Mach Number Effects on Jet Noise Sources and Radiation to Shallow Angles

AIAA Journal ◽  
2006 ◽  
Vol 44 (8) ◽  
pp. 1915-1918 ◽  
Author(s):  
James I. Hileman ◽  
Mo Samimy
Keyword(s):  
2012 ◽  
Vol 232 ◽  
pp. 213-217
Author(s):  
Jia Ming Li ◽  
Chun Bo Hu ◽  
Jun Hua Bai

In order to investigate the characteristic of the supersonic jet screech tones, an experimental bench of the supersonic jet was designed and a free field noise signal acquisition system was established. Effects of the nozzle size and jet Mach number on jet noise sound field distribution was analyzed, through the result comparison of supersonic jet noise experimental measurement. Results indicate that the field distribution of supersonic jet screech tones is characterized with very strong directivity. Peak value of the screech tones decrease and occurrence frequency of the screech tones increase with the decreasing jet exit Mach number; occurrence frequency of the screech tones decrease with the increasing nozzle size, but the peak value change very less. The experimental measurement of supersonic jet noise provides mechanism research of sound production with data supports and references; and also provides the numerical modeling of supersonic jet noise with validation criteria.


Author(s):  
Gary G. Podboy

An experiment was conducted to investigate the effect that a planar surface located near a jet flow has on the noise radiated to the far-field. Two different configurations were tested: 1) a shielding configuration in which the surface was located between the jet and the far-field microphones, and 2) a reflecting configuration in which the surface was mounted on the opposite side of the jet, and thus the jet noise was free to reflect off the surface toward the microphones. Both conventional far-field microphone and phased array noise source localization measurements were obtained. This paper discusses phased array results, while a companion paper discusses far-field results. The phased array data show that the axial distribution of noise sources in a jet can vary greatly depending on the jet operating condition and suggests that it would first be necessary to know or be able to predict this distribution in order to be able to predict the amount of noise reduction to expect from a given shielding configuration. The data obtained on both subsonic and supersonic jets show that the noise sources associated with a given frequency of noise tend to move downstream, and therefore, would become more difficult to shield, as jet Mach number increases. The noise source localization data obtained on cold, shock-containing jets suggests that the constructive interference of sound waves that produces noise at a given frequency within a broadband shock noise hump comes primarily from a small number of shocks, rather than from all the shocks at the same time. The reflecting configuration data illustrates that the law of reflection must be satisfied in order for jet noise to reflect off of a surface to an observer, and depending on the relative locations of the jet, the surface, and the observer, only some of the jet noise sources may satisfy this requirement.


2021 ◽  
Author(s):  
Hasan Kamliya Jawahar ◽  
Stefano Meloni ◽  
Roberto Camussi ◽  
Mahdi Azarpeyvand

AIAA Journal ◽  
1978 ◽  
Vol 16 (11) ◽  
pp. 1121-1122
Author(s):  
Leon Avezard ◽  
Claude Dahan ◽  
Georges Elias ◽  
Annie Lelarge ◽  
Jean Maulard ◽  
...  

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