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Flow decomposition and aerodynamic sound generation

Published online by Cambridge University Press:  03 December 2010

SAMUEL SINAYOKO ,
A. AGARWAL  and
Z. HU
SAMUEL SINAYOKO
Affiliation:
Institute of Sound and Vibration Research, University of Southampton, Southampton S017 1BJ, UK
A. AGARWAL*
Affiliation:
Institute of Sound and Vibration Research, University of Southampton, Southampton S017 1BJ, UK
Z. HU
Affiliation:
School of Engineering Sciences, University of Southampton, Southampton S017 1BJ, UK
*
†Present address: Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ. Email address for correspondence: [email protected]
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Abstract

An approximate decomposition of fluid-flow variables satisfying unbounded compressible Navier–Stokes equations into acoustically radiating and non-radiating components leads to well-defined source terms that can be identified as the physical sources of aerodynamic noise. We show that, by filtering the flow field by means of a linear convolution filter, it is possible to decompose the flow into non-radiating and radiating components. This is demonstrated on two different flows: one satisfying the linearised Euler equations and the other the Navier–Stokes equations. In the latter case, the corresponding sound sources are computed. They are found to be more physical than those computed through classical acoustic analogies in which the flow field is decomposed into a steady mean and fluctuating component.

JFM classification

Acoustics: Aeroacoustics Acoustics: Jet noise
Type
Papers
Information
Journal of Fluid Mechanics , Volume 668 , 10 February 2011 , pp. 335 - 350
Copyright
Copyright © Cambridge University Press 2010

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References

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