NASA Contractor Report 182232 - 

Noise Generated by a Flight Weight, Air 

Flow Control Valve in a Vertical 

Takeoff and Landing Aircraft 

Thrust Vectoring System 

Ronald G. Huff 

Sverdrup Technology, Inc. 

NASA Lewis Research Center Group 

Cleveland, Ohio 

February 1989 

Prepared for 

Lewis Research Center 

Under Contract NAS3-25266 

National Aeronautics and 

Space Administration 
NOISE GENERATED BY A FLIGHT WEIGHT, AIR FLOW CONTROL VALVE IN A VERTICAL 

TAKEOFF AND LANDING AIRCRAFT THRUST VECTORING SYSTEM 

Ronald G. Huff 

Ronald G. Huff and Associates 

Engineering Consultants 

6137 Sherwood Dr. 

North Olmsted, Ohio 44070 

SUMMARY 

Tests were conducted in the NASA Lewis Research Center's Powered Lift 

Facility to experimentally evaluate the noise generated by a flight weight, 

12 in. butterfly valve installed in a proposed vertical takeoff and landing 

thrust vectoring system. Fluctuating pressure measurements were made in the 

circular duct upstream and downstream of the valve. 

the results of these tests. The maximum overall sound pressure level is generated in the duct downstream of the valve and reached a value of 180 dB at a 

valve pressure ratio of 2.8. 

downstream of the valve is broad banded with its maximum at 1000 Ht. 

This data report presents 

At the higher valve pressure ratios the spectra 

INTRODUCTION 

Noise generated in military aircraft can be a major problem if it interFatigue, due to excessive noise can also be a problem during long duraNoise protection offered by acoustically treated helmets appear 

feres with radio communication with the pilot or creates a permanent hearing 

loss. 

tion flights. 

to be reaching a limit. Vertical takeoff and landing aircraft have high external noise levels during hovering flight. In this mode the thrust is vectored 

by throttling the flow between vertical and horizontal nozzles. The valves 

used to throttle the flow generate additional noise inslde the aircraft that 

may be transmitted to the cockpit thus acting as a noise source that directly 

affects the pi lot. 

Tests were conducted in the NASA Lewis Research Center's Powered Lift 

Facility to experimentally evaluate the noise generated by a flight weight, 

12 in., butterfly valve installed in a proposed vertical takeoff and landing 

thrust vectoring system. Fluctuating pressure measurements were made in the 

circular duct upstream and downstream of the valve. 

the results of these tests. 

This data report presents 

APPARATUS 

An aerial photograph of the Powered Lift Facility (PLF) is shown in figAir is provided by the NASA Lewls Research Cenure 1. 

during the valve noise tests. 

ter's Central air handling facility through an underground piping system to a 

point shown at the upper right corner of the schematic shown in figure 2. A 

The test stand has thrust measurement capability that was not used 
positive shut off gate valve is located just above the ground and is used to 

isolate the rig from the central supply system when the rig is not in operation. When PLF is operating this gate valve is completely open and is not 

expected to generate significant noise levels. Following the gate valve, the 

flow passes through two 90" elbows and then through a venturi used to measure 

the mass flow rate through the facility. Downstream of the venturi, the flow 

encounters the first flow control valve. Downstream of this valve, a tee 

allows the flow to be split between two pipes. The smaller pipe leads to an 

in line 557 combustor can, used to heat the air supplied to the test hardware. 

Downstream of the tee, a 90" elbow is installed in the smaller pipe allowing 

the pipe to be run parallel to the large pipe. Butterfly valves are installed 

in both the large and small pipes to allow the flow through each of the pipes 

to be independently controlled. Downstream of the burner, the bypass flow 

passes through a 90" elbow and rejoins the flow in the larger pipe. 

burner was not used for these cold flow tests. 

