NASA Contractor Report 181841 

AN EXPERIMENTAL INVESTIGATION OF THE 

GROUND VORTEX CREATED BY A MOVING JET 

V.R.Stewart 

Aerodynamic Consultant 

Columbus, Ohio 

July 1989 

... [HASA-CR-I81841) U89-268 15 . A19 EXPBRIlEBTAL 

XlWESTIGAPIOI OF THE GRUJHD VORXBX CREATED 

BY- A 8OVIIG JET (Steuart (V. A,&) 124 p 

CSCL 011 Unclas. 

G3/02 0224Q15 

Prepared for 

NASA Langley Research Center 

under L-29341C 

NASA 
SUMMARY 

The impingement of a vertical jet on the ground creates a 

ground vortex which can cause significant effects on a STOL 

airplane. The ground vortex can have large effects on the 

aerodynamics of the airplane and can result in significant inlet 

distortions in temperature and in flow quality. An experimental 

investigation of the ground vortex has been made in NASA’s 

Langley Vortex Research Facility (VRF) with a moving jet over a 

stationary ground board. Data showing the ground pressures 

resulting from the ground vortex created by the jet moving over a 

fixed ground board at various speeds have been gathered. These 

ground board pressures have been analyzed and the results are 

compared to several existing studies with fixed jets over fixed 

ground boards and to previous tests of a jet moving over the 

ground. 

The results of this comparison show that the penetration of 

the vortex created by the moving jet is diminished when compared 

to that created by a stationary jet. This reduction is shown to 

be approximately a 30% reduction in the centerline penetration 

into the opposing air stream and a reduction in the lateral 

penetration of approximately 50%. These significant reductions 

are believed to be the result of the elimination of the ground 

boundary layer inherent in the fixed jet and ground board of the 

majority of the existing data. 

Just how much the reduction in the vortex size will affect 

the aerodynamic characteristics can not be determined from the 

current data base. The data give some indication that even 

i 
though the vortex penetration is seen to be reduced, the vortex 

appears to be stronger. This indicated may result in a somewhat 

delayed onset of the forces associated with the ground vortex but 

the force change due to the vortex may be more severe. 

Additional data must be obtained with a moving model test to 

provide model forces in addition to the ground vortex position 

and strength. 

ii 
TABLE OF CONTENTS 

SECTION PAGE 

SUMMARY....................................o..g... .... i 

TABLE OF CONTENTS.... ................................. iii 

LIST OF FIGURES ....................................... V 

LIST OF TABLES..................................... ... vii 

SYMBOLS................................................ viii 

INTRODUCTION.......................................... 1 

REVIEW OF EXISTING DATA 4 

Centerline Vortex Penetration 4 

Lateral Penetration of the Ground Vortex 8 

GROUND VORTEX OF MOVING JET 10 

TEST PROCEDURES................................. 10 

Test Facility 10 

Instrumentation 11 

Model.......................... .................. 11 

Test Program ..................................... 12 

DATA ANALYSIS ........................................ 13 

Pressure Distribution. ........................... 14 

Forward Extent................................... 17 

Lateral Shape 18 

COMPARISON WITH PREVIOUS DATA......................... 19 

NOZZLE SURVEYS ....................................... 20 

DATA BASE REQUIREMENTS............ 23 

CONCLUSIONS. 23 

REFERENCES ............................................ 24 

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...... 

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ii i 
APPEND1 X 

A 

B 

C 

TABLE OF CONTENTS (CONT.) 

TITLE 

BASIC DATA FOR THE 1.0 INCH JET 

NOZZLE ............................... BASIC DATA FOR THE 0.6 INCH 

NOZZLE CONFIGURATION ................. NOZZLE SURVEY DATA ................... 

PAGE 

A1 

B1 

c1 

iv 
LIST OF FIGURES 

FIGURE 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

TITLE PAGE 

Formation of the Ground Vortex ................. 27 

Typical Vortex Ground Pressure Distribution ..... 27 

Variation of Jet Free Air Path with velocity 

Ratio ......................................... 28 

Correlation of the Ground Vortex from 

Existing Stationary Model Data ................ 28 

Comparison of Ground Vortex from Existing 

Stationary and Moving Model Data .............. 29 

Lateral Ground Vortex Shape. Ref . 6 ............ 29 

Comparison of Lateral Vortex Shape. Existing 

Data Base. Refs . 1. 5. and 6 .................. 30 

Correlation of Lateral Vortex Shape. Existing 

Data Base. Refs . 1. 5. and 6 .................. 30 

Correlation of Lateral Vortex Shape. Additional 

Stzitionary Model Data ......................... 31 

Facility. Model. and Ground Simulation ......... 32 

Ground Board Pressure Instrumentation. 1" Jet .. 33 

One Inch Jet Nozzle ............................ 33 

Jet Nozzle Installation ........................ 34 

One Inch Jet Nozzle Geometry ................... 34 

Test Conditions for One Inch Nozzle ............ 35 

Ground Board Pressure Instrumentation. . 6" Jet . 35 

0.6 Inch Jet Nozzle ............................ 36 

Tine History of Ground Board Pressures ......... 36 

Ground Pressure Distribution. 1.0" Jet. 

Ve=0.042 ...................................... 37 

Ground Pressure Distribution. 1.0" Jet. 

Ve=0.052 ...................................... 39 

Ground Pressure Distribution. 1.0" Jet. 

Ve=0.090 ...................................... 41 
LIST OF FIGURES (CONT.) 

FIGURE 

22 

23 

TITLE PAGE 

Ground Pressure Distribution, 0.6" Jet ......... 42 

Ground Pressure Field, Position C, 

Run 22, Ve=0.042 .............................. 43 

24 

25 

Ground Pressure Field, Position C, Ve=0.90 ..... 43 

Ground Vortex Forward Penetration, NASA 

Moving Model .................................. 44 

26 Ground Vortex Forward Penetration, 

Correlation of Stationary and Moving Model .... 44 

27 

28 

29 

30 

Ground Vortex Lateral Extent, Ve=0.042 ......... 45 

Ground Vortex Lateral Extent, Ve=0.052 ......... 45 

Ground Vortex Lateral Extent, Vc=O.O90 ......... 46 

Lateral Shape of the Ground Vortex, 

Comparison of Stationary and Moving Models .... 46 

31 Correlation of Lateral Vortex Shape for 

Stationary and Moving Jets, k=1.03, .......... 47 

32 Correlation of Lateral Vortex Shape for 

Stationary, k=1.03, and Moving Jets, k=0.50, .. 47 

33 Lateral Penetration of the Ground Vortex 

at x/d = 0.0 ..................................... 48 

34 Jet Cross Section Pressure Distribution, 

d=1.0", h/d=3.0, Qj = 935 psf .................. 49 

35 Jet Cross Section Pressure Distribution, 

d=0.6", h/d=3.0, Qj = 1054 psf ................ 50 

36 Comparison of Jet Cross Section Pressure 

Distribution h/d=3.0, y/d=O.O ................. 51 

37 

38 

Comparison of Jet Expansion .................... 51 

Cornparison of Average Jet Pressure Coefficient 

Along Jet Centerline .......................... 52 

39 

40 

Comparison of Jet Shaps at y/d=O.O ............ 52 

Effect of Jet Dynamic Pressure on Jet Pressure 

Ratio for the One Inch Jet .................... 53 

vi 
LIST OF FIGURES (CONT.) 

FIGURE TITLE PAGE 

41 Comparison of One Inch Jet Pressure Ratio 

at Various Jet Dynamic Pressures .............. 53 

TABLE 

1 

LIST OF TABLES 

TITLE PAGE 

One Inch Jet Run Schedule and Test Program ..... I3 

vi i 
CP 

d 

F.S. 

h 

NPR 

Qj 

Qo 

T 

Ve 

Vj 

Vm 

Vo or V 

(W/U j 

X 

X' 

Y 

Z 

SYMBOLS 

Pressure Coefficient 

Nozzle Diameter 

Fuselage Station 

Height Above Ground 

Nozzle Pressure Ratio 

Jet Dynamic Pressure 

Free Stream Dynamic Pressure 

Temperature 

Velocity Ratio - Vo/Vj 

Jet Velocity 

Model Velocity 

Free Stream Velocity 

Nozzle Aspect Ratio 

Longitudinal Distance 

Vortex Penetration 

Lateral Distances 

Vertical Distances 

Local Pressure Coefficient 

Jet deflection 

viii 
INTRODUCTION 

The operation of STOL vehicles will be enhanced if the 

engine thrust is utilized to develop lift or stopping force. 

This vectoring of the engine thrust often results in the jet 

impinging on the ground during the terminal phases of the flight. 

This can generate flow fields under the airplane which, in turn, 

can result in large changes in the aerodynamic loads. In 

addition the resulting gas cloud can cause hot gas reingestion 

and possible FOD to the jet engine. 

The primary flow characteristic effecting the aerodynamics 

is called the ground vortex. When a jet strikes the ground 

perpendicularly, a wall jet radiates symmetrically about the 

point of impact. That portion flowing into the oncoming free 

stream is retarded by the free stream and turned back onto itself 

as the ground vortex. The ground vortex penetration is 

controlled by the relative energies in the wall jet and the 

freestream air flow. The wall jet is a thin sheet of air along 

the ground and the retarding of this wall jet will be affected by 

any ground boundary layer present. The presence of a low energy 

ground boundary allows the wall jet to penetrate unrealistically 

far into the free stream. The testing procedures used will 

determine if a ground boundary layer is present under the free 

stream air flow. Testing in a wind tunnel with its moving air 

will create a ground boundary while in actual. flight the airplane 

moves through still air without a ground boundary layer. 

Figure 1 shows the formation of the ground vortex. The 

ground vortex created by an isolated jet is a horseshoe shaped 

1 
flow field about the jet. The vortex, at least in the region to 

the side of the jet, is not a true vortex in that the flow is 

simply redirected aft and then continues along and parallel to 

the free stream. In the region directly upstream of t.he jet the 

flow within the vortex is most likely split to the sides of the 

jet and flows aft around the high energy jet path. These 

characteristics will hold for the concentrated jets discussed in 

this study, but, in the case of the distributed jets such as jet 

flaps and large aspect ratio nozzles, the vortex flow may be 

trapped ahead of the jet and may roll into a very strong vortex. 

The vortex from the jet flap will be entrained by the nozzle jet 

and will appear as a more classic vortex. The present study is 

limited to the concentrated circular jet configurations 

exhausting at ninety degrees, perpendicular, to the ground board. 

Figure 2 presents a definition of terms for the vortex and 

the ground board pressures along the jet centerline. In the 

profile view the jet will be bent aft somewhat by the free stream 

velocity and will impinge on the ground at a point downstream of 

the nozzle centerline. This jet bending will be of concern only 

because of the various methods of data taking in the moving model 

tests and will be discussed later as appropriate. The impinging 

jet creates a large positive ground board pressure region as seen 

in Figure 2. The positive pressure decreases as the distance 

from the nozzle centerline increases and returns to ambient 

downstream of the jet. The data from the moving model tests to 

be discussed later indicate that the downstream centerline 

pressures become negative along the jet centerline. The earlier 

2 
data did not show this characteristic. Upstream of the jet the 

ground board pressures become negative in the region of the 

vortex, and, as the forward velocity of the wall jet slows the 

ground pressures slowly return to ambient. In fact, the data 

show a slightly positive pressure ahead of the vortex. For 

vortex definition, the point at which the negative pressures 

under the vortex return to ambient is picked as the most forward 

travel of the ground vortex. This definition appears to agree 

well with that extent determined from the flow visualization used 

for some of the data. 

The moving model data taken during this study does not 

provide correlation of model position to ground board pressures. 

