Imperial College London
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DrPrasunRay

Faculty of Natural Sciences, Department of Mathematics

Senior Teaching Fellow in Applied Mathematics
 
 
 
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p.ray

 
 
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Location

 

6M20Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{RAY:2007:10.1017/s0022112007007306,
author = {RAY, PK and LELE, SK},
doi = {10.1017/s0022112007007306},
journal = {Journal of Fluid Mechanics},
pages = {173--215},
title = {Sound generated by instability wave/shock-cell interaction in supersonic jets},
url = {http://dx.doi.org/10.1017/s0022112007007306},
volume = {587},
year = {2007}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - <jats:p>Broadband shock-associated noise is an important component of the overall noise generated by modern airplanes. In this study, sound generated by the weakly nonlinear interaction between linear instability waves and the shock-cell structure in supersonic jets is investigated numerically in order to gain insight into the broadband shock-noise problem. The model formulation decomposes the overall flow into a mean flow, linear instability waves, the shock-cell structure and shock-noise. The mean flow is obtained by solving RANSequations with a <jats:italic>k</jats:italic>-ε model. Locally parallel stability equations are solved for the shock structure, and linear parabolized stability equations are solved for the instability waves. Then, source terms representing the instability wave/shock-cell interaction are assembled and the inhomogeneous linearized Euler equations are solved for the shock-noise.Three cases are considered, a cold under-expanded <jats:italic>M<jats:sub>j</jats:sub></jats:italic> = 1.22 jet, a hot under-expanded <jats:italic>M<jats:sub>j</jats:sub></jats:italic> = 1.22 jet, and a cold over-expanded <jats:italic>M<jats:sub>j</jats:sub></jats:italic> = 1.36 jet.</jats:p><jats:p>Shock-noise computations are used to identify and understand significant trends in peak sound amplitudes and radiation angles. The peak sound radiation angles are explained well with the Mach wave model of Tam & Tanna <jats:italic>J. Sound Vib</jats:italic>. Vol. 81, 1982, p. 337). The observed reduction of peak sound amplitudes with frequency correlates well with the corresponding reduction of instability wave growth with frequency. However, in order to account for variation of sound amplitude for different azimuthal modes, the radial structure of the instability waves must be considered in additionto streamwise growth. The effect of heating on
AU  - RAY,PK
AU  - LELE,SK
DO  - 10.1017/s0022112007007306
EP  - 215
PY  - 2007///
SN  - 0022-1120
SP  - 173
TI  - Sound generated by instability wave/shock-cell interaction in supersonic jets
T2  - Journal of Fluid Mechanics
UR  - http://dx.doi.org/10.1017/s0022112007007306
VL  - 587
ER  -
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