The 

The merged flow passes through two 90" elbows and then to a tee located 

at the test stand. At the tee, the flow is split as shown in figure 2. Each 

half passes through two 90" elbows and then through bellows to another tee 

where the flow enters the floating portion of the test stand through a single 

pipe. 

leading to the floating portion of the test rig to accommodate the thrust measurement. A flow straightener is installed in the straight pipe downstream of 

the tee. No acoustic mufflers or noise suppression devices were installed in 

the piping to suppress the internally generated noise during these tests. 

The bellows were installed to isolate the test hardware from the piping 

The test hardware is shown pictorially in figure 3. The test hardware is 

connected to the facility piping immediately downstream of the last facility 

pipe tee. A schematic of the test hardware is shown in figure 4. The test 

hardware consist of a pipe leading to a plenum chamber. A perforated pipe is 

inserted inside the plenum chamber as shown in figure 4 to help distribute the 

flow in the plenum and to facilitate its entry into the pipe leading to the 

12 in. butterfly valve. This valve is used to throttle the flow to the vertical thrust nozzles. For these tests the pipe leading to the horizontal thrust 

nozzle is blanked off. In the actual flight version another valve would exist 

in that pipe and would, in conjunction with the test valve, provide the mechanism for splitting the flow between the vertical and horizontal nozzles for 

thrust vectoring purposes. The pipe wall thickness was one-eighth inch and 

therefore can be expected to transmit a large part of the pressure disturbances 

in the pipe to its surroundings. 

INSTRUMENTATION 

Aerodynamic 

Aerodynamics instrumentation provided for measurement of the air mass 

flow rate using a venturi installed in the main supply pipe upstream of the 

burner bypass pipe tee. 

upstream of the test hardware. Barometric pressure was recorded. A1 1 aerodynamic measurements were recorded using a central data processing system. 

Air total temperature and pressure were measured 

2 
Acous t i c 

The acoustic instrumentation consisted of four internal pipe fluctuating 

pressures pickups. The pressure transducers used to measure the fluctuating 

wall static pressures in the pipe, were set up to read the differential pressure between the transducer face mounted flush at the inside surface of the 

pipe and a static pressure tap placed in the pipe near the transducer face. A 

long length of tubing was connected between the transducer reference side and 

the static tap thus damping the dynamic pressure component coming from the 

tap, figure 5. 

The transducers were installed in pairs spaced a half pipe diameter apart 

along the pipe axial direction, figure 4. Pairs of transducers were installed 

at two axial locations in the pipe, one pair upstream of the valve and the 

other downstream of the valve. The first transducer in each pair is placed at 

one pipe diameter from the valve. 

The output from the pressure transducer was passed through a signal conditioner and then to a linear amplifier. To eliminate electrical noise in the 

signal a 10 kHz low pass filter was used at the amplifier. Therefore, all of 

the transducer data is limited to frequencies at or below 10 kHz. The output 

from the transducer amplifiers were recorded on FM tape for off line data 

reduction. 

DATA REDUCTION 

Aerodynamic 

The aerodynamic data was recorded using the central data processing 

facility located at NASA Lewis for post run computer processing. A computer 

located at this facility later reduced the data to engineering units and produced the required output. Mass flow rates were calculated as was the valve 

pressure ratio. Table I list the reading numbers, valve pressure ratios, and 

upstream total pressure and mass flow rate. 

&oust i c 

The acoustic data was recorded on FM tape for post run analysis. Spectral analysis was performed on a Rockland third octave analyzer and transmitted 

to the central data processing facility for computer processing. 

octave and overall sound pressure level data were processed and tabulated using 

an existing acoustic data reduction program. 

spectra are shown in the appendix for record purposes. The overall sound pressure level (OASPL) data are tabulated in table I1 along with the reading numbers and nozzle pressure ratios. 