The ground vortex positioning is therefore measured from the 

point of maximum positive pressure. This maximum positive 

pressure is slightly aft of the nozzle centerline as the nozzle 

passes over the pressure recorder. Figure 3 shows the bending of 

the jet due to the free stream air flow. The data from Reference 

1 show that at a height of three nozzle diameters above the 

ground the bending of the jet is relatively insignificant. At a 

velocity ratio of 0.10 the bending is approximately 0.125 jet 

diameters along the centerline. The forward penetration for this 

condition is approximately 7.5 jet diameters, also from Reference 

1. The effect of the bending of the jet at a height above the 

ground board of 3 diameters would result in an error of less than 

2% of the indicated vortex penetration at the highest velocity 

ratio tested (0.17) and less at lower velocities. These possible 

errors are well within the data accuracy of the system and can be 

3 
dismissed. 

The existing data base consists primarily of stationary jets 

over stationary ground boards. One early study by Abbott, 

Reference 2, provided an interesting insight into the possible 

effects of a moving jet. Also, a previous study of a moving jet 

over the ground in the NASA Vortex Research Facility is presented 

in this review. These data are reviewed in the following 

sect ion. 

REVIEW OF EXISTING DATA 

There have been several previous experimental. studies of the 

ground vortex due to deflected jets. The majority of these 

studies have used a fixed jet exiting over a stationary ground 

board in a cross flow. The ground in this case has a boundary 

layer built up due to the moving free stream. This boundary 

layer has less energy than the free stream and allows the ground 

vortex to penetrate farther up stream. The results of the 

previous studies are summarized in the following sections of this 

report. 

Centerline Vortex Penetration: Schwanties,Reference 3, is 

an experimental investigation of the vortex centerline 

penetration into the oncoming free stream air. In this study, 

Schwanties was mainly concerned with the reingestion effects of 

the ground jet and the effect of the flow variables on the 

reingestion. 

important characteristics of the ground vortex and the effect of 

One experiment is described which yields some 

. 

4 
c 

some basic parameters on that ground vortex. The effect of 

temperature on the vortex was investigated and Schwanties states 

that no consistent effect of jet temperature can be seen. The 

separation point was measured by light pictures of the jet and 

free stream and are defined by Schwanties as being the most 

forward projection of the wall jet developed by the nozzle. This 

definition is different than that used by Weber and Gay and 

presented in Reference 4. Weber and Gay defined separation point 

as the point at which the wall jet began to leave the wall and 

the maximum forward travel was shown to be as much as 20% forward 

of the initial separation point. 

Schwanties also presented ground vortex penetration for one 

temperature (400 degrees centigrade) at several jet velocities 

and at different forward speeds also variations of nozzle 

pressure ratio were presented. This is the only known data which 

has systematically varied jet pressure ratio. The pressure ratio 

does not appear to have a significant effect on the vortex 

penetration. These data indicate that the dynamic pressure ratio 

is a reliable correlating parameter. The data from Reference 3 

are compared to the vortex penetration with other stationary 

model data in Figure 4. 

Stewart and Kuhn, conducted a study of the ground vortex 

with a generic configuration, Reference 1. A jet model was 

tested in several fixed positions over a fixed ground board. The 

study included several nozzle shapes and configurations with 

single and multiple nozzle arrangements. The single circular 

nozzle projected 90 degrees to the ground is used in this 

5 
comparison. 

In Reference 1, the jet was tested at a variety of heights 

ranging from 25 diameters to a minimum of one nozzle diameter for 

certain conditions. Velocity ratios of 0.1, 0.2, and 0.3 were 

tested and the vortex penetration was determined as the point at 

which the ground pressure distribution returned to zero as 

discussed in the previous sections. Ground board pressures were 

available for the jet centerline and three lateral positions. 

Although it is beyond the scope of the present comparison 

this data source provided a look at the effect of the vortex on 

the aerodynamic characteristics through the force balance 

installed on the model shell. Some wing position effects are 

available on the wing-fuselage combination. 

Weber and Gay, Reference 4, presented the results of a 

deflected jet in ground effect with an oncoming air stream. 

Vortex shape characteristics were determined by side view 

photographs. The initial separation as well as the maximum 

penetration could also be determined from the photographs. The 

photographs show a gas cloud which penetrates about 20% ahead of 

the separation point and rises to a height of approxinately 50% 

of the forward travel. The maximum forward vortex penetration, 

120% of the separation point, is compared to the stationary 

model penetration data base in Figure 4. 

Cimbala, Reference 5, describes a series of tests done by 

Pennsylvania State University. Data consisted of ground board 

6 
. 

pressures and flow visualization of the ground vortnx with a 

smoke screen setup. Center line ground board pressures and 

several lateral rows of pressures were obtained as a function of 

height and velocity ratio. The centerline penetration of the 

ground vortex from the Reference 5 tests appear to agree fairly 

well with other data for stationary nozzle tests as seen in 

Figure 4. It appears that the centerline penetration may be 

slightly reduced over the majority of the data at the lower 

Velocity ratios. This may be due, in part, to a possible side 

wall interference. 

Colin and Olivari, Reference 6, present the results of 

another ground vortex study. Again, the data were obtained the 

jet nozzle exiting 90 degrees to a fixed ground board at varying 

velocities and heights over the ground board. Ground board 

pressure instrumentation as well as flow visualization were used 

to determine the vortex position. The vortex penetration at the 

centerline and the lateral vortex shape were determined. Figure 

4 presents the centerline penetration for several Ve conditions 

and are compared to the stationary model data base. 

The available data showing the vortex penetration created by 

a moving jet indicates a reduced penetration into the freestream. 

Abbott, Reference 2, utilized photographs of the dust cloud 

created when the jet crossed over a chalk line on the ground to 

determine the penetration. Abbott's data are compared to the 

stationary model penetration results in Figure 5. The comparison 

shows that a reduction of approximately 30 percent of the 

penetration is experienced due to the elimination of the ground 

7 
boundary layer. 

A second source of vortex data with a moving jet was briefly 

discussed in Reference 7. The tests were conducted by NASA, also 

in the Vortex Research Facility and were of a 0.6 inch jet moving 

over the ground. These data and model are similar to that of the 

present study and are discussed to a greater extent in a later 

section. The data from the 0.6 inch jet appear to favorably 

agree with Abbott's results. 

Lateral Penetration of the Ground Vortex. To date, the only 

data describing the lateral shape of the ground vortex were given 

in References 1, 5, and 6. These data were all for stationary 

jets. The previous investigations of moving jets, References 2 

and 7, did not provide an insight into the character of the 

lateral vortex characteristics. The earliest known lateral 

vortex data was presented by Colin and Olivari, Reference 6. 

Colin and Olivari utilized an oil visualization technique to 

determine the lateral shape shown in Figure 6 and discussed in 

the referenced study. Colin and Olivari also developed a 

theoretical prediction equation based on the relative energy of 

the forward and lateral wall jets and the oncoming free stream 

jet energy. That equation apparently would predict the lateral 

shaping of the ground vortex for the data base generated by Colin 

and Olivari. The correlating equation wcrt?; 

8 

. 
These equations appear to work well for the data of 

Reference 6, but, do not appear to adequately predict the 

penetration in the plane of symmetry for the data in References 1 

and 5. This is likely to be the result of the various other 

causes such as wall effects possible in Reference 5 or to 

different ground boundary layers created by test facility 

configurations. Figure 7 presents the lateral vortex shape from 

each of the references at approximately the same velocity ratio. 

If a simple expression of the ratio of forward penetration to the 

penetration at y=O is used a better lateral match of the several 

sets of data are shown as can be seen in Figure 8. 

Several other test conditions are available from the data 

discussed in Reference 5 which were not included in the published 

analysis. The data included several heights and velocity ratios. 

It was suspected that the data may have been influenced by the 

tunnel side walls. The lateral vortex shapes of these data are 

presented in Figure 9. The results indicate considerable data 

scatter, but, as can be seen in Figure 9a, the penetration 

appears to fall off at extremes of the lateral extent parameters. 

Figure 9a uses a energy factor of k=1.03, the same as Colin and 

Olivari. Reducing this factor to k=0.75, Figure 9b, and to 

k=0.68 in Figure 9c show that a better correlation with base data 

is realized. Whether this is an energy change or a wall. effect 

can not be determined from the existing data base. The composite 

data from all tests, Figure 8, indicate that the vortex for the 

fixed model could extend as much as 13 nozzle diameters to the 

side for a test condition of Ve=O.lO with no wall interference. 

9 
The tunnel wall for the Penn State tests was only 8 nozzle 

diameters form the jet center line. It is impossible Erom the 

data currently available to determine if the side walls would 

indeed suppress the centerline vortex penetration or if there is 

any affect of the walls on the vortex characteristics. No data 

have been found to determine if there is any effect but, it would 

be expected that the overall effect might be one of simulating a 

higher relative speed. 

GROUND VORTEX OF MOVING JET 

An experimental study of the effects of a moving jet on the 

ground vortex has been completed. This experimental study 

performed in the Vortex Research Facility at NASA Langley 

Research Center has shown that the vortex is affected by the 

reduction of the ground boundary layer characteristic in wind 

tunnel testing. The following sections discuss the experiment. 

The analysis of the results are compared to the vortex created by 

a stationary jet impacting on a fixed ground board. 

TEST PROCEDURES 

Test Facility. The ground effect testing of the moving jet 

was done in the Vortex Research Facility at the NASA Langley 

Research Center. The €acility was modified for ground effect 

studies by installing a 150 foot long ground plane assembly 

approximately in the center of the test section (Figure 10). The 

ground board consisted of two parts, a ramp of 100 feet length at 

a slope of 4 degrees and a 50 foot horizontal section. The model 

to be tested is attached to a moving cart at a fixed vertical 

10 
position in the tunnel. As the cart carrying the model 

accelerates and moves through the test section the model 

approaches the ground board at a simulated sink rate (rate of 

descent) which is dependent upon the velocity as given by the 

equation : 

6 = vo tan 4O. 

After passing over the ramp, the model moves over the 

horizontal section to simulate constant altitude flight (see 

Figure 10. See Reference 8 for a discussion of the test facility 

and test variable definition. 

Instrumentation: The data recorded during this test was 

ground board pressure distribution. The pressures were recorded 

by nine Endevco time sensitive pressure transducers located in 

three rows along the model path. Figure 11 shows the location of 

the pressure transducers. The rows of transducers were located 

at (A) 2.5 inches upstream of the junction of the ramp and the 

horizontal section, (B) 10 inches downstream of the junction, and 

(C) 25 feet downstream of that junction. Row A is on the 

simulated glide slope while rows B and C are on the flat portion 

of the ground board. Continuous strip time histories of the 

transducer output were recorded as the jet approached and passed 

over each row. In addition the model speed and the jet nozzle 

conditions were recorded. These data were used to compute the 

distances along the model path and the exit velocity of the jet. 

Model. The model for this series of tests was a one inch 

11 
diameter nozzle suspended from the support sting of the moving 

cart. Figure 12 shows the model and figure 13 presents the model 

and sting installation. As can be seen the nozzle was mounted to 

the sting and directed toward the ground by a series of bends. 

Figure 14 presents the nozzle geometry. The nozzle is formed by 

inserting a constriction with a 15 degree contraction at the 

exit, The outside nozzle shape was contoured by a 45 degree 

slope to an approximately 0.01 inch thick edge at the exit of the 

one inch jet nozzle. The NASA nozzle was fabricated to duplicate the 

nozzle used in the Reference 1 tests, however, the NASA jet 

nozzle was one inch in diameter while the jet in the reference 

had a diameter of two inches. 

Test Program. The tests for the ground vortex study was a 

series of model passes over the ground board. Table 1 presents 

the conditions of the tests. The data points are shown 

graphically in Figure 15. Model speed and nozzle pressure ratio 

were varied resulting in velocity ratios (Ve=A,/ Qo/Qj) of 0.18, 

0.09, 0.05, and 0.04. All data were recorded for a height over 

the horizontal section of three inches or a height to nozzle 

diameter ratio (h/d) of three. The height of position A (on the 

slope) was actually 3.17 nozzle diameters above the ground board 

while the positions B and C were 3.00 nozzle diameters above the 

ground board. Since previous data has indicated that below h/d 

of approximately 4 the vortex characteristics are relakivoly 

unchanged, the slight differences between the heights at position 

A and that at positions B and C can be ignored. 

