the lens. This has multiple advantages since
the field of view remains the same when tilting the sensor with a lensfixed. If the lens was tilted, the field of view would change, so the camera
would have to be moved and aligned again. Furthermore, it is possible
to fine align the sensor position to the pivot point. This is necessary tocompensate optical and manufacturing tolerances. Combined with thebright 35mm f2.0 F-Mount lenses, the optical set-up is ready for anything
including more advanced measurements in or outside this flow-loop. To
accommodate the Scheimpflug mounts and the bigger lenses, the camera
rig for the EduStereoPIV system is also redesigned and uses bigger profiles
compared to the standard EduPIV system. This adds more stiffness andreduces the likelihood of cameras moving out of alignment.
To reference the position of the cameras and the relation between them,
it is necessary to spatially calibrate them. This is done by the Dual-layer,
double-sided target which is part of the system and adds additional value,
offering you a calibration with just a single image of the two cameras. This
process sets the industry standard with its fully automatic point detection
algorithms. With it, the setup can be calibrated down to a reprojection
error of below 0.15 pixel. This already great value can be further refineddown to below 0.05 pixel by applying calibration refinement, which almost
eliminates calibration errors.

Scheimpflug mount for EduStereo PIV
system with camera and 35mm f2.0 lens.

Technical specifications
Component

ModelDetails

SoftwareDynamicStudio
EduPIV software

Base package
2D PIV
Complete Image Processing Library
POD analysis
MATLAB, Octave, CFD Link, and much
moreCamera(s)FlowSense USB 2M-165

160 frames per second
1920 x 1200 pixels
USB 3.0 Interface

LEDEduPIV LED

120 W illumination
110/220V input

Light Sheet

Fiber Light

Fiber-optic line light guideCommon parts

OpticsAdjustable Focus Rod Lens
35˚ divergence angle
7.6 cm sheet width at aperture
4mm minimum sheet thickness

Pump

0.2 – 0.5 l/s
Possibility to set sine and square functions
12 VDC

NozzleJet diameter at exit: 5 cm
Flow range: 2 - 5 cm/s

Flow Loop

Lens

EduPIV
Rig
Lens

EduStereoPIV

Software
Rig
Scheimpflug

80 x 35 x 40 cm
112 liters
35mm Low-Distortion
f/2.1 – f/16 aperture35mm focal length
C-mount
Lockable focus and aperture
Height adjustable camera post
f/2 – f/22 aperture
35mm focal length
Nikon F-mount
Stereo PIV Add-on
Robust rig for 2 cameras
2x Scheimpflug mounts

Solution Sheet SS_0591_v4. Subject to change without notice. Copyright © 2021.
Dantec Dynamics. All Rights Reserved. www.dantecdynamics.com