The third 

Plots of all the third octave 

EXPERIMENTAL PROCEDURE 

The 

was as follows. 

angular position. 

the upstream flow control valve so that the ratio of the total pressure upstream 

procedure followed to obtain the valve noise data presented herein 

First the valve was set manually and locked at a predetermined 

Then the mass flow rate through the valve was adjusted using 

3 
of the 12 in. test valve to the atmospheric pressure downstream of the valve 

equaled the desired set point pressure ratio. After the flow stabilized the 

amplifier gains for each of the transducers were adjusted to eliminate signal 

clipping but insure adequate signal at the tape recorder input. The gains were 

then recorded manually and a 2 min recording of the signals was made for post 

run analysis purposes. This procedure was followed for valve angular positions 

of 30", 37.5", 45", 52.5", 60", 75" and 90" with nominal valve pressure ratios 

covering the range of 1.4, 1.8, 2.0, 2.4, and 2.8. Valve angular positions 

less than 30" were prohibited due to geometric restriction on the valve adjustment mechanism. 

RESULTS AND DISCUSSION 

Overall Sound Pressure Level 

The overall sound pressure level is shown in figure 6 as a function of 

valve angular position for each of the valve pressure ratios set during these 

tests. Figures 6(a> to (d) show the OASPL for transducer numbers 1 to 4 

respectively. 

starts at a relatively low level and increases to a maximum of 156 dB between 

the 50" and 60" valve positions and then decreased. Downstream of the valve, 

figures 6(c) and (d> the OASPL at 30" starts at a relatively high level and 

peaks 180 dB at angular position less than 60". The general conclusion is that 

the overall sound pressure level for this test valve reaches a maximum at a 

midrange valve angular position and falls off on either side of this maximum. 

At the upstream locations, figures 6(a> and (b> the OASPL at 30" 

To compare the upstream to the downstream overall sound pressure levels 

the OASPL were plotted at these locations as a function of valve angular position, figure 7. The data are shown for nominal valve pressure ratios of 1.4, 

1.8, 2.0, 2.4 and 2.8 in figures 7(a> to (e), respectively . The downstream 

OASPL are always significantly higher than the upstream levels except when the 

valve is completely open. This is the result of the noise being generated in 

the region downstream of the butterfly disc where the flow separates creating 

turbulence and thus generating noise that is similar to that generated by a 

jet in its shear layer. As the valve is opened the size of the separated 

region downstream of the valve disc decreases and the noise diminishes. With 

the valve at the fully open position, 96", the separated region minimizes and 

the downstream noise approaches the upstream levels. 

For comparison a plot having the same parameters as figure 7 but for a 

54 in. butterfly valve used to control the flow from the NASA Lewis Research 

Center's 8- by 6-Foot Supersonic Wind Tunnel plenum chamber is shown in figure 8. The data were taken from reference 1. Comparison of the downstream 

OASPL, transducer numbers 1 and 2 to the upstream transducer numbers 3 and 4 

show the same trends as the current test data. Transducer numbers 5 and 6 were 

microphones placed in the plenum chamber upstream of the pipe bellmouth and 

exhibit the same shape as the internal pipe transducers. The level is lower 

due to the spherical spreading of the sound waves as they leave the bellmouth. 

Figure 7(e> shows that maximum noise levels in the pipe downstream of 

the valve can reach 180 dB. Steel pipe with wall thickness on the order of a 

quarter inch are expected to cause a transmission loss of about 20 dB. Since 

the pipe wall is half this thickness its mass will not produce as much attenuation. Thus, the level in the fuselage from the valve can be expected to be on 

4 
the order of 160 dB or greater. If the fuselage is considered to be a reverberant chamber the pilot will be exposed to this level. If the pilot's helmet 

further reduces the level by 30 d6 the pilot would be exposed to 130 dB, the 

so called threshold of pain. From this scenario it is obvious that acoustic 

treatment will be required if this valve configuration is employed in flight 

hardware. 

One-Third Octave Spectra 

Typical spectra are shown in figure 9 for the upstream and downstream 

transducers at a valve pressure ratio of 1.4. 

broad-banded maximums between 200 and 1000 Hz. Estimates of peak jet noise 

frequency, based on a 1 ft diameter and a Strouhal number of 0.2, 160 Hz, 

(band number 22). If the diameter is assumed to be a half foot the frequency 

is 320 Hz (band number 25). These frequencies are on the order of those shown 

in figure 9. Spectral weighting curves used to evaluate the spectra for the 

response of the human ear decrease the sound pressure levels (SPL) below a frequency of 1000 Hz. This would be a benefit to the "A" weighted sound level. 