Similar data were obtained earlier with a test of a moving 

12 
. 

jet over the same ground board. 

with a 0.6 inch nozzle diameter and a different transducer 

placement. Figure 16 shows the location of the pressure 

transducers for the 0.6 inch jet tests. Only the transducers 

located at positions 9 and 10 produced usable data. 

shows the 0.6 inch nozzle and supply pipe. The nozzle was 

identical to the 1.0 inch nozzle geometry shown in figure 14. 

Data were obtained at a height of three nozzle diameters and at 

velocity ratios of 0.080 to 0.132. 

The earlier data was obtained 

Figure 17 

RUN 

12 

13 

14 

15 

21 

22 

25 

26 

27 

28 

29 

31 

32 

40 

42 

43 

TABLE 1. ONE INCH JET RUN SCHEDULE AND TEST PROSRAY 

Qm Qj Qj /Qm 

2.808 1622.400 577.778 

3.168 1645.500 519.413 

2.837 1477.600 520.869 

3.010 1061.100 352.572 

4.277 2502.100 585.040 

4.406 2521.400 572.213 

7.392 229.600 31.063 

7.356 236.500 32.153 

7.439 230.100 30,931 

7.734 220.000 28.447 

7.849 878.400 111.906 

9.567 316.400 33.073 

9.727 323.800 33.288 

11.818 339.500 28.727 

11.818 1536.801.) 130,038 

11.949 1490.700 124.754 

V j /Vo 

24,037 

22.791 

22.823 

18.777 ' 

24.188 

23.921 

5.573 

5.670 

5.562 

5.334 

10.579 

5.751 

5.770 

5.360 

11.403 

11.169 

Ve 

0.042 

0.044 

0.044 

0.053 

0.041 

0.042 

0.179 

0.176 

0.180 

0.187 

0.095 

0.174 

0.173 

0.187 

0.088 

0.090 

Vm/V j 

Vm 

48.600 

51.650 

48.850 

50.350 

59.950 

60.900 

78.850 

78.650 

79.100 

80.600 

81.250 

89.700 

90.450 

99.700 

99.700 

100.250 

DATA ANALYSIS 

The ground vortex discussed previously in the introduction 

is formed when the jet strikes the ground and flows forward into 

the oncoming airstream. The vortex penetration is controlled by 

the velocity ratio and by the height above the ground. 

parameter utilized in this study to define the vortex penetration 

The 

13 
characteristics is the ground pressure distribution. The 

comparison of several references (1 to 7) show, with relatively 

good agreement, that the vortex boundaries can be determined by 

the negative ground board pressure area. The references us:? 130th 

ground pressure and flow visualization techniques to map the 

ground vortex. The vortex penetration is defined as the point at 

which the negative ground board pressure recovers to ambient. 

Pressure Distribution. The ground board pressures were 

measured by the use of high response pressure transducers located 

on the ground board surface. The jet was passed over the 

transducer at the selected velocity. The transducer responded 

with the pressure change as the jet approached and then moved 

away from the transducer. The pressure response was initially a 

small positive pressure as the vortex front approached then a 

negative pressure as the vortex was over the transducer. The 

negative pressure was followed by the large positive impact 

pressure as the jet passed over the transducer that was followed 

by a negative pressure directly behind the jet. Figure 18 is a 

sample time history of the pressure variations. For purposes of 

analysis,the pressures have been converted to pressure 

coefficient, Cp, and the time has been reduced to nozzle diameter 

by converting the time parameter to distance utilizing the model 

speed. Zero distance is considered to be located at the point of 

maximum positive pressure. This resulted in a small position 

error as discussed above. 

The pressure coefficient results for all data runs for the 

14 
one inch nozzle are presented in Appendix A and the data for 0.6 

inch nozzle are presented in Appendix B. The position of the 

pressure instrumentation rows on the ground board does not appear 

to affect the vortex characteristics. The pressure variation on 

the ground board appears to be approximately the same at all 

positions. The knee, the longitudinal point at which the slope 

ramp and the horizontal section join, does not appear to affect 

the vortex. The height of the model above all three positions is 

nearly the same and any effect of the knee is not apparent at 

position B, ten nozzle diameters downstream of the knee. 

Figure 19, 20 and 21 show the ground board pressure 

distribution of the one inch jet and for the test velocities of 

Ve= 0.42, 0,092, and 0.17 respectively. The pressure traces 

along the center of the jet path show the positive pressure from 

the jet itself to have a larger impact area than expected. The 

jet appears to be approximately 6 nozzle diameters wide at the 

ground board for Ve of 0.09. This spreading is somewhat similar 

to that experienced with fixed nozzle position testing by 

Stewart and Kuhn, Reference 1, Colin and Olivari, Reference 6, 

and others, but is rather greater than seen during a previous 

test with a 0.6 inch moving model tested by NASA (see Figure 22). 

The reason for this difference in the apparent spreading can not 

be isolated from the data. Jet exit profiles takpn of both 

nozzles do not indicate a noticeable difference in jet spreading 

as will be discussed later in this report. The apparent 

different spreading may be a different transducer response 

characteristic caused by a different mounting technique. The 

15 
negative pressure indicated for the transducers located on the 

ramp with the 0.6 inch nozzle appear to be in error and are not 

included in this analysis. 

The time histories of the individual pressure transducers 

allow the ground pressure distribution of the vortex-jet system 

to be determined for the various conditions. Figure 23 and 24 

show the pressure fields for velocity ratios of 0.042 and 0.09 

respectively. Three distinct pressure regions are shown by the 

results. A negative pressure region is seen in the vicinity of 

the vortex. This negative pressure region extends ahead of the 

nozzle and laterally several nozzle diameters. The forward edge 

of the negative pressure field is the forward extent of the 

vortex. The forward edge of the vortex is curved aft as the wall 

jet forward energy decreases as the lateral distance increases. 

At a Ve of 0.042 the negative pressure field of the ground vortex 

extends laterally to approximately 18 nozzle diameters while at 

Ve of 0.09 that distance is reduced to about 10 nozzle diameters. 

The area under the jet experiences a positive pressure field 

due to the impact of the jet on the ground. The positive 

pressure region is shown to be larger than expected in these 

data. In fact, along the centerline and at a velocity ratio of 

0.09 the vortex is masked by the apparent impact area. The 

impact area is larger than shown in Reference 3, but, is about 

the same as shown in Reference 1 and 7. No explanation for the 

differences between this data and that of Reference 3 can be 

isolated from the data. It is possible that the flush mounting 

of the pressure instrumentation for this test allowed the jet 

16 
turbulence to mask the vortex pressures and that the Reference 3 

instrumentation could have been recessed slightly which would 

damped the turbulence effects. 

Immediately behind the jet a negative pressure field is 

encountered. This area of negative pressure is the result of the 

high velocity wall jet and is amplified by the blocking effect of 

the jet post. The freestream air flow is accelerated around the 

jet post as it flows into the area behind the post thereby 

increasing the negative pressure in this area. 

Forward Extent. Figure 25 shows the centerline vortex 

penetration of the one inch jet compared to the 0.6 inch jet and 

that of Abbott's rotating arm data. The forward penetration of 

the ground vortex of the one inch jet is the same as that from 

the earlier test of the 0.6 inch jet, Reference 7. The 

penetration of the ground vortex from each of the nozzles tested 

in the NASA moving model facility agree well with that shown by 

Abbott from the rotating arm rig, Reference 2. Abbott's data 

were obtained at considerably higher values of Vj/Vo than most of 

the data base and also higher than the moving jet data. The 

vortex penetration of the NASA moving model data show a ground 

vortex to be formed at velocity ratios of 0.042 to 0.092, but, no 

vortex can be found at the highest velocity ratio tested, 

Ve=0.17. As can also be seen in Figure 26, the vortex 

penetration of the moving model data show a reduction compared to 

the stationary model data base of approximately 30 percent. 

' 

An extrapolation of the moving model data from the lower 

17 
velocities to Ve-0.17 would would indicate that a vortex at that 

speed would be expected. The penetration of the ground vortex at 

Ve=0.17 would be expected to be about two nozzle diameters. The 

ground board pressure for a sample jet pass over the ground at 

Ve=0.17 is shown in Figure 18, As can be seen, the jet width, 

positive pressure region, is too wide to ascertain the presence 

of a ground vortex in this case. The vortex may well exist in 

the region of the positive pressure indicated by the pressure 

instrumentation, but, in any case would penetrate only a small 

distance ahead of the jet impact region. 

Lateral Shape, The lateral extent of the ground vortex from 

the moving jet tests can be seen in Figure 27, 28, and 29. The 

vortex is shown to extend several nozzle diameters to the side of 

the jet. The data show that the lateral extent of the vortex is 

approximately 1.5 as much as the forward penetration. The 

lateral penetration of the jet vortex is the characteristic which 

is thought to determine the abrupt change in the aerodynamics of 

the airplane in the presence of the ground. The vortex, if 

present under a non lifting surface would be expected to show a 

lift loss equivalent to the negative pressures on the ground 

which would be reflected back onto the surface. In a case in 

which the vortex is under a lifting surface, such as the wing, 

the negative pressures would be felt on the wing also. But, in 

this case the circulation lift is created by the angle of attack 

at the wing leading edge of the wing. This angle of attack can 

be greatly altered by the presence of the ground vortex. With 

the vortex located aft on the wing a positive angle of attack 

18 
will be induced on the wing. As the vortex extent approaches the 

wing leading edge the wing flow will be disrupted and if the 

vortex extends forward of the leading edge, the leading edge may 

be enveloped in a reduced velocity flow field and a significant 

reduction of the circulation lift may result. 

COMPARISON WITH PREVIOUS DATA 

The vortex formed by the moving jet differs from that of a 

stationary jet in both forward penetration and lateral extent and 

shape. The forward penetration is reduced by approximately 30 

percent by the elimination of the ground boundary layer. An even 

more significant effect can be seen in the lateral penetration of 

the vortex. The data from the moving jet show the lateral shape 

of ground vortex to be altered from that occurring under the 

stationary jet. The shape of the vortex to the side of the jet 

appears to be swept aft at a greater angle. Figure 30 shows the 

lateral shape for several vortex conditions of the stationary and 

moving models. These lateral shapes are correlated in Figure 31 

with the parameters discussed previously. The energy factor 

shown in Figure 31 is k=1.03 from Colin and Olivari. The 

stationary jet data base appears to be well represented by this 

computation while a much reduced lateral penetration of the 

moving jet vortex is seen. Figure 32 shows that if k=O.5 is used 

for the moving jet energy ratio a very good agreement can be 

shown for the comparison. The reduction in the energy factor is 

consistent with the expected result of the elimination of the 

ground boundary layer. 

19 
The effect of the reduced relative energy described abovc is 

reflected in a reduction of the expected lateral extent of the 

ground vortex. Figure 33 is a comparison of the lateral extent 

of the vortex formed by the moving jet compared to that formed by 

a stationary jet, The calculation utilizing the 30 percent 

reduction in centerline forward penetration and the indicated 

reduction of 50 percent in the relative energy factor, k, show 

approximately a 50 percent reduction in the lateral extent of the 

ground vortex formed by the moving model. 

NOZZLE SURVEYS 

The ground pressure distribution of the one inch jet is 

somewhat different from that of the 0.6 inch jet. The positive 

pressure region created by the impact of the jet on the ground by 

the one inch jet is approximately twice as large as that from the 

0.6 inch jet. These data are recorded for a height of three 

nozzle diameters above the ground board for each nozzle. Data 

presented by Stewart and Kuhn, Reference 1, and by Colin and 

Olivari, Reference 6 appear to verify the larger impact areas. 

These referenced studies were with a stationary jet over a 

stationary ground board. The 0.6 inch jet positive pressure 

field is compressed compared to this other existing data base, 

but, does appear to be represenative of the jet width at the 

ground height of the current tests. 

