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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: aa406@cam.ac.uk
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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

REFERENCES

Agarwal, A., Morris, P. J. & Mani, R. 2004 Calculation of sound propagation in nonuniform flows: suppression of instability waves. AIAA J. 42 (1), 80–88.CrossRefGoogle Scholar
Cabana, M., Fortuné, V. & Jordan, P. 2008 Identifying the radiating core of Lighthill's source term. Theor. Comput. Fluid Dyn. 22 (2), 87–106.CrossRefGoogle Scholar
Crighton, D. G. 1975 Basic principles of aerodynamic noise generation. Prog. Aerosp. Sci. 16, 31–96.CrossRefGoogle Scholar
Dowling, A. P. & Ffowcs Williams, J. E. 1983 Sound and Sources of Sound. Ellis Horwood.Google Scholar
Freund, J. B. 2001 Noise sources in a low-Reynolds-number turbulent jet at Mach 0.9. J. Fluid Mech. 438, 277–305.CrossRefGoogle Scholar
Goldstein, M. E. 1976 Aeroacoustics. McGraw-Hill International.Google Scholar
Goldstein, M. E. 2003 A generalized acoustic analogy. J. Fluid Mech. 488, 315–33.CrossRefGoogle Scholar
Goldstein, M. E. 2005 On identifying the true sources of aerodynamic sound. J. Fluid Mech. 526, 337–347.CrossRefGoogle Scholar
Goldstein, M. E. 2009 A theoretical basis for identifying the sound sources in a turbulent flow. Intl J. Aeroacoust. 8 (4), 283–300.CrossRefGoogle Scholar
Guizar-Sicairos, M. & Gutiérrez-Vega, J. C. 2004 Computation of quasi-discrete Hankel transforms of integer order for propagating optical wave fields. J. Opt. Soc. Am. A 21 (1), 53–58.CrossRefGoogle ScholarPubMed
Lilley, G. M. 1974 On the noise from jets. In AGARD Conference Proceedings No. 131 on Noise Mechanisms, Brussels, Belgium, pp. 13–21.Google Scholar
Shin, K. & Hammond, J. 2008 Fundamentals of Signal Processing for Sound and Vibration Engineers. Wiley.Google Scholar
Sinayoko, S. & Agarwal, A. 2010 a Flow filtering and the physical sources of aerodynamic sound. In IUTAM Symposium on Computational Aeroacoustics for Aircraft Noise Prediction, Southampton, UK.Google Scholar
Sinayoko, S. & Agarwal, A. 2010 b On computing the physical sources of jet noise. AIAA Paper 2010-3962. 16th AIAA/CEAS Aeroacoustics Conference, Stockholm, Sweden.Google Scholar
Stromberg, J. L., McLaughlin, D. K. & Troutt, T. R. 1980 Flow field and acoustic properties of a Mach number 0.9 jet at a low Reynolds number. J. Sound Vib. 72 (2), 159–176.CrossRefGoogle Scholar
Suponitsky, V. & Sandham, N. D. 2009 Nonlinear mechanisms of sound radiation in a subsonic flow. AIAA Paper 2009-3317. 15th AIAA/CEAS Aeroacoustics Conference, Miami, Florida, USA.Google Scholar
Tinney, C. E. & Jordan, P. 2008 The near pressure field of co-axial subsonic jets. J. Fluid Mech. 611, 175–204.CrossRefGoogle Scholar