However the spectra are broad banded and have high SPL above 1000 Hz so that 

the decrease is not expected to be significant. 

The downstream spectra have 

Upstream of the valve the spectra is less smooth with a peak at 80 Hz 

(band number 19) and a broad banded maximum just above 1000 Hz (band number 

30). 

At the higher valve pressure ratios, figure 10, the downstream spectra 

again have broad banded maximums but peak at about 1000 Hz, a higher frequency 

then the low pressure condition, figure 9. The "A" weighting of this spectra 

will have little affect on the OASPL value so that the value of the OASPL may 

be assumed equal to the "A" weighted sound level. 

Upstream of the valve the spectra shows a peak that probably is a tone 

at a frequency of 630 Hz (band number 28). The spectra are relatively flat 

but as irregular as the low pressure ratio spectra shown in figure 9. 

CONCLUDING REMARKS 

During transition from vertical takeoff to normal flight high noise levels can be expected from the thrust vectoring system. With noise levels 

approaching 180 dB in the ducting system leading to the forward end of the 

fuselage and thin wall ducts the noise level in the fuselage is expected to 

reach at least 160 dB. Thus, it is clear that acoustic treatment will be 

required to lower the level to an acceptable level in the cockpit to avoid 

interference with pilot communication, pilot fatigue and permanent hearing 

loss problems. 

CONCLUSIONS 

Noise levels generated by a flight weight, 12 in. butterfly valve applicable to a vertical take off and landing aircraft thrust vectoring control system were determined experimentally. The measurements were taken in the duct 

both upstream and downstream of the valve. 

drawn : 

The following conclusions are 

5 
1. The maximum overall sound pressure level is generated in the duct 

downstream of the valve and reached a value of 180 dB at a nozzle pressure 

ratio of 2.8. 

2. At the higher valve pressure ratios the spectra downstream of the 

valve is broad banded with its maximum at 1000 Hz. 

3. The maximum overall sound pressure level generated upstream of the 

valve reached 156 dB at a nozzle pressure ratio of 2.8. 

4. At the higher valve pressure ratios the upstream spectra are broad 

banded with an apparent tone being generated at the 630 Hz third octave filter 

band. 

5. The overall sound pressure level for this test valve reaches a maximum 

at a mid range valve angular position and falls off on either side of this 

maximum. 

REFERENCE 

1. Huff, Ronald G.: Noise Generated by Flow Through Large Butterfly Valves. 

NASA TM-88911, 1987. 