The jets from the 1.0 and the 0.6 inch nozzles were surveyed 

at several distances from the jet exit. Surveys were taken by a 

total pressure survey probe at distances of 0.2, 1.0, 3.0, and 

20 
10.0 nozzle diameters from the nozzle exit. The complete data 

for these surveys are presented in Appendix C. The jet shapes at 

the ground height of h/d=3.0 are presented in figures 34 for the 

one inch jet and in Figure 35 for the 0.6 inch jet. Figures 34a 

and 35a present the left one half of the jet and Figures 34b and 

35b present the right portion of the jet. The jets from the two 

nozzles have comparable expansion characteristics at the height 

shown. Figure 36 shows a comparison of the centerline survey at 

this height. The jet shapes are essentially the same with the 

smaller jet showing a slightly greater centerline pressure. 

The jet characteristics are summarized in Figures 37, 38, 

and 39. The comparisons are made for dynamic pressure ratios of 

935 psf for the one inch jet and 1054 for the 0.6 inch jet. 

Figure 37 compares the width of the jets. The data show no 

consistent differences in the jet width at any height. Figure 38 

presents the relative jet pressures along the flow path. The 

average initial pressure ratio of the 0.6 inch jet is slightly 

greater due to a slightly skewed pressure distribution at the 

exit and therefore has a slightly higher velocity along the flow 

path. Figure 39 shows the jet shape in the longitudinal plane 

centerline. The spreading rates are consistent with the smaller 

jet deflected 2 to 3 degrees less than the one inch jet. This 

greater velocity and the slight under deflection of the jet tend 

to be compensating in the cornparison of the ground vortex 

penetration. 

The flow surveys indicate that the pressure distributions 

21 
are relatively unaffected by the jet dynamic pressure, at least 

at the test conditions. Figures 40 and 41 show the effect of the 

jet dynamic pressure on the results of for the one inch nozzle. 

The flows are the same for jet pressures of 265 and 935 psf, but 

at the lower flows, q=85 psf the indicated pressures are less 

than the calibration would suggest. These lower values are 

likely the result of the inaccuracies in the calibration at the 

lower flow rates. The tests were conducted at q>265 so the 

results are not affected by this characteristic. 

The surveys of the exit and downstream pressures of the two 

nozzles show that the jet characteristics are nearly identical at 

all positions surveyed. The flow characteristics do not show an 

explanation for the different impact regions discussed earlier. 

The different impact area seen may be attributed to an 

instrumentation or to an instrumentation installation 

discrepancy. The installation of the transducers for the later 

test of the one inch nozzle covered a larger field with a 

concentration along three lateral rows. The transducers were 

installed flush with the ground board. The 0.6 inch test 

utilized a sparse coverage with instrumentation. The comparison 

of the one inch results with that of References 1 and 6 indicates 

that the one inch jet shapes are in better agreement. The 

comparisons of the vortex penetration of the two jets indicate 

that the impact area differences are the result of the data 

acquisition or recording parameters and do not affect the vortex 

penetration. Until investigated utilizing a common data 

recording installation, these differences in the impact area will 

22 
remain unexplained. 

DATA BASE REQUIREMENTS 

The development of the aerodynamic characteristics of STOL 

aircraft which utilize power to augment the lift or to brake the 

configuration will require additional in ground effect data. The 

available data have shown that a significant change in the 

aerodynamic characteristics can be caused by the ground vortex. 

The positioning of the vortex relative to the lifting surfaces is 

known to be a critical variable. The effect of the ground 

boundary layer has been shown by this data to be the critical in 

controlling both the forward and lateral penetration of the 

ground vortex. There is no available data to determine the 

aerodynamic increments on a moving model. 

A data base generated using a moving model and containing 

proper ground pressure measurements to determine the vortex 

penetration is required. Several test procedures can be utilized 

to provide this data. The most straight forward would be a test 

procedure utilizing the setup in the Vortex Research Facility 

for the vortex penetration study and incorporating a generic 

model to provide the aerodynamic characteristic measurements. 

This procedure provides a reasonably adequate measur2ment of the 

vortex by the ground pressure surveys and the aerodynamic 

characteristics by the balance instrumentation. Significant 

configuration variables are wing position and sweep, longitudinal 

control surface location, and jet nozzle shape and deflection. 

It is recommended that the Vortex Research Facility be used 

23 
to provide the extension of the ground effect data base. 

CONCLUSIONS 

The jet moving over the ground results in a reduced vortex 

from that created by a stationary jet. Most of the previously 

existing data base of jets impinging on the ground was dealt with 

as a stationary jet problem. The known possible source of error 

was the ground boundary layer created by the tunnel air moving 

over the ground. It had been expected that with the concentrated 

jets of consideration this would be a minimum problem. This 

study utilizing a moving jet over a fixed ground board shows that 

significant difference can be expected. 

The forward penetration is shown to be reduced by as much as 

30 percent and the lateral extent can be reduced by approximately 

50 percent. The overall effect of these large reductions on 

configuration aerodynamics can not be predicted without specific 

planform testing. 

It is concluded that additional moving model data with 

airplane configurations and aerodynamic force instrumentation are 

required provide data to determine the aerodynamic responses of 

the configurations. 

REFERENCES 

1. Stewart, V. R. and Kuhn, R. E.: "A Method for Estimating the 

Propulsion-Induced Aerodynamic Characteristics of STOL Aircraft 

in Ground Effect", NADC 80226-60 Aug. 1983 

24 
2. Abbott, W. A.: "Studies of Flow Fields Created by Vertical 

and Inclined Jets Moving over a Horizontal Surface", ACR Cp No. 

911, 1967. 

3. Schwanties, E.: "The Recirculation Flow Field of a VTOL 

Lifting Engine", NASA TT F-14912 June 1973. 

4 . Weber, H. A. and Gay, A.: "VTOL Reingestiom Model Testing of 

Fountain Control and Wind Effects", AIM Paper 75-1217, AIAA/SAE 

Eleventh Propulsion Conference, Sept. 29 to Oct. 1. 1975. 

5. Cimbala, J. M., Stinebring, D. R., Treaster, A. L., and 

Billet, M. L.: "Experimental Investigation of a Jet Impinging on 

a Ground Plane in the Presence of a Cross Flow", NADC Report 

87019-60, March 1987. 

6. Colin, P. E. and Olivari, D.: "The Impingement of Circular 

Jet Normal to a Flat Surface with and without Cross Flow", von 

Karman Institute for Fluid Dynamics, Rhode-St., Genese, Belgium, 

Report AD688953, Jan. 1969. 

7. Stewart, V. R.: "The Characteristics of the Ground Vortex 

and its Effect on the Aerodynamics of the STOL Confi-guration", 

NASA CP 10008, 1987 Ground Vortex Workshop, pp. 1-38, April 1987. 

8. Kemmerly, G. T. and Paulson, J. W. Jr.: "Exploratory 

Evaluation of a Moving Model Technique For Measurement of Dynamic 

Ground Effects", AIAA Paper 87-1924, June, 1987. 

25 
---..4* 

//I// I/ ///,')I,, 

1: 

L.-- 

CP 

8 

-4 

EST IRATE D 

FRfE AIR PATH 

OF MASS FLOW 

Figure 2. Typical Vortex Ground Pressure Distribution 

27 

PRECEDLNG PAGE BiAFdK NOT FilMED 
c 

t, 

t 

4 

n 

m 

7 

4 

0 

-0.1 

-0,2 

-0.3 

-0.4 

-0.5 I I I I I I I 

0 0.1 0.2 

Ve 

0.3 0.4 

Figure 3. Variation of Jet Free Air Path with velocity 

Ratio 

50 

40 

30 

20 

10 

0 

0 20 40 80 100 120 

Figure 4. Correlation of the Ground Vortex from Existing 

Stationary Model Data 

28 
0 0’15 

0 20 40 60 180 100 120 

1 /Ve 

Figure 5. Comparison of Ground Vortex’ from Existing Stationary 

and Moving Model Data 

3 

L I 

i 

1 l-i A EXPERMENTAL 

i 

-’ i 

--I .5 i I 

I I 

n 2 17 t; 1 

I -- 

14 -1 -0 6 -0 2 

.1 C’AHAtdLTEF.’ 

Figure 6. Lateral Ground Vortex Shape, Ref. 6 

29 
7 !-- 1 

2 

1.9 - 

1,8 - 

1B7 - 

1.6 - 

1.5 - 

1.4 - 

1.3 - 

1-2 - 

1.1 - 

0.9 - 

0.8 - 

0.7 - 

0.6 - 

14L 

PENN ST V.e=O. 2 

NADC Ve=O-. 2 

+ COLIN 'Ve=O.19 

PENN ST Vs=O.2 

+ COLIN Ve=O. 19 

X NADC Ve=O. 2 

P NADC Ve=O. 1 

- 

. . 

t 

y/d - DISTANCE FROM CENTER LINE 

+ 

IIIIII I1 Ill1 II Ill1 

0,8 1 1.2 1.4 1.6 1.8 2 0 0.2 0.4 0-6 

v/d 

k(Vj/ve).g 

Figure 8. Correlation of Lateral Vortex Shape, Existing Data 

Base, Refs. 1, 5, and 6 

30 
.+ Stationary Model Average 

Penn. State Ve-0.10 

0 0.2 0.4 0.6 0.8 1 1.2 1,4 1,6 1.8 2 

- via 

k(V jive) -9 

a. k=l .03 

2 

1.9 

1.8 + Stationary Model Average 

1,7 penn. S t a t e V e = 0 . 1 0 

1.6 

1.5 

1.4 

1,3 

s- 1 :I. * .l'l 0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

A 1,2 

1 0.8 ' .2 1.4 1.6 1.8 2 0 0.2 0.4 0.6 !?Id 

k(V j/Ve 1-9 

b. Variable k, ks=1.03, kp=.68 

Figure 9. Correlation of Lateral Vortex Shape, Additional 

Stationary Model Data 

31 
-1 830'- 

Model 

board 

14' x 17' 

Ground test section 

B-B 

"00 Cart 

-b-nb 

4' ramp 

A-A 

Support strut, sting, 

high pressure airline 

and instrumentation 7 

Figure 10. Facility, Model, and Ground Simulation 

32 
TAP II . 

2 

4 

5 

6 

7. 

9 

10 

11 

12 

POSITION X Y 

-2.5 INCHES 0 

-2.5 inches 5.5 INCJIES 

10.0 INCHES n 

10.0 INCHES 1.5" INCHES 

10.0 INCHES 7.5 INCHES 

25.0 FEET 

25.0 FEET 3.0 INCHES 

25.0 FEET 7.0 INCHES 

25.0 FEET 15.0 INCHES 

0 

I rd I 

Figure 11. Ground Board Pressure Instrumentation, 1" Jet 

Figure 12. One Inch Jet Nozzle 

33 

ORIGINAL PAGE 

SLACK AND WHITE PHOTOGRAPH 
IA . I 

3.0 inches 

Figure 13. Jet Nozzle Installation 

0. 

0. 

0*0677 

i 

Figure 14. One Inch Jet Nozzle Geometry 

34 
Vm 

100 -I LVe = 0.18 

..- , 

I 

1 .? 1 ..t 1.6 i .n -! .? ? :'4 1 

- ,- PnIPo 

Figure 15. Test Conditions for One inch Nozzle 

7 

8 

9 

10 

X Y 

-10'5 ft. 0 not presented 

-0.5 ft 0 not presented 

25.0 ft. 0 

25.0 ft 2 inches 

Figure 16. Ground Board Pressure Instrumentation, .6" Jet 

35 
Figure 17. 0.6 Inch Jet Nozzle 

CP 

0,4 

0.3 

0.2 

0,l 

0 

-0.1 

-0.2 

RUN 22 TRACE 10 

I 

I I I 1 1 1 1 1 1 1 1 1 1 1 1 I 

0 0.02 0.04 0.06 0,08 0.1 0.1 2 0.1 4 

TIME - SECONDS 

Figure 18. Time History of Ground Board Pressures 

36 
CP 

trace 2 

10 

0 

-10 

-1 6 -8 0 8 

x'/d 

trace 5 

-1 6 -8 0 

xl/d 

8 

CP 

CP 

trace 4 

10 

0 

-10 ..... 

