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Effect of base-flow variation in noise amplifiers: the flat-plate boundary layer

Published online by Cambridge University Press:  14 October 2011

Luca Brandt*
Affiliation:
Linné Flow Centre, KTH Mechanics, S-100 44 Stockholm, Sweden
Denis Sipp
Affiliation:
ONERA/DAFE, 8 rue des Vertugadins, 92190 Meudon, France
Jan O. Pralits
Affiliation:
DIMEC, University of Salerno, Via Ponte don Melillo, 84084 Fisciano (SA), Italy
Olivier Marquet
Affiliation:
ONERA/DAFE, 8 rue des Vertugadins, 92190 Meudon, France
*
Email address for correspondence: [email protected]

Abstract

Non-modal analysis determines the potential for energy amplification in stable flows. The latter is quantified in the frequency domain by the singular values of the resolvent operator. The present work extends previous analysis on the effect of base-flow modifications on flow stability by considering the sensitivity of the flow non-modal behaviour. Using a variational technique, we derive an analytical expression for the gradient of a singular value with respect to base-flow modifications and show how it depends on the singular vectors of the resolvent operator, also denoted the optimal forcing and optimal response of the flow. As an application, we examine zero-pressure-gradient boundary layers where the different instability mechanisms of wall-bounded shear flows are all at work. The effect of the component-type non-normality of the linearized Navier–Stokes operator, which concentrates the optimal forcing and response on different components, is first studied in the case of a parallel boundary layer. The effect of the convective-type non-normality of the linearized Navier–Stokes operator, which separates the spatial support of the structures of the optimal forcing and response, is studied in the case of a spatially evolving boundary layer. The results clearly indicate that base-flow modifications have a strong impact on the Tollmien–Schlichting (TS) instability mechanism whereas the amplification of streamwise streaks is a very robust process. This is explained by simply examining the expression for the gradient of the resolvent norm. It is shown that the sensitive region of the lift-up (LU) instability spreads out all over the flat plate and even upstream of it, whereas it is reduced to the region between branch I and branch II for the TS waves.

