Phased-array measurements of full-scale military jet noise

Author(s):  
Blaine M. Harker ◽  
Kent L. Gee ◽  
Tracianne B. Neilsen ◽  
Alan T. Wall ◽  
Michael M. James
2019 ◽  
Vol 146 (1) ◽  
pp. 665-680
Author(s):  
Blaine M. Harker ◽  
Kent L. Gee ◽  
Tracianne B. Neilsen ◽  
Alan T. Wall ◽  
Michael M. James

Author(s):  
Justin Lan ◽  
John Premo ◽  
Gabriel Zlavog ◽  
Cyrille Breard ◽  
Bryan Callender ◽  
...  

2021 ◽  
Author(s):  
Henri A. Siller ◽  
Timo Schumacher ◽  
Wolfram Hage

Author(s):  
Gary G. Podboy ◽  
James E. Bridges ◽  
Brenda S. Henderson

A 48-microphone planar phased array system was used to acquire jet noise source localization data on both a full-scale F404-GE-F400 engine and on a 1/4th scale model of a F400 series nozzle. The full-scale engine test data show the location of the dominant noise sources in the jet plume as a function of frequency for the engine in both baseline (no chevron) and chevron configurations. Data are presented for the engine operating both with and without afterburners. Based on lessons learned during this test, a set of recommendations are provided regarding how the phased array measurement system could be modified in order to obtain more useful acoustic source localization data on high-performance military engines in the future. The data obtained on the 1/4th scale F400 series nozzle provide useful insights regarding the full-scale engine jet noise source mechanisms, and document some of the differences associated with testing at model-scale versus full-scale.


2018 ◽  
Vol 144 (3) ◽  
pp. 1356-1367 ◽  
Author(s):  
Alan T. Wall ◽  
Kent L. Gee ◽  
Kevin M. Leete ◽  
Tracianne B. Neilsen ◽  
Trevor A. Stout ◽  
...  

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.


2015 ◽  
Vol 138 (3) ◽  
pp. 1916-1916
Author(s):  
Trevor A. Stout ◽  
Kent L. Gee ◽  
Tracianne B. Neilsen ◽  
Alan T. Wall ◽  
Michael M. James

2003 ◽  
Vol 2 (3) ◽  
pp. 371-412 ◽  
Author(s):  
K. K. Ahuja

The main objective of this paper is to provide guidelines for designing and calibrating a high quality, static, jet-noise research facility and making high-quality jet noise measurements. Particular emphasis is placed on methodology for determining if internal noise is dominant in the jet noise spectrum. A section of this document is devoted to clarifying the terminology associated with microphone frequency response corrections and providing a step-wise description of other corrections that must be applied to the measured raw spectra before the jet noise data can be considered accurate and ready for use for extrapolation to full-scale jet engine noise.


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