-1 6 -8 0 8 

x'/d 

10 

0 

-10 

trace 6 

-16 -0 0 

xl/d 

8 

Figure 19. Ground Pressure Distribution, 1.0" Jet, Ve=0.042 

37 
CP 

CP 

10 

0 

10 

trace 9 

I!! !*!!!!!' I I 111 

-. ._ 

-16 -a 0 

x'/d 

trace 11 -- 

8 

1u 

0 

-1 0 

.. 

-16 -8 

CP 

CP 

0 a 

trace 10 

10 

0 

-10 ..... .,. -16 -8 0 

x'/d 

8 

trace 12 

10 

0 

-10 

-16 -8 0 a 

x '/d x /a 

Figure 19 (cont.). Ground Pressure Distribution, 1.0" Jet, 

Ve=O . 0 4 2 
CP 

trace 2 

10 

0 

-10 

-16 -8 0 8 

xl/d 

trace 5 

10 

CP 0 

-1 0 

-16 -8 0 8 

X1/d 

trace 7 

10 

CP 0 

-10 

-16 -8 0 8 

xl/d 

CP 

trace 4 

10 

0 

-10 

-1 6 -8 0 8 

xl/d 

trace 6 

10 

CP 0 

-10 

-16 -8 0 8 

x ' /d 

Figure 20. Ground Pressure Distribution, 1.0" Jet, Ve=0:090 

39 
trace 10 trace 9 

10 10 

CP 0 CP 0 

-10 -10 

-8 0 8 -16 -a 0 8 

x'/d- .Jii x I /d 

-16 

10 

CP 0 

-10 

trace 11 

-1 G -13 0 

x I /a 

8 -16 

.... 

-8 0 8 

x'/d 

Figure 20 (Cont.). Ground Pressure Distribution, 1.0" Jet, 

Ve=0.090 

40 
trace! 4 

10 

CP 0 

-10 

-1 6 -8 0 a 

x /d 

trace 5 trace 6 I 

-1 

-0 

0 

0 

10 

0 CP 

C P 

-16 -8 0 

x'/d 

8 IV 

-16 -a 0 8 

x I ,'d 

trace 9 

trace: 10 10 

CP 0 

-10 

10 

0 

-0 

CP 

-I 

-16 -8 0 -a 0 

x ' /d 

a 8 -1 6 

x'/d 

Figure 21. Ground Pressure Distribution, 1.0" 

41 

Jet, Ve=0.170 
trace 9 

CP 

-16 -8 0 8 

x'/d 

CP 

trace 10 10 

0 

-10' 

-16 -8 0 8 

x'/d 

b. Run 73, Ve=0.132 

trace 9 

10 

CP 0 

-10 

-16 -8 0 

xl/d 

8 

a. Run 74, Ve=0.093 

-16 -8 0 

xl/d 

8 

Figure 22. Ground Pressure Distribution, 0.6" Jet 

42 
20 - 

16 - 

/ 

0 

VOR I' 

,/ 

Yfd 

1 

1% 

rEX I 

I 

nep,ative pressures 

\ 

/ I 

/ 

/ VOR EX 

nep, tive pressures k / 

/ 

/ 

12 - 

/ 

/ 

8- / I 

x'ld 

Figure 23. Ground Pressure Field, Poeition C, Run 22, Ve=0.042 

12 - 

Yld 

8- 

/- -. /--- \ 

/ I 

Figure 24. Ground Pressure Field, Position C, Ve=0.90 

43 
0 20 

llVe 

40 

Figure 25. Ground Vortex Forward Penetration, NASA, Moving Model 

50 

40 

30 

I 10 

I 0 

0 20 40 60 80 100 120 

1IVe 

Figure 26. Ground Vortex Forward Penetration, Correlation of 

Station and Moving Model 

44 
0 10 12 14 2 4 6 0 

y/d - DISTANCE FROEI CENTER LINE 

a 

-. 6- 

- 

- 

x 

4- 

2- 

- 

0 

Figure 27. Ground Vortex Lateral Extent, Ve=0.042 

\ 

I I 1 I 1 I I I I .- I I I I I 

12 . 

l4 1 a 

2 

0 POSITIOY A 

+ B 

C <> 

\. 

J 

\ 

0 I I 1 I 1 I I I I .- I I I I I 

Figure 28. Ground Vortex Lateral Extent, Ve=0.052 

45 
::j 8 

14 - 

13 - 

12 - 

1- - I - __ , _. ,-... r--r-- 

10 12 1 14 

yta - DISTANCE FROM CENTER LINE 

--- 

PENN ST. Ve=0.2 

+ COLIN Ve=O. 19 

0; I I I 1 I I 1'1 I I I I I I 

0 4 6 - i I? 1: f4 

y/d - DISTANCE FROM CENTER LINE 

Figure 30. Lateral Shape of the Ground Vortex, 

Comparison of Stationary and Moving Models 

46 
1.9 - 

1.8 - 

c,7 - 

1s - 

1.5 - 

0 31: h 

x\ 

X 

- 

PENN ST. Vez0.2 + COLIN Ve=O. 19 4 NASA Ve=O. 09 

A NASA 

x NADC 

v NADC 

1.9 - 

1,8 - 

::; 

0,5 

1 

0,9 

0,8 

0.7 

0.6 

0,5 

0.4 4 . 

::; 

0.1 

0 

A 

Ve-0,042 

Ve=O. 2 

Ve-0.1 

+ 

0 0.2 004 0.6 0.8 1 1.2 1,4 1.6 1.8 2 

y/d 

k(Vj/Ve).9 

Figure 31. Correlation of Lateral Vortex Shape for Stationary and 

Moving Jets, k=1.03 

1.3 

1.2 

1.1 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0,3 

0.2 

PENN ST. Ve=O. 2 

+ COLIN Ve=O. 19 

4 NASA Ve=O. 09 h NASA Ve=O. 042 

x NADC Ve=O. 2 

v NADG Ve=O. 1 

I I I I II 11 II I1 I1 II II 

0.6 0.8 1 1.2 1.4 1.6 1.8 2 Q 0.2 0.4 

y/a 

k(Vj/Ve) s9 

Figure 32. Correlation of Lateral Vortex Shape for 

Stationary, k=1.03, and Moving Jets, k=0.50, 

47 
30 

28 - 

26 - 

24 - 

22 - 

20 - 

/ 

8 

/ 

I 1 I I I 1 I I I I I I 1 

8 12 16 20 24 28 0 4 

1 DO 

Figure 33. Lateral Penetration of the Ground Vortex 

at x/d = 0.0 

48 
1.5 I 

1.4 - 

1.3 - 

1.2 - 

1.1 - 

1 -' 

0.9 - 

0.8 - 

0.7 - 

0.6 - 

0.5 - 

0.4 - 

0.3 - 

0.2 - 

0.1 - 

0 -0.40 

A -0.60 

r: -0.80 

0 -1 .oo 

I - o/ I 

-1 1 -3 

0 y/d=O 

+ 0.20 

0 0.40 

A 0.00 

0.8r) 

V 1.60 

x. 

Figure 34. Jet Cross Section Pressure Distribution, d=1.0", 

h/d=3.0, Qj = 935 psf 

49 
1.2 

1.1 

0 y/d=O 

f -0.33 

0 -0.67 

b -1.00 

x -1.33 

V -1,. 67 

5 1.5 2.5 

\ 0.5 

1 

0.9 

0,B 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

1.5 

1.4 

1.3 

1.2 

1.1 

1 

0.9 

0.8 

0.7 

0,6 

0.5 

0.4 

0,3 

0.2 

0,l 

0 

-2.5 -1.5 -0.5 

X/d 

i 

0 y/d=O 

-2.5 -1.5 -0.5 0.5 

x/d 

1.5 2.5 

Figure 35. Jet Cross Section Pressure Distribution, d=0.6", ~ h/d=3.0, Qj = 1054 psf 

I 

50 
1.5 I 

1.3*4 j 

1 

0.9 

008 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

0 0.6" Nozzle 

+ 1.0" Nozzle 

-2.5 -1.5 -0.5 0.5 1.5 2.5 

x /d 

Figure 36. Comparison of Jet Cross Section Pressure Distribution 

h/d=3.0, y/d=O.O 

Y 

u 

0 0.6" Nozzle 

+ 1.0" Nozzle 

2 4 6 8 10 12 0 

h/d 

Figure 37. Comparison of Jet Expansion 

51 
3 

1.9 - 

1,8 - 

1.7 - 

1.6 - 

1.5 - 

1.4 - 

1.3 - 

1.2 

1,l 

1 

0.9 

0.8 

0.7 

0,6 

0.5 

0.4 

0.3 

0 0.6" Nozzle + 1.0" Nozzle 

I 

0.2 - 

0.1 - 

0 

4' 

I I 1 

i 

1 

0 

-1 

- 'f 

-3 

+ 

. -_ --... . 

I I 1 I I I I I I I I 

a 10 12 0 2 4 

h/d 

Figure 39. Comparison of Jet Shapes at y/d=O.O 

52 
1,5 

1.4 

1.2 

1.9 - 

1.8 -' 

h/a=0.2 

* 1.0 

0 3.0 

A 10.0 

0.1 - 

0 

E 

0.9 

0.8 

H 

I 

0.7 

0.5 

4 b 

.2 

0.2 

0.1 

01 I I I 1 1 I I I 1 

0 0.2 0.4 0.6 1 

(Thousands) 

JET Q 

0.8 

Figure 40. Effect of Jet Dynamic Pressure on Jet Pressure Ratio 

for the One Inch Jet 

1.4 

1.3 

1.2 

53 
APPENDIX A 

BASIC DATA FOR THE 1.0 INCH JET NOZZLE 
APPENDIX A 

LIST OF FIGURES 

FIGURE TITLE 

A1 Ground Board Pressure Distribution, 

Run 12, Ve=0.042 

A2 Ground Board Pressure Distribution, 

Run 13, Ve=0.043 

A3 Ground Board Pressure Distribution, 

Run 14, Ve=0.043 

A4 Ground Board Pressure Distribution, 

Run 15, Ve=0.053 

A5 Ground Board Pressure Distribution, 

Run 21, Ve=0.041 

A6 Ground Board Pressure Distribution, 

Run 22, Ve=0.041 

A7 Ground Board Pressure Distribution, 

Run 25, Ve=0.168 

A8 Ground Board Pressure Distribution, 

Run 26, Ve=0,166 

A9 Ground Board Pressure Distribution, 

Run 27, Ve=0.169 

A1 0 Ground Board Pressure Distribution, 

Run 28, Ve=0.187 

A1 1 Ground Board Pressure Distribution, 

Run 29, Ve=0.095 

A1 2 Ground Board Pressure Distribution, 

Run 31, Ve=0.174 

A1 3 Ground Board Pressure Distribution, 

Run 32, Ve=0.173 

A1 4 Ground Board Pressure Distribution, 

Run 40, Ve=0.187 

A1 5 Ground Board Pressure Distribution, 

Run 42 Ve=0.088 

PAGE 

A4 

A6 

A8 

RLO 

A1 2 

A1 4 

A16 

A1 7 

A18 

A1 9 

A20 

A2 2 

A23 

A24 

A2 5 

A1 
LIST OF FIGURES (CONT.) 

