Imperial College London
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Dr Shahid Mughal

Faculty of Natural Sciences, Department of Mathematics

Lecturer in Applied Mathematics
 
 
 
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Contact

 

+44 (0)20 7594 2648s.mughal Website

 
 
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Location

 

734Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@inproceedings{Raposo:2018:10.2514/6.2018-3379,
author = {Raposo, H and Mughal, MS and Ashworth, R},
doi = {10.2514/6.2018-3379},
publisher = {AIAA},
title = {Acoustic receptivity of compressible Tollmien-Schlichting waves with an efficient time-harmonic linearized Navier-Stokes method},
url = {http://dx.doi.org/10.2514/6.2018-3379},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - CPAPER
AB  - The compressible formulation of the time-harmonic linearized Navier-Stokes (LNS) methodfor acoustic receptivity prediction is described.  The efficiency of the proposed approachis rooted in the assumption that the problems of interest only require the time-asymptoticsolution of a few select frequencies. We explore the parabolic nature of the basic flow and of theStokes layer, and we implement an efficient LU decomposition method to obtain the roughness-induced steady perturbation and Tollmien-Schlichting wave.  Before attempting to predictreceptivity amplitudes, the compressible Stokes layer solution based on the linearized unsteadyboundary layer equations is validated in the subsonic regime against an Orr-Sommerfeld-typeequation. Further testing of the model is conducted by reproducing the experiments of King&Breuer in near incompressible conditions.  The results are consistent with the analogueincompressible receptivity model, and reveal excellent agreement with finite-Reynolds numbertheory for two-dimensional instabilities. Qualitative agreement with the experimental resultsfor oblique waves is observed. Differences can be partially explained by the choice of physicalmodel used to determine the N-factors, which in turn are used to extrapolate amplitudes tothe first-branch of stability. Ultimately, a comprehensive comparison with direct-numerical-simulation-based subsonic receptivity amplitudes is conducted, demonstrating the correctnessof the mathematical model and numerical implementation described herein.
AU  - Raposo,H
AU  - Mughal,MS
AU  - Ashworth,R
DO  - 10.2514/6.2018-3379
PB  - AIAA
PY  - 2018///
TI  - Acoustic receptivity of compressible Tollmien-Schlichting waves with an efficient time-harmonic linearized Navier-Stokes method
UR  - http://dx.doi.org/10.2514/6.2018-3379
UR  - https://arc.aiaa.org/doi/abs/10.2514/6.2018-3379
UR  - http://hdl.handle.net/10044/1/62211
ER  -
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