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Predictions of Supersonic Jet Mixing and Shock-Associated Noise Compared with Measured Far-Field Data

Author : National Aeronautics and Space Administration (NASA)

Publisher : Createspace Independent Publishing Platform

Page : 78 pages

File Size : 10,49 MB

Release : 2018-05-22

Category :

ISBN : 9781719493345

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Book Description

Codes for predicting supersonic jet mixing and broadband shock-associated noise were assessed using a database containing noise measurements of a jet issuing from a convergent nozzle. Two types of codes were used to make predictions. Fast running codes containing empirical models were used to compute both the mixing noise component and the shock-associated noise component of the jet noise spectrum. One Reynolds-averaged, Navier-Stokes-based code was used to compute only the shock-associated noise. To enable the comparisons of the predicted component spectra with data, the measured total jet noise spectra were separated into mixing noise and shock-associated noise components. Comparisons were made for 1/3-octave spectra and some power spectral densities using data from jets operating at 24 conditions covering essentially 6 fully expanded Mach numbers with 4 total temperature ratios. Dahl, Milo D. Glenn Research Center JET MIXING FLOW; JET AIRCRAFT NOISE; SUPERSONIC JET FLOW; AERODYNAMIC NOISE; NOISE MEASUREMENT; NOISE SPECTRA; FLUID JETS; MACH NUMBER; PREDICTIONS; SHOCK WAVES; TEMPERATURE RATIO

















Aeroacoustics of Flight Vehicles: Theory and Practice. Volume 1: Noise Sources

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Publisher :

Page : 616 pages

File Size : 30,10 MB

Release : 1991

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ISBN :

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Book Description

The field of aeroacoustics has matured dramatically in the past two decades. Researchers have gained significant theoretical and experimental understanding of the noise generated by aircraft power plants and their components. In addition, airframe noise and interior noise have been investigated extensively. The physical understanding obtained from these efforts has resulted in the development of hardware capable of reducing community noise and of meeting strict noise certification requirements. Reductions in overall sound pressure level of 20 to 30 dB have been obtained for some types of power plants, while in the same period their installed power has increased significantly. Current quiet flight vehicle designs are based on information reported in a multitude of journals, conference proceeding, research reports, and specialized books. Each of these scientific publications represents only incremental steps in the evolution of our present understanding of the various aeroacoustic noise generation and propagation mechanisms and procedures for noise control.