FIGURE TITLE 

A1 6 Ground Board Pressure Distribution, 

Run 43, Ve=0.090 

LIST OF TABLES 

TABLE TITLE 

A1 RUN SCHEDULE AND TEST CONDITIONS 

A2 INSTRUMENTATION LOCATION 

PAGE 

A27 

PAGE 

A3 

A3 

,A2 
12 0.0195 2.808 

13 0.022 3.168 

14 0.0197 2.8368 

15 0.0209 3.0096 

21 0.0297 4.2768 

22 0.0306 4.4064 

25 0.05133 7.39152 

26 0.Q5108 7.35552 

27 0.05166 7.43904 

28 0.053706 7.733664 

29 0.05451 7.84944 

31 0.066436 9.566784 

32 0.06755 9.7272 

40 0.08207 11.81808 

42 0.08207 11.81808 

43 0.08298 11.94912 

TABLE Al. RUN SCHEDULE AND TEST CONDITIONS 

Qm Qj Qf/Qm Vj/V v/vj RUN Qm 

1622.4 

1715. S 

1477.6 

1061.1 

2502.1 

2601.1 

259.3 

267.2 

259.8 

220 

870.4 

316.4 

323.8 

339.5 

1336.8 

1490.7 

577.7777 

541. SO88 

520.8685 

352.5717 

585.0402 

590.3004 

35.08074 

36.32645 

34.92386 

28.44705 

11 1.9060 

33.07276 

33.28809 

28.72717 

130.0380 

124.7539 

24 03700 

23.27034 

22.82254 

18.77689 

24.18760 

24.29609 

5.922899 

6.0271 43 

5.909641 

5.333578 

10.57856 

5.750892 

5.769583 

5.359773 

11.40342 

11.16933 

' 0.041602 

0.042973 

0.043816 

0.053256 

0.04 1343 

0.041 1'58 

0.168836 

0.165916 

0.169215 

0.187491 

0.094530 

0.173886 

0.173522 

0.186575 

0.087692 

0.089530 

TAP 

2 

4 

5 

6 

7 

9 

10 

11 

12 

TABLE A2. INSTRUMENTATION LOCATION 

POSITION 

C 

C 

C 

C 

X 

-2.5 INCHES 

-2.5 inches 

10.0 INCHES 

10.0 INCHES 

10.0 INCHES 

25.0 FEET 

25.0 FEET 

25.0 FEET 

25.0 FEET 

Y 

0 

0 

5.5 INCHES 

1.5 INCHES 

7.5 INCHES 

3.0 INCHES 

7.0 INCHES 

15.0 INCHES 

0 

A3 
CP 

CP 

CP 

10 

0 

-10 

-1 6 -8 0 8 

x'/d 

trace 4 

10 

CP 0 

-10 

-1 6 -8 0 8 

x'/d 

trace 5 trace 6 

10 

0 

-1 6 -8 0 

x'/d 

8 

CP 

10 

0 

-in -- -16 -8 0 

xl/d 

a 

Figure ~l . Ground Board Pressure Distribution, Run12 , Ve=.042 

A4 
CP 

1c 

0 

-10 

trace 9 

CP 

CP 

-16 -8 0 

x'/d 

8 

trace 11 

10 

0 

.lo 

-1 6 -8 0 

x '/a 

8 

CP 

tract 10 

10 

0 

-10 

-16 -8 0 8 

x'/d 

10 

0 

-10 

trace 12 

-16 -8 0 

x'/d 

8 

Figure A1 . Ground Board Pressure Distribution, Run 12 I Ve=.042 

A5 
trace 2 trace 4 

10 10 

CP 0 CP 0 

-10 -10 

-1 6 8 -1 6 -a 0 a -a 0 

xl/d x'/d 

CP 

-16 -8 0 

x'/d 

trace 7 

8 

10 

0 

-10 

-16 -8 0 

x'/d 

8 

trace 6 

10 

0 

-10 

-16 -8 0 

x'/d 

8 

Figure A2 . Ground Board Pressure Distribution, Run 13, Ve= -043 

A6 
CP 

CP 

trace 9 

10 

0 

-10 

-16 

10 

0 

-10 

-3 . 0 

x'/d 

trace 11 

8 

-16 -8 0 

xl/d 

8 

CP 

CP 

trace 10 

10 

0 

-10 

-16 -8 0 8 

x'/d 

10 

0 

-10 

trace 12 

-16 -a 0 

x'/d 

8 

Figure ~2 . Ground Board Pressure Distribution, Run 13, Ve= .043 

A7 
CP 

CP 

10 

0 

-10 

trace 2 

t i i i i - i i i i i i I i'l 

CP 

-16 

10 

0 

10 

-8 0 8 

x'/d 

trace 5 

-1 6 

10 

0 

-1 0 

-8 0 

x'/d 

8 

-16 -8 0 

x I /d 

8 

CP 

CP 

&! ! ! ! ! ! ! ! ! ! ! ! I 

-10 

-16 

< 

-8 0 8 

x'/d 

trace 6 

10 

0 

-in -- 

-16 -3 0 

x'/d 

8 

Figure A3 . Ground Board Pressure Distribution, Run 14 I Ve= .044 

A8 
trace 9 

10 10 

CP 0 CP 0 

-10 -10 ....,. 

CP 

-16 -8 0 

x'/d 

8 

trace 11 

10 

0 

-10 

-16 -8 0 

x'/d 

8 

CP 

-16 -8 0 

x'/d 

8 

trace 12 

10 

0 

-10 

-16 -8 0 8 

x'/d 

Figure A3 . Ground Board Pressure Distribution, Run 14 I Ve=.044 

A9 
trace 2 trace 4 

CP 

10 

0 

-1 0 Wliii154 .-.. 

-16 -8 0 8 

x'/d 

CP 

-1 6 

10 

0 

-8 0 

x'/d 

trace 7 

8 

-16 -8 0 

x'/d 

8 

CP 

CP 

'1 " ' I 

0 

+!!:!!::!:!!:I 

C"!*'!'!'!'!J 

-16 -a 0 8 

xl/d 

-16 -8 0 

x'/d 

a 

Figure A4 . Ground Board Pressure Distribution, Run 15 , Ve= -053 

A1 0 
10 

CP 0 

-10 

trace 9 

-16 -8 0 

x'/d 

8 

trace 11 

-1 6 -8 0 8 

x'/d 

trace 10 

10 

CP 0 

-10 

-16 -8 0 

x'/d 

8 

10 

trace 12 

CP 0 

-10 

-16 -8 0 8 

x'/d 

Figure A4 . Ground Board Pressure Distribution, Run 15 , Ve=.053 
trace 2 

10 

CP 0 

-10 

CP 

CP 

-16 -8 

10 

0 

,lo 

0 8 

X'/d 

trace 5 

-16 -8 0 

x'/d 

8 

trace 7 

10 

0 

,lo .. 

-16 -a 0 8 

xl/d 

CP 

<!!:!"'""'I 

-1 6 -8 0 8 

x'/d 

trace 6 

10 

0 

-10 

-16 -8 0 

x'/d 

8 

Figure A5 . Ground Board Pressure Distribution, Run 21 I Ve= .041 

A1 2 
CP 

trace 9 

10 

0 

-10 

-16 -8 0 

xl/d 

trace 11 

8 

10 

CP 0 

-10 

-1 6 

CP 

CP 

trace 10 

10 

0 

-10 

-16 -8 0 

xl/d 

8 

10 

0 

-10 -_ 

-8 0 8 

x'/d 

trace 12 

-1 6 -8 0 

x'/d 

8 

Figure A5 . Ground Board Pressure Distribution, Run21 , Ve= .04: 

A1 3 
CP 

CP 

CP 

trace 5 

10 

0 CP 

1111111111 

- -- i ... Fi .. -10 

-16 -8 0 

x'/d 

8 

trace 7 

10 

0 

-8 0 8 

x'/d 

-10 i 1 I i i i 1 I 

-16 

trace 4 

10 

0 

-10 

-1 6 -8 0 8 

x'/d 

trace 6 

10 

0 

-10 

-16 -8 0 8 

x'/d 

Figure A6 . Ground Board Pressure Distribution, Run 22 I Ve=.041 
trace 9 

10 

CP 0 

-10 

trace 10 

-16 -8 0 

x'/d 

8 

trace 11 

10 

CP 0 

-10 

-1 6 -8 0 8 

x'/d 

10 

-16 -8 0 

x'/d 

8 

trace 12 

10 

CP 0 

-10 

-16 -8 0 

x'/d 

8 

Figure ~6 . Ground Board Pressure Distribution, Run 22 Ve=.041 

A1 5 
CP 

CP 

CP 

trace 2 

10 

0 CP 

-10 

-16 -8 0 8 

x'/d 

trace 5 

10 

0 

-10 

-16 -8 0 8 

x'/d 

trace 9 

CP 

10 

0 CP 

-10 

-16 -8 0 

x'/d 

8 

10 

0 

10 

trace 4 

-1 6 -8 0 

xt/d 

trace 6 

8 

-16 -8 0 

x I /d 

8 

trace 10 

10 

0 

-10 

-16 -8 0 8 

xl/d 

Figure ~7 . Ground Board Pressure Distribution, Run 25 , Ve=.10'4 

A1 6 
CP 

10 

0 

10 

trace 2 

-16 -8 0 

x'/d 

8 

trace 5 

CP 

CP 

-16 -8 0 

x'/d 

8 

trace 9 

10 

0 

-10 

-16 -8 0 

x'/d 

8 

trace 4 

10 

CP 0 

-10 

-16 -8 0 8 

x'/d 

trace 6 

10 

CP 0 

-10 

CP 

-16 

10 

0 

-10 

-8 0 

x'/d 

trace 10 

8 

-1 6 -8 0 

x'/d 

8 

Figure ~8 . Ground Board Pressure Distribution, Run 26 , Ve=. [(jb 

AI. 7 
trace 2 

CP 0 

-10 

-1 6 

CP 0 

-1 0 

CP 

-8 0 

x'/d 

trace 5 

8 

-16 -8 0 

x /d 

8 

-16 -8 0 8 

trace 4 

-16 -8 0 8 

x'/d 

10 

CP 0 

-10 

trace 6 

. . . . . . , , , 

CP 

-16 -8 0 

x'/d 

8 

trace 10 

10 

0 

-10 

-16 -8 0 

x'/d 

8 

x'/d 

Figure A9 . Ground Board Pressure Distribution, Run 27 , Ve=.169 

A1 8 
trace 4 

10 

0 

-10 

10 

0 

111111111111 

llllllllllll 

111111111111' 

-10 

CP CP 

-1 6 -8 0 

x'/d 

8 -16 -8 0 

x'/d 

8 

trace 6 

trace 5 

10 

CP 0 

-10 

10 

CP 0 

-10 .... 

-16 -8 0 

x'/d 

8 -16 -8 0 

x'/d 

8 

trace 9 trace 10 

10 10 

CP 0 

-10 

CP 0 

-10 

-1 6 -8 0 

x'/d 

8 -16 -8 0 

x'/d 

8 

Figure ~10 . Ground Board Pressure Distribution, Run 28 , Ve=.187 

A1 9 
trace 2 

10 

CP 0 

-10 

-16 -a 0 8 

x'/d 

CP 

CP 

10 

0 

-10 

trace 5 

-16 -8 0 

xl/d 

8 

trace 7 

10 

0 

-10 

-16 -a 0 8 

x'/d 

CP 

trace 4 

10 

0 

-10 

-16 -8 0 8 

xl/d 

trace 6 

10 

CP 0 

-10 

-16 -a 0 8 

x'/d 

Figure All . Ground Board Pressure Distribution, Run 29 , Ve=..Os5 

A20 
CP 

trace 9 

10 

0 CP 

-10 

-16 -8 0 8 

x'/dtrace 10 

10 

0 

-10 

-16 -8 0 8 

x'/d 

CP 

trace 11 

-16 -8 0 a 

x'/d 

trace 12 

CP 

-a 0 8 

x'/d 

-16 

Figure All . Ground Board Pressure Distribution, Run 29 , Ve=.OCf5 

A2 1 
trace 2 

10 

0 

-10 

trace 4 

10 

0 

-10 

CP 

CP 

CP 

CP 

-16 -8 0 

xl/d 

- 

8 

trace 5 

10 

0 

.. - - -{:ZtZ] 

-10 ES=K !- t -- I ij ; ....... .. 

-16 -8 0 8 

x'/d 

trace 9 

10 

0 

-10 

-16 -8 0 

x'/d 

8 

C 

-16 -8 0 

xl/d 

8 

trace 6 

10 

P 0 

. . . . . . , -10 

CP 

-16 -8 0 

x'/d 

8 

trace: 10 

10 

0 

-10 

-16 -a 0 

x'/d 

8 

Figure A12 . Ground Board Pressure Distribution, Run 31 , Ve=.174 

A22 
trace 2 

10 

CP 0 

-10 

-1 6 -8 0 

x'/d 

8 

trace 5 

10 

CP 0 

-10 

10 

CP 0 

-10 

-16 -8 0 

x'/d 

8 

trace! 4 

10 

CP 0 

-10 

-16 -8 0 

x'/d 

8 

10 

trace 6 

-10 

trace 9 

10 

CP 0 

q,. 