6 
TABLE I. - POWERED LIFT FACILITY AERODYNAMIC DATA FOR THE 

Read i ng Valve 

number angu 1 ar 

position, 

deg 

487 

488 

48'3 

4'30 

491 

434 

4'35 

496 

497 

498 

501 

502 

503 

504 

505 

508 

509 

510 

511 

512 

515 

516 

517 

518 

5 1 3 

522 

523 

524 

!E1 26 

5213 

530 

531 

532 

533 

c-c ULJ 

30 

30 

30 

30 

SO 

37.5 

37.5 

37.5 

37.5 

37.5 

45 

45 

45 

45 

45 

52.5 

52.5 

52. 5 

52.5 

dL. 5 

60 

60 

60 

60 

60 

75 

75 

75 

75 

75 

90 

90 

90 

90 

90 

E .7 

12-IN. VALVE 

Valve 

pres sure 

ratio 

2.77 

2.36 

1.9 

1.77 

1.37 

2.77 

2.41 

1.99 

1. 70 

1. 36 

2.77 

2. 41 

1.97 

i. 81 

1.38 

2.84 

2.39 

1.98 

1.81 

1. . 4 

2.79 

2.41 

1.99 

1.79 

1.42 

2.79 

2.43 

2 

1. 78 

1.38 

2.82 

2.39 

1.01 

1.81 

1. 41 

NOISE TEST 

Val ve 

upstream 

total 

pressure , psi 

39.27 

33.79 

26. '35 

25.15 

19.47 

35.35 

54.19 

28.22 

25.29 

19.26 

39.39 

34.18 

27.55 

25.64 

19.61 

40.33 

33.88 

20.15 

25. ss 

19.93 

39.58 

34.19 

28. 27 

2s. 3'3 

20. 16 

3'3. bB 

34.47 

26.47 

25.32 

19. CG 

35. '39 

33.55 

28. 53 

25.76 

20.013 

Mass flow 

rate , 

1 b/s 

13.26 

11.13 

11.13 

0. 42 

5.03 

19. 53 

16.83 

13. h3 

11.75 

7. 69 

27.15 

23. 27 

16.41 

10.66 

34.0 

28.64 

23 

20.46 

13. bl 

3'3.13 

32.93 

26.41 

23.03 

15. b8 

42.59 

37.29 

29. 66 

25.42 

16.72 

45.17 

5". 62 

30. "39 

26.73 

17.91 

ia. 3s 

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7 
TABLE 11. - OVERALL SOUND PRESSURE LEVEL DATA 

12-IN. VALVE NOISE TESTS 

Reading Trans 1 Trans 2 Trans 3 Trans 4 

number 

Overall sound pressure level, dB ref. 20 pN/m2 

145. a 

144. 

142. 1 

142.2 

140. G 

149.3 

148.1 

14 5. '3 

146.1 

142. El 

153.5 

1!53 

140.6 

145.4 

155.2 

154. s 

151.7 

150.9 

147. 3 

15r. 9 

154. 3 

1'32.9 

150.3 

147.5 

154.7 

153.5 

149.4 

136. z 

153.8 

151. '7 

143.7 

14'3.4 

146 

148.6 

151. a 

144.3 

144.2 

141.7 

141. G 

140. 1 

149.2 

148. S 

145.7 

145.4 

142 

150.7 

149.7 

148. 5 

144.2 

154.4 

153.7 

151.3 

150.1 

146.4 

155.8 

154.4 

152.3 

143.8 

146. '3 

154.2 

i53. 1 

1%. L 

148.5 

145.9 

151.9 

15G. 7 

14A. 2 

147. 4 

144.4 

148.4 

1G2.2 

:47. 4 

1C4. 5 

1L4. 1 

165.8 

-. 3. ai 

1.7;. a 

1 (. 8 . '7 

IG3. 4 

174. '3 

174.4 

172.5 

171.7 

1G5. 5 

i?Z. 8 

174.4 

173.2 

172. 1 

167.3 

174.2 

1'7 2. e$ 

170. c 

16G. '3 

1 fJ 3 . f; 

164. 4 

1GL':. G 

16i. 4 

12.9. 1 

153.9 

149. 1 

145.7 

144.5 

144.2 

141. 1 

, ...,..~ 

167. LJ 

271;. 9 

175. 1 

173 

172.2 

174.3 

17'3.7 

:70.2 

174. 7 

1-73. 4 

1CG.5 

17'. 5 

17C 

171.3 

171 

16.1 

173.1 

171.8 

163. 2 

lh?. 9 

161.5 

167.6 

165. 6 

114.3 

163.3 

156. !7 

162. ti 

l(t1 

157.7 

156.3 

150.4 

153.7 

147.2 

145.0 

i45.2 

142.1 

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I a 
APPENDIX A 

12-IN. VALVE 1/3 OCTAVE SPECTRAL DATA PLOTS 

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RI-ACK AND WHITE PHOTOGRAPH 
FIGURE 3. ~ PHOTOGRAPH Of 17 IN. VALVE ItST HARDWAHL MUNlFD IN IHk POWLR LlfT FACILITY. 

