The radiation of sound from a perfectly expanded Mach 2.5 cold supersonic jet of 25.4 mm exit diameter flowing through a partially open rigid-walled duct with an upstream J-deflector has been experimentally studied. In the experiments, the nozzle is mounted vertically, with the nozzle exit plane at a height of 73 jet diameters above ground level. Relative to the nozzle exit plane (NEP), the location of the duct inlet is varied at 10, 5, and –1 jet diameters. Far-field sound pressure levels were obtained at 54 jet diameters above ground with the aid of acoustic sensors equally spaced around a circular arc of radius equal to 80 jet diameters from the jet axis. Data on the jet acoustic field for the partially open duct were obtained and compared with those with a free jet and with a closed duct. The results suggest that for the partially open duct the overall sound pressure level (OASPL) decreases as the distance between the NEP and the duct inlet plane decreases, while the opposite trend is observed for the closed duct. It is also concluded that the observed peak frequency in the partially open duct increases above the free jet value as the angle from the duct axis is increased, and as the duct inlet plane becomes closer to the NEP.

Issue Section:
Technical Briefs
Keywords:
acoustic field, acoustic intensity, acoustic noise, aeroacoustics, ducts, jets, nozzles, Sound emission, jet noise, ducted exhaust
Topics:
Ducts, Nozzles, Exhaust systems, Noise (Sound), Acoustics, Sound pressure, Sound

References

1.
Kandula
,
M.
, 2008,
“On the Scaling Laws and Similarity Spectra for Jet Noise in Subsonic and Supersonic Flow,”
Int. J. Acoust. Vib.
,
13
(
1
), pp.
3
–
16
.
2.
Kandula
,
M.
, 2007,
“Near Field Acoustics of Clustered Rocket Engines,”
J. Sound Vib.
,
309
, pp.
852
–
857
.
Crossref
Search ADS
 
3.
Henderson
,
B.
, 2010,
“Fifty Years of Fluidic Injection for Jet Noise Reduction,”
Int. J. Aeroacoust.
,
9
(
1&2
), pp.
91
–
122
.
4.
Norum
,
T. D.
,
“Reductions in Multi-Component Jet Noise by Water Injection,”
AIAA Paper No. 98-2204, 1998.
5.
Krothapalli
,
A.
,
Venkatakrishnan
,
L.
,
Lourenco
,
L.
, and
Greska
,
B.
, 2003,
“Turbulence and Noise Suppression of a High-Speed Jet by Water Injection,”
J. Fluid Mech.
,
491
, pp.
131
–
159
.
Crossref
Search ADS
 
6.
Kandula
,
M.
, 2008,
“Prediction of Turbulent Jet Mixing Noise Reduction by Water Injection,”
AIAA J.
,
46
(
11
), pp.
2714
–
2722
.
Crossref
Search ADS
 
7.
Kandula
,
M.
, 2009,
“Broadband Shock Noise Reduction in Turbulent Jets by Water Injection,”
Appl. Acoust.
,
70
, pp.
1009
–
1014
.
Crossref
Search ADS
 
8.
Kandula
,
M.
, 2008,
“Spectral Attenuation of Sound in Dilute Suspensions With Nonlinear Particle Relaxation,”
J. Acoust. Soc. Am.
,
124
, pp.
EL
-284–
EL290
.
9.
Eversman
,
W.
, and
Roy
,
I. D.
,
“Ducted Fan Acoustic Radiation Including the Effects of Nonuniform Mean Flow and Acoustic Treatment,”
AIAA Paper No. 93-4424, 1993.
10.
Ozyoruk
,
Y.
, and
Long
,
L.
, 1996,
“Computation of Sound Radiated from Engine Inlets,”
AIAA J.
,
34
, pp.
894
–
901
.
Crossref
Search ADS
 
11.
Kandula
,
M.
, and
Vu
,
B.
, 2003,
“Scale Model Experiments on Sound Propagation From a Mach 2.5 Cold Nitrogen Jet Flowing Through a Rigid-Walled Duct With a J-Deflector,”
NASA Report No. TM-2003-211186, Kennedy Space Center.
12.
Vu
,
B.
, and
Kandula
,
M.
, 2003,
“Noise Mitigation of Ducted Supersonic Jets for Launch Exhaust Management Systems,”
JANNAF 27th Plume Technology Subcommittee Meeting
,
NASA Stennis Space Center
,
Bay St. Louis, Mississippi, May 5–9, 2003.
13.
Kandula
,
M.
, 2006,
“An Experimental And Numerical Study of Sound Propagation From a Supersonic Jet Passing Through a Rigid-Walled Duct with a J-Deflector,”
Int. J. Acoust. Vib.
11
(
3
), pp.
125
–
131
.
14.
Shapiro
,
A. H.
, 1953,
The Dynamics and Thermodynamics of Compressible Fluid Flow
,
Wiley
,
New York
, Vol.
1
.
15.
Eldred
,
K. M.
, 1971,
“Acoustic Loads Generated by the Rocket Propulsion System,”
NASA Report No. SP-8072.
16.
Bishop
,
K. A.
,
Ffowcs Williams
,
J. E.
, and
Smith
,
W.
, 1971,
“On the Noise Source of the Unsuppressed High-Speed Jet,”
J. Fluid Mech.
,
50
, pp.
21
–
31
.
Crossref
Search ADS
 
17.
MacGregor
,
G. R.
 and
Simcox
,
L. D.
,
“The Location of Acoustic Sources in Jet Flow by Means of the “Wall Isolation” Technique,”
AIAA Paper No. 1973-1041, 1973.
18.
Krothapalli
,
A.
,
Rajkuperan
,
E.
,
Alvi
,
F.
, and
Lourenco
,
L.
, 1999,
“Flowfield and Noise Characteristics of a Supersonic Impinging Jet,”
J. Fluid Mech.
,
392
, pp.
155
–
181
.
Crossref
Search ADS
 
19.
Lamont
,
P. J.
, and
Hunt
,
B. L.
, 1980,
“The Impingement of Underexpanded Axisymmetric Jets on Perpendicular and Inclined Plates,”
J. Fluid Mech.
,
100
, pp.
471
–
511
.
Crossref
Search ADS
 
20.
Von Glahn
,
U.
,
Goodykoontz
,
J.
, and
Wagner
,
J.
, 1973,
“Nozzle Geometry And Forward Velocity Effects on Noise From CTOL Engine-Over-The Wing Concept,”
NASA Report No. TM-X-71453.
21.
Fink
,
M. R.
,
“Scrubbing noise of externally blown flaps,”
AIAA Paper No. 1975-469, 1975.
22.
Goebel
,
S. G.
, and
Dutton
,
J. C.
, 1991,
“Experimental Study of Compressible Turbulent Mixing Layers,”
AIAA J.
,
29
, pp.
538
–
546
.
Crossref
Search ADS
 
23.
Kandula
,
M.
, and
Wilcox
,
D. C. W.
,
“An Examination of k − ω Turbulence Model for Boundary Layers, Mixing Layers and Separated Flows,”
AIAA Paper No. 95-2317, 1995.
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