-1 6 -8 0 

x '/d 

8 

-16 -8 0 

x'/d 

8 

trace: 10 

JlIll!l!!!!!!~ 

-1u 

-16 -a 0 8 

x'/d 

Figure ~13. Ground Board Pressure Distribution, Run 32 , Ve= .I73 

A2 3 
trace 2 

10 

CP 0 

-10 

CP 

CP 

-16 -8 0 

x'/d 

8 

10 

trace 5 

CP 

0 CP 

-1 0 

-16 -8 0 

xl/d 

8 

trace 9 

C 

-1 6 -8 0 

x'/d 

8 

trace! 4 

10 

0 

-10 

-16 -8 0 

x I /d 

8 

trace 6 

10 

0 

-10 

-16 -8 0 8 

x I /d 

trace. 10 

10 

0 

-10 

-16 -8 0 

x'/d 

8 

Figure A14. Ground Board Pressure Distribution, Run 40, Ve=.187 

A24 
trace 2 

10 

CP CP 0 

-10 

CP 

CP 

-16 -8 0 8 

xl/d 

trace 5 

10 

CP 0 

..... ,...,, -1 0 

-1 6 -a 0 

x'/d 

trace 7 

8 

10 

-1 0 

-16 -a 0 

xl/d 

8 

trace 4 . lo 

0 

-10- ' ' " - ' ; + 

-1 6 

10 

0 

-10 

-a 0 

x ' /d 

tracc 6 

8 

-16 -a 0 

x /d 

8 

Figure A15. Ground Board Pressure Distribution, Run 42 , Ve=.088 

A2 5 
CP 

CP 

trace 9 

-16 -8 0 8 

xt/d 

trace 11 

CP 

10 

0 CP 

-10 

-1 6 -8 0 

xt/d 

8 

trace: 10 

10 

0 

-10 

-16 -8 0 8 

x'/d 

trace 12 

10 

0 

-10 

-16 -8 0 

x'/d 

8 

Figure A15. Ground Board Pressure Distribution, Run 42 , Ve=.088 

A2 6 
trace 2 

10 

:P 0 

-10 

C 

-1 6 -8 0 8 

x '/d 

trace 5 

CP 

IIlIllll 

-16 -8 0 

x'/d 

8 

CP 

-16 -8 0 

x'/d 

8 

trace! 4 

10 

CP 0 

-10 

-16 -8 0 8 

x'/d 

trace 6 

10 

CP 0 

-10 

-16 -8 0 8 

x ' /a 

Figure A16. Ground Board Pressure Distribution, Run 43 , Ve=.OoO 

A2 7 
trace: 10 

10 

0 

-10 

CP 

-16 -8 0 

x'/d 

8 

trace 11 

10 

0 

-10 

-1 6 -8 0 8 

x'/d 

CP 

-16 -8 0 

x'/d 

trace 12 

8 

10 

0 

-10 

-16 -8 0 8 

xl/d 

Figure ~16. Ground Board Pressure Distribution, Run 43 , Ve=.0911 

A28 
APPENDIX B 

. BASIC DATA FOR THE 0.6 INCH NOZZLE CONFIGURATION 
APPENDIX B 

LIST OF FIGURES 

FIGURE TITLE 

B1. Ground Board Pressure Distribution, 

Run 66, Ve=0.080. 

B2. Ground Board Pressure Distribution, 

Run 67, Ve=0.084. 

B3. Ground Board Pressure Distribution, 

Run 69, Ve=0.107. 

B4. Ground Board Pressure Distribution, 

Run 73, Ve=0.132. 

B5. Ground Board Pressure Distribution, 

Run 74, Ve=0.093. 

LIST OF TABLES 

TABLE TITLE 

B1 INSTRUMENTATION LOCATION 

PAGE 

B3 

B3 

B3 

B4 

B4 

PAGE 

82 
TABLE B1. INSTRUMENTATION LOCATION 

TAP II X Y 

7 

8 

9 

10 

-10.5 FEET 0 NOT AVAILP-RLE 

-0.5 FEET 0 NOT AVAILARLE 

25.0 FEET 2.0 INCHES 

25.0 FEET 0 

1-25 st.-* I 

R2 
trace 10 

. 

10 

CP 0 

-10 

-16 -8 0 8 

x /d 

Figure B1. Ground Board Pressure 

10 

CP 0 

trace 

t i i i i-i i i --. 

-lo! ! ! ! ! ! !! f! 

-1 6 -8 0 8 

x'/d 

Figure B2. Ground Board Pressure 

trace g 

CP 

-16 -8 0 8 

x'/d 

10 

CP 0 

-10 

-16 -8 0 8 

xt/d 

Distribution, Run 66, Ve=0.080. 

trace 10 

10 

CP 0 

I I I I I I ir'ii 

-lo! ! ! ! I I ! ! ! ! t-! , , 

-1 6 -8 0 8 

xt/d 

Distribution, Run 67, Ve=0.084. 

trace 10 

10 

CP 0 

-10 

-1 6 -a 0 8 

xt/d 

Figure B3. Ground Board Pressure Distribution, Run 69, Ve=0.107. 

B3 
CP 

trace 9 

10 

0 

-10 

-16 -8 0 

xl/d 

8 

CP 

trace 10 10 

0 

-10' 

-16 -8 0 

xl/d 

8 

Figure B4. Ground Board Pressure Distribution, Run 73, Ve=0.132. 

CP 

trace 9 

10 

0 

-10 

-16 -8 0 

x'/d 

8 

Figure B5. Ground Board Pressure 

10 

CP 0 

-10 

Ill1 

1 I I I, 

-16 -8 0 

x'/d 

8 

Distribution, Run 74, Ve=0.093. 

B4 
APPENDIX C 

NOZZLE SURVEY DATA 
APPENDIX C 

LIST OF FIGURES 

FIGURE TITLE PAGE 

c1 

c2 

c3 

c4 

c5 

C6 

c7 

C8 

c9 

c10 

c11 

c12 

C13 

C14 

C15 

C16 

C17 

C18 

c19 

c20 

c21 

c22 

C23 

C24 

Nozzle Exit Pressure Survey, 0.6", h/d=0.2 

Q jet=634 

Nozzle Exit Pressure Survey, 0.6", h/d=0.2 

Q jet=1054 

Nozzle Exit Pressure Survey, 0.6", h/d=0.2 

Q jet=1337 

Nozzle Exit Pressure Survey, 0.6", h/d=l.O 

Q jet=634 

Nozzle Exit Pressure Survey, 0.6", h/d=l.O 

Q jet=1054 

Nozzle Exit Pressure Survey, 0.6", h/d=l.O 

Q jet=1337 

Nozzle Exit Pressure Survey, 0.6", h/d=3.0 

Q jet=634 

Nozzle Exit Pressure Survey, 0.6", h/d=3.0 

Q jet=1054 

Nozzle Exit Pressure Survey, 0.6", h/d=3.0 

Q jet=1337 

Nozzle Exit Pressure Survey, 0.6", h/d=lO.O 

Q jet=634 

Nozzle Exit Pressure Survey, 0.6", h/d=lO.O 

Q jet=1054 

Nozzle Exit Pressure Survey, 0.6", h/d=lO.O 

Q jet=1337 

Nozzle Exit Pressure Survey, 1.0", h/d=0.2 

Q jet=85 

Nozzle Exit Pressure Survey, l.O", h/d=0.2 

Q jet=265 

Nozzle Exit Pressure Survey, l.O", h/d=0.2 

Q jet=935 

Nozzle Exit Pressure Survey, 1.0", h/d=l.O 

Q jet=85 

Nozzle Exit Pressure Survey, l.O", h/d=l.O 

Q Jet=265 

Nozzle Exit Pressure Survey, l.O", h/d=l.O 

Q Jet=935 

Nozzle Exit Pressure Survey, 1.0, h/d=3.0 

Q jet=85 

Nozzle Exit Pressure SurveyI 1.0, h/d=3.0 

Q jet=265 

Nozzle Exit Pressure SurveyI 1.0, h/d=3.0 

Q jet=935 

Nozzle Exit Pressure Survey, 1.0", h/d=lO.O 

Q jet=85 

Nozzle Exit Pressure Survey, 1.0", h/d=lO.O 

Q jet=265 

Nozzle Exit Pressure Survey, 1.0", h/d=lO.O 

Q jet=935 

e2 

c3 

c4 

c5 

C6 

c7 

C8 

c9 

c10 

c11 

c12 

C13 

C14 

C15 

C16 

C17 

C18 

c19 

c20 

c21 

c22 

C23 

C24 

C26 

c1 
e 

U 

W 

n 

!i 0.7 

0.6 

0.9 

0.8 

1.1 

1.2 

la3 

1,4 

1 

, 

0.5 

0.4 

0,3 

0.2 

0.1 

0 

o y/d=O 

-0.17 

0 -0.33 

A -0.50 

x -0.67 

V -0.83 

-0.8 -0.4 0 0.4 0.8 1.2 -1.2 

x/d 

1.5 

1.4 1 

0 y/d=O t 0 .'17 

0 0.33 

A 0.50 

x 0.67 

V 0 . I% 3 

0 0.4 1.2 -1.2 -0.8 -0.4 

X/d 

Figure C1. Nozzle Exit Pressure Survey, 0.6", h/d=0.2 

Q Jet=634 

c2 c'- - 3- 
0 y/d=O 

t -0.17 

0 - 0 . 7 .I 

A -0.50 

x -0.6? 1 

0 -0.83 

-0 -8 -0.4 0 0.4 0.8 12 -1 2 

x/d 

Figure C2. Nozzle Exit Pressure Survey, 0.6", h/d=0.2 

Q Jet=1054 

c3 
-1 2 -0.8 -0.4 0.4 0.8 1.2 

0 y/d=O 

+ 3.17 

0 0.33 

A 0.50 

X 0.67 

0 0.83 

-0.8 -0.4 0 0.4 08 1.2 -1 2 

X/d 

Figure C3. Nozzle Exit Pressure Survey, 0.6", h/d=0.2 

Q Jet=1337 

c4 
0.8 

0.9 

1.3 

1,l 

::: 1.2 

1 

I 

0.7 

0.6 

0.5 

0.4 

0,3 

0.2 

0.1 

0 

1 

0 y/d=O 

t -0.17 

0 -0.33 

0 -0.50 

x -0.67 

V -0.83 / 

-0.8 -0.4 0 0.4 0.8 1.2 -1.2 

1.2 

1'3 1 

0.3 

0.4 4 

1.3 

1.2 

1.1 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

-1.2 

Figure C4. 