IIIMI NSION', IN l'll'l IllAfll II I< i 

FIIjIIKE 4, ~ SKt 1L11 01 1,' IN. lilllllKIIY VAIVt NOli~l I !)I lAYOI11 ANI1 

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(>RIGU'JAL PAGE 

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46 
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BLACK ArJD WHITE PHOTOGRAPH 

FIGURE 5. - INTEANAI KlII I tf PRISSIIRt IRANSIillCtR INSlALLAllON SHOWING INFINITE TUBE 

REFERENCE PRFSSIIKt COhi IGIIKAIION. 

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47 
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155 

154 

153 

152 

151 

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2 14.9 

d 147 

* 146 

3 145 

0 

144 

143 

142 

141 

140 

V 

2 

30.0 37.5 45.0 52.5 60.0 75.0 90.0 0.0 

VALVE POSITION. DEG 

(A) TRANSDUCER NUMBER 1. UPSTREM. 

FIGURE 6. - COMPARISON OF OVERALL SOUND PRESSURE LEVEL AT EACH OF THE TRANSDUCER LOCATIONS AS A FUNCTION OF VALVE ANGULAR POSITION AND VALVE PRESSURE 

RATIO. 

156 

155 

154 

153 

152 

L 151 

1 150 0 

149 

w 148 

N 

1 

LL 

w 

-0 

m 147 

146 a 

y 145 0 

144 

143 

142 

141 

140 

0.0 30.0 37.5 45.0 52.5 60.0 75.0 90.0 

VALVE POSITION. DFG 

(B) TRANSDUCER NUMBER 2. UPSTREAM. 

FIGURE 6. - CONTINUED. 

48 
L 

180 

1 7s 

170 

R" 'ldl 

3 l(o 

m 

U 

i 4 

0 

150 

145 

140 

O 

180 

175 

170 

165 

160 

155 

150 

145 

140 

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RAT IO 

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0 2.0 

A 2.4 

X 7.8 

20 40 60 ao 

VALVE POSITION. DEG 

(C) TRANSDUCER NURsER 3. DOWNSTREM. 

FIGURC 6. - CONTINUED. 

1 A 2.4 

X 2.8 

0 20 4Q w 80 

VALVE POSITION, DEG 

(D) TRANSDUCER NUNBER 4. DOWNSTREAM. 

FIGURE 6. - CONCLUDED. 

49 
175 

170 

(v 165 

\ L 

3. 

160 

LL W p: 

2 155 

a 

2 

U 

0 150 

145 

140 

TRANSDUCER 

NUMBER 

1 UPSTREAM 

+ 2 UPSTREAM 

0 3 DOWNSTREIW 

A 4 DOWNSTREAM 

0 20 40 60 

VALVE POSITION. DEG 

(A) VALVE PRESSURE RATIO 1.4. 

FIGURE 7. - COMPARISON OF OVERALL SOUND PRESSURE LEVEL UPSTREAM OF THE VALVE 

TO DOWNSTREAM LEVEL AS A FUNCTION OF VALVE ANGULAR POSITION. 

- 

140 ! I 1 I I I 1 I 1 

20 40 60 80 0 

VALVE POSITION. DEG 

(B) VALVE PRESSURE RATIO 1.8. 

FIGURE 7. - CONTINUED. 

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\,75 - 

bi 

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1 165 - 0 N 

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U m 

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150 - 

145 - 

110 - 174 - 172 - 170 - 168 - 166 - 

? 164 - 162 - 

160 - 

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L 

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5 158 - TRANSDUCER 

156 - NURBER 

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a 152 - + 2 UPSTREAM 

4 0 0 3 DOWNSTREAM 150 - A 4 DOWNSTREAM 148 - 146 - 144 - 142 - 140 I I I I I I I 1 

nz 

U 

2 

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VALVE POS1710N. DEG 

(C) VALVE PRESSURE RATIO 2.0. 

FIGURE 7. - CONTINUED. 

A 4 DOWNSTREAM 

1 UPSTREAM 

+ 2 UPSTREAM 

0 3 DOWNSTREAM 

140 I 1 I I I ! 1 I 

0 20 40 60 80 

VAIVE POSllION, OtG 

(D) VALVE PRESSURE RATIO 2.4. 

