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Published May 2005 | Published
Conference Paper Open

Modeling Jet Noise from Organized Structures Using Near-Field Hydrodynamic Pressure

Abstract

A wave-packet ansatz is used to model noise generation by organized, large-scale structures. The spectrum of the acoustic field is expressed in terms of two-point space-time correlations of hydrodynamic pressure on a conical surface surrounding the jet plume. The surface is sufficiently near the turbulent flow region to be dominated by hydrodynamic disturbances, yet sufficiently far that the wave equation can be used to project the nearfield pressure to the acoustic field. In the present study, a 78-microphone array was used to measure hydrodynamic pressure on the conical surface at a variety of acoustic Mach numbers and temperature ratios. At each jet cross section, 6 microphones are staggered in the azimuthal direction allowing resolution of pressure up to azimuthal mode number m = 2. We compare recent jet noise measurements using an 80-microphone conical mid-field array with those derived from the near-field hydrodynamic array data, showing reasonably good predictions. Source model parameters are identified for various jet temperature ratios. Results show that changes in jet noise directivity with heating can be attributed to contraction of the wave-packet scale.

Additional Information

© 2005 by the author(s). Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Published Online: 11 Nov 2012. The authors are indebted to Drs. J. Bridges and S.-S. Lee for generously sharing their data and for fruitful discussions. TC and TS gratefully acknowledge the support of a grant from the Aeroacoustics Research Consortium (AARC) of the Ohio Aerospace Institute.

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Created:
August 19, 2023
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October 20, 2023