0 y/d=O 

t 0.17 

0 0.33 

A 0.50 

X 0.67 

0 0.83 

-0.8 -0.4 0 0.4 0.8 

x/d 

1.2 

Nozzle Exit Pressure Survey, 0.6", h/d=l.O 

Q jet=634 

c5 
0.5 - 

0.4 - 

0,3 - 

0.2 - 

0.1 - 

5 

U 

a 

IJ 

w 

x/d 

1.5 

1.4 

1.3 

1.2 

1.1 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

-0.4 0 0.4 0 8 1.2 -1.2 -0.8 

X/d 

Figure C5; Nozzle Exit Pressure Survey, 0.6", h/d=l.O 

Q jet=1054 

C6 
1.3 

1'4 4 0 y/d=O 

+ -0.17 

0 -0.33 

A -0.50 

x -0.67 

V -0.83 

-0.8 -0.4 0 0.8 1.2 -1.2 

1.4 1 

1.3 4 0 y/d=O 

0.4 0.8 1.2 -0.8 -0.4 0 -1.2 

x/d 

Figure C6; Nozzle Exit Pressure Survey, 0.6", h/d=l.O 

Q Jet=1337 

c7 
1.5 

1.4 

1.3 

1.2 0 y/d=O 

+ -0.33 

0 -0.67 

Y -1.33 

1.1 

1 b -1 .OD 

V -1 .67, 0,9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

-0.5 0.5 1.5 2.5 -2.5 -1.5 

1,4 - 

1,3 - 

1.2 - 

1,l - 

x/d 

1.5 

0 yld-0 

+ 0.33 

0 0.67 

1.00 A 

1.33 X 

1.67 0 

Figure C7; Nozzle Exit Pressure Survey, 0.6", h/d=3.0 

Q jet=634 

C8 
Figure C8; Nozzle Exit Pressure Survey? 0.6"? h/d=3.0 

Q jet=1054 

c9 
1-5 

1.4 

1.3 

1.2 

1.1 

1 

0.9 

0,8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

0 y/d=O 

t -0.33 

0 -0.67 

A -1.00 

x -1.33 

0 -1.67 

u- T- I- T- I- 7 -1- .r - 

-2.5 -1 5 -0.5 0.5 1.5 2.5 

0 Yfd4 

.t 0.33 

0 0.67 

1.00 

1.33 

1.67 

A 

x 

V 

-1.5 -0.5 0.5 2.5 -2.5 

x/d 

- 

15 

Figure C9; Nozzle Exit Pressure Survey, 0.6", h/d=3.0 

Q jet=1337 
0.3 

0.2 

0.1 

0 

0 y/d=O 

-t 0.33 

0 0.67 

1.00 

1.33 

1.67 

A 

X 

V 

Figure C10; Nozzle Exit Pressure Survey, 0.6", h/d=19.0 

Q jet-634 

c1 I 
1.4 - 

1.3 - 

1.2 - 

'*I 1 4 a y/d=O 

+ -0.33 

0 -0.67 

A -1 .oo 

x -1.33 V - I .67 

0.4 

0.3 

0.2 

0,l 

0 

x/d 

Figure C11; Nozzle Exit Pressure Survey, 0.6", h/d=lO.O 

Q Jet=1054 

c1 2 
1.5 

1.4 

1.3 

1.2 

1.1 

1 

0.9 

s 0,8 

a 

k! 

0.7 

0.6 

0.5 

0,4 

0.3 

0.2 

0.1 

0 

I- J 

-1 .!3 -0.5 0.5 1.5 2.5 -2.5 

x/d 

1.5 

1.4 

1.3 

12 

1.1 

1 

OS9 

s 0.8 

5 07 

0,6 

0.5 

0.4 

0.3 

02 

0.1 

0 

a 

15 25 -2 5 -1 5 -0 5 

x/d 

i ' 

Figure C12; Nozzle Exit Pressure Survey, 0.6", h/d=lO.O 

Q jet=1337 

C13 
1.5 

1.4 - 

1.3 - 

1.2 - 

1.1 - 

1- 

0.9 - 

0.2 0.6 1 1.4 

0 y/d=O 

+ 0.20 

9 0.40 

A 0.60 

X 0.80 

0 1.80 

Figure C13; Nozzle Exit Pressure Survey, 1.0", h/d=0.2 

Q jet=85 

C14 
1,4 -8 

1.3 - 

1.2 - 

0 y/d=O 

+ -0.20 

0 -0.40 

4 -0.60 

r: -0.80 

V -1 .oo 

1 

- 

r - .c v ~ 

1,4 - 

1.3 - 

1,2 - 

-0.2 0.2 0.6 1 1.4 -1.4 -1 -0.6 

o yld-0 

+ 0.20 

0 0.40 

A 0.60 

X 0.80 

0 1.80 

0.4 0.8 1.2 

Figure C14; Nozzle Exit Pressure Survey, 1.0", h/d=0.2 

Q jet=265 

"'\ 

C15 
1.5 

::: 1 

1.2 

1.1 j 

0 y/d=O 

f- -0.20 

0 -0.40 

-(J. 60 

-0.80 

V -1 .oo 

B 

U 

I- J 

-1.4 -1 -0-6 -0.2 

x/d 

1.4 

1.2 

la3 

1.1 

4 4 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

0 y/d=O 

+ 0.20 

0 0.40 

0-2 0.6 1 1.4 

1 

-1.2 -0.8 -0.4 0 0.4 0.8 1.2 

X/d 

Figure C15: Nozzle Exit Pressure Survey, l.O", h/d=0.2 

Q jet=935 

C16 
1.5 

1.3 lS4 1 

::: 1 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

1.5 

1.4 

1.3 

1.2 

1.1 

1 

0,9 

0.8 

0.7 

0.6 

0.5 

0,4 

0.3 

0.2 

0.1 

0 

o y/d=Q 

t -0.20 

0 -0.40 

h -0.00 

x -0.80 

V -1.00 

-1.4 -1 -0.6 -0.2 0.2 0.6 1 

. - - x/d 

0 y/d=O 

+ 0.20 

0 0.40 

A 0.60 

X 0.80 

0 I. 80 

1.4 

1 

-1.2 -0.8 -0.4 0 0.4 0.8 1.2 

x/d 

Figure C16; Nozzle Exit Pressure Survey, 1.0", h/d=l.O 

Q jet=85 

C17 
1.5 

1,4 - 

1.3 - 

1.2 - 

1,l - 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

-1.4 -1 -0.6 -0.2 

X/d 

1.5 

1.4 

1.3 

1.2 

1.1 

1 

os9 

0,8 

0,7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

0 y/d=O 

f -0.20 

0 -0.40 

-0.60 

x -0.80 

0 -1 .00 

1 

0 y/d=O 

+ 0.20 

0 0.40 

1 

-1.2 -0.8 -0.4 0 0.4 0.8 1.2 

x/d 

Figure C17; Nozzle Exit Pressure Survey, 1.0", h/d=l.O 

jet=265 

C18 
-1.2 -0.8 -0.4 0 0.4 0.8 1.2 

Figure C18; Nozzle Exit Pressure Survey, 1.0", h/d=l.O 

Q jet=935 

c19 
1.5 

1,4 

n y/tl=O 

t -0.20 1.3 

I .2 0 -0.40 

b -0.60 

x -0.80 1.1 

1 0 -1 .oo 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

U 

c 

-1 

E 

1.4 - 

1.3 - 0 yld-0 

1.2 

1,l 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

-3 -1 1 

x/d 

+ 0.20 

9 0.40 

A 0.60 

x 0.80 

V 1.80 

3 

Figure C19; Nozzle Exit Pressure Surveyl l.Ol h/d=3.0 

Q jet=85 

c20 
. 

- 

- 

- 

- 

1.5 

1.4 

1.3 

1.2 

1.1 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

0 y!d=O 

+ -0.20 

0 -0.40 

-0.60 

x -0.80 

A 

1.5 

1.4 

1.3 

1.2 

1.1 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0,4 

0.3 

0.2 

0.1 

0 

-3 -1 1 3 

x/d 

Nozzle Exit Pressure Surveyf l.Of h/d=3.0 

Q Jet=265 

Figure C20; 

c2 1 
1,5 

1.4 

1.3 

1.2 

1.1 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

1.5 

1,4 

1.3 

1.2 

1,l 

1 

0,9 

0.8 

0.7 

0,6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

I 1 

0 y/d=O 

t -0.20 

0 - I . 4 0 

A -0.60 

0 -1.00 

I 1 7" 1 

-3 -1 1 

x/d , 

-I 1 

-3 -1 

X/d 

0 17 /*I=O 

+ 0.20 

0 0.40 

3 0.60 

X 0.80 

V 1.80 

1 

3 

3 

Figure C21; Nozzle Exit Pressuro Survey, 1.0, h/d=j.O 

Q Jet=935 

c22 
“ 

. 0.7 

0.6 

4 

c 

J 

W 

0 

0.2 

0.1 

0 y/d=O 

t -0.20 

0 -0.40 

A -0.60 

x -0.80 

V -1.00 

0 y/d=O 

+ 0.20 

0 0.40 

A 0. bo 

X 0.80 

V 1. 

0,3 

0.2 

0.1 

0 

-3 -1 

X/d 

1 3 

Figure C22; Nozzle Exit Pressure Survey, 1.0”, h/d=lO.O 

Q jet=85 

C23 
5 

4 

W 

a 

3 

X/d 

Figure C22; Nozzle Exit Pressure Survey, 1.0", h/d=lO.O 

Q jet=85 (Cont.) 

1.5 

1.4 

1.3 

I 

, 1.2 

I 

1.1 

1 

0.9 

H 08 

4 

5 0.7 

w 

0 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

I 

I -- 1 1 

-1 1 3 x/d 

-3 

Figure C23; Nozzle Exit Pressure Survey, 1.0", h/d=lO.O 

Q jet=265 

. 

. 

C24 
1,4 - 

1.3 - 

1.2 - 

1,l - 

1- 

0.9 - 

$ 0.8 - 

a 

5 0.7 - 

W 

0 

0.6 - 

I 

h 

U 

5 

0” 

. x/d 1.5 I 

0 y/d=O 

+ 0.20 

0 0.40 

A. 0.60 

X 0.80 

0 1.80 

-3 

I 

-1 

x/d 

1 3 

Figure C23; Nozzle Exit Pressure Survey, 1.0”, h/d=lO.O 

Q jet=265 (Cont.) 

C25 
1 .s 

1,4 

1,3 

1.2 

1.1 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0,3 

0.2 

0.1 

0 

s 0,8 

0.6 

4 

5 

w 

a 

1 

Os' 0 t 

o y/d=G 

t 0.20 

0 0.40 

A 0.60 

X 0.80 

0 1.80 

-3 -1 1 3 

x/d 

Figure C24; Nozzle Exit Pressure Survey, 1.0", h/d=lO.O 

Q jet=935 

C26 
5 

1 .s i 

1.2 

1,l 

0 y/d=O 

t -1.20 

0 -1.40 

A. 1.20 

X 1.40 

0.4 

0,3 

0.2 

0.1 

0 

-3 -1 1 3 

x/d 

Figure C24; Nozzle Exit Pressure Survey, 1.0", h/d=lO.O 

Q jet=935 (Cont.) 

4 

C27 
Report Documentation Page 

1. Report No. 

NASA CR-181841 

2. Government Accession No. 

4. Title and Subtitle 

s pegel 21. No. of pages 

128 

An Experimental Investigation of the Ground Vortex 

Created by a Moving Jet 

22. Price 

A07 

7. Authorkt 

19. Security Classif. (of this report) 

V. R. Stewart 

20. Security Classif. (of t 

9. Performing Organization Name and Address 

V. R. Stewart, Consultant 

5689 Plum Orchard Drive 

Columbus, OH 43213 

2. Sponsoring Agency Name and Address 

National Aeronautics and Space Achninistration 

Langley Research Center 

Hampton, VA 23665-5225 

5. Supplementary Notes 

3. Recipient’s Catalog No. 

5. Report Date 

Julv 1989 

6. Performing Organization Code 

-. 

8. Performing Organization Report No. 

VS 1-88 

10. Work Unit No. 

503-61-7142 

11. Contract or Grant No. 

G29341C 

13. Type of Repon and Period Covered 

Contractor Report 

14. Sponsoring 4gency Coda 

Langley Technical Monitor: G. T. Kemnerly 

6. Abstract 

An experimental investigation of a 1 inch circular jet moving over a fixed 

pund board has been conducted in the NASA Langley Research Center Vortex 

Research Center. 

nozzle diameters creates a ground vortex which was measured by a pattern of 

Endevco high response pressure transducers. 

existing data to determine the effect of the ground boundary eliminated by the 

moving jet. The penetration of the vortex both forward of and latterly to the 

impact point of the jet on the ground. 

The jet passing over the ground board at a height of three 

The results are clrpared to 

The resulting ground vortex penetration forward of the impact point is reduced 

by approximately 30 percent and the lateral penetration is reduced by 50 percent 

over that experienced fran a stationary jet over a stationary ground board with 

a free stream velocity. 

17. Key Words (Suggested by Authodst) 

Ground Effect 

Ground Vortex 

Moving Jet 

Dynamic Variations of Pressure 

Unclassified I Unclassified 

I_- 

18. Dmtribution Statement 

I I 1 

lASA FORM 1628 OCT 86 

.. 

.