FIGURE 7. - CONTINUED. 

51 
150 - 

145 - 

140 

170 

0 1 DOWNSTREAM 

A 4 DOWNSTREAM 

I I I I I 1 I I 

160 

150 

N 

9 140 

R 

= 

130 

U W 

a 

m 120 U 

2 w 110 

s 

+ 2 DOWNSTREAM 

0 3 UPSTREAM 

A 4 UPSTREAM 

X 5 FARFIELD 

v 6 FARFIELD 

80 I , I I I 1 I 1 

0 20 40 KO 80 

VALVE POSITION, DEG 

FIGURE 8. - 54 IN. VALVE. OVERALL SOUND PRESSURE LEVEL UPSTREAM AND DOWNSTREAM 

OF THE VALVE AS A FUNCTION OF VALVE ANGULAR POSITION. 

ORIGINAL PAGE fs 

OF POOR QUAL~TY 

52 
I 

NUMBER 

0 1 UPSTREAM 

+ 2 UPSTREAM 

0 3 DOWNSTREAM 

* 4 DOWNSTREAM 

1rG .---T--r-r--T--7--,--~---r-r--~-~--,T7--r--r--T--T--7--l---r 

18 19 XI 2f 22 .?3 24 25 id L'i' ;'8 %.CJ .XI 31 32 -X3 34 :Xi .%I 37 38 39 f0 

113 OCTAVE BAND NUHBER 

FIGURE 10. - TYPICAL HIGH VALVE PRESSURE RATIO 113 OCTAVE SPECTRA, PRESSURE 

RATIO. 2.8: VALVE POSITION 38 DEG. 

12Gl 

53 
i 

~ 

! 

I 

I 

! 

I 

I 

i 

i 

1. Report No. 

NASA CR- I82232 

NASA National Aeronaulics and Report Documentation Page 

2. Government Accession No. 

17. Key Words (Suggested by Author(s)) 

Acoustics; Valve noise; Butterfly valve; Cockpit noise; 

Aircraft noise 

7. Author(s) 

Ronald G. Huff 

18. Distribution Statement 

Unclassified - Unlimited 

Subject Category 71 

9. Performing Organization Name and Address 

Sverdrup Technology, Inc. 

NASA Lewis Research Center Group 

Cleveland, Ohio 441 35 

2. Sponsoring Agency Name and Address 

National Aeronautics and Space Administration 

Lewis Research Center 

Cleveland, Ohio 44135-3191 

5. Supplementary Notes 

9. Security Classif. (of this report) 

Unclassified 

3. Recipient's Catalog No. 

20. Security Classif. (of this page) 21. No of pages 22. Price' 

Unclassified 54 A03 

5. Report Date 

February 1989 

6. Performing Organization Code 

8. Performing Organization Report No. 

None (E-4556) 

10. Work Unit No. 

505-62-7 1 

11. Contract or Grant No. 

NAS3-25266 

13. Type of Report and Period Covered 

Contractor Report 

Final 

14. Sponsoring Agency Code 

Project Manager, Rudolph E. Grey, Propulsion Systems Division, NASA Lewis Research Center. Ronald G. Huff, 

Ronald G. Huff and Associates, subcontractor to Sverdrup Technology, Inc. (Subcontract Nos. 2717-01-80 and 

2717-85, R.M. Nallasamy, Monitor). 

6. Abstract 

Tests were conducted in the NASA Lewis Research Center's Powered Lift Facility to experimentally evaluate the 

noise generated by a flight weight, 12 in. butterfly valve installed in a proposed vertical takeoff and landing 

thrust vectoring system. Fluctuating pressure measurements were made in the circular duct upstream and downstream of the valve. This data report presents the results of these tests. The maximum overall sound pressure 

level is generated in the duct downstream of the valve and reached a value of 180 dB at a valve pressure ratio of 

2.8. At the higher valve pressure ratios the spectra downstream of the valve is broad banded with its maximum 

at 10oO Hz.