Type
Papers
Copyright
Copyright © Cambridge University Press 2011

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References

1. Åkervik, E., Ehrenstein, U., Gallaire, F. G. & Henningson, D. S. 2008 Two-dimensional global stability measures of the flat plate boundary-layer flow. Eur. J. Mech. (B/Fluids) 27, 501513.CrossRefGoogle Scholar
2. Alizard, F., Cherubini, S. & Robinet, J.-C. 2009 Sensitivity and optimal forcing response in separated boundary layer flows. Phys. Fluids 21, 064108.CrossRefGoogle Scholar
3. Barkley, D., Blackburn, H. M. & Sherwin, S. J. 2008 Direct optimal growth analysis for time steppers. Intl J. Numer. Meth. Fluids 57, 14351458.CrossRefGoogle Scholar
4. Blackburn, H. M., Barkley, D. & Sherwin, S. J. 2008 Convective instability and transient growth in flow over a backward-facing step. J. Fluid Mech. 608, 271304.CrossRefGoogle Scholar
5. Bottaro, A., Corbett, P. & Luchini, P. 2003 The effect of base flow variationon flow stability. J. Fluid Mech. 476, 293302.CrossRefGoogle Scholar
6. Brandt, L., Schlatter, P. & Henningson, D. S. 2004 Transition in boundary layers subject to free stream turbulence. J. Fluid Mech. 517, 167198.CrossRefGoogle Scholar
7. Butler, K. M. & Farrell, B. F. 1992 Three-dimensional optimal perturbations in viscous shear flow. Phys. Fluids A 4, 16371650.CrossRefGoogle Scholar
8. Cathalifaud, P. & Luchini, P. 2000 Algebraic growth in boundary layers: optimal control by blowing and suction at the wall. Eur. J. Mech. (B/Fluids) 19, 469490.CrossRefGoogle Scholar
9. Chomaz, J.-M. 2005 Global instabilities in spatially developing flows: non-normality and nonlinearity. Annu. Rev. Fluid Mech. 37, 357392.CrossRefGoogle Scholar
10. Chomaz, J. M., Huerre, P. & Redekopp, L. G. 1991 A frequency selection criterion in spatially developing flows. Stud. Appl. Maths 84, 119144.CrossRefGoogle Scholar
11. Corbett, P. & Bottaro, A. 2000 Optimal perturbations for boundary layers subject to stream-wise pressure gradient. Phys. Fluids 12 (1), 120130.CrossRefGoogle Scholar
12. Farrell, B. F. 1988 Optimal excitation of perturbations in viscous shear flow. Phys. Fluids 31, 20932102.CrossRefGoogle Scholar
13. Farrell, B. F. & Ioannou, P. J. 1996 Generalized stability theory. Part I: autonomous operators. Part II: nonautonomous operators. J. Atmos. Sci. 53, 20252053.2.0.CO;2>CrossRefGoogle Scholar
14. Gavarini, I., Bottaro, A. & Nieuwstadt, F. T. M. 2004 The initial stage of transition in pipe flow: role of optimal base-flow distortions. J. Fluid Mech. 517, 131165.CrossRefGoogle Scholar
15. Giannetti, F. & Luchini, P. 2007 Structtural sensitivity of the first instability of the cylinder wake. J. Fluid Mech. 581, 167197.CrossRefGoogle Scholar
16. Grosch, C. E. & Salwen, H. 1978 The continuous spectrum of the Orr–Sommerfeld equation. Part 1. The spectrum and the eigenfunctions. J. Fluid Mech. 87, 3354.CrossRefGoogle Scholar
17. Huerre, P. & Rossi, M. 1998 Hydrodynamic instabilities in open flows. In Hydrodynamic and Nonlinear Instabilities (ed. Godrèche, C. & Manneville, P. ). pp. 81294. Cambridge University Press.CrossRefGoogle Scholar
18. Jovanovic, M. R. & Bamieh, B. 2005 Componentwise energy amplification in channel flows. J. Fluid Mech. 534, 145183.CrossRefGoogle Scholar
19. Landahl, M. T. 1980 A note on an algebraic instability of inviscid parallel shear flows. J. Fluid Mech. 98, 243251.CrossRefGoogle Scholar
20. Marquet, O., Lombardi, M., Chomaz, J. -M., Sipp, D. & Jacquin, L. 2009 Direct and adjoint global modes of a recirculation bubble: lift-up and convective non-normalities. J. Fluid Mech. 622, 121.CrossRefGoogle Scholar
21. Marquet, O., Sipp, D. & Jacquin, L. 2008 Sensitivity analysis and passive control of cylinder flow. J. Fluid Mech. 615, 221252.CrossRefGoogle Scholar
22. Monokrousos, A., Åkervik, E., Brandt, L. & Henningson, D. S. 2010 Global three-dimensional optimal disturbances in the Blasius boundary-layer flow using time steppers. J. Fluid Mech. 650, 181214.CrossRefGoogle Scholar
23. Pralits, J. O., Airiau, C., Hanifi, A. & Henningson, D. 2000 Sensitivity analysis using adjoint parabolized stability equations for compressible flows. Flow Turbul. Combust. 65, 321346.CrossRefGoogle Scholar
24. Pralits, J. O., Brandt, L. & Giannetti, F. 2010 Instability and sensitivity of the ow around a rotating circular cylinder. J. Fluid Mech. 650, 513536.CrossRefGoogle Scholar
25. Reddy, S. C. & Henningson, D. S. 1993 Energy growth in viscous channel flows. J. Fluid Mech. 252, 209238.CrossRefGoogle Scholar
26. Schmid, P. J. & Henningson, D. S. 2001 Stability and Transition in Shear Flows. Springer.CrossRefGoogle Scholar
27. Schrader, L.-U., Brandt, L., Mavriplis, C. & Henningson, D. S. 2010 Receptivity to free stream vorticity of flow past a flat plate with elliptic leading edge. J. Fluid Mech. 653, 245271.CrossRefGoogle Scholar
28. Sipp, D., Marquet, O., Meliga, P. & Barbagallo, A. 2010 Dynamics and control of global instabilities in open flows: a linearized approach. Appl. Mech. Rev. 63, 030801.CrossRefGoogle Scholar
29. Weideman, J. A. C. & Reddy, S. C. 2000 A matlab differentiation matrix suite. ACM Trans. Math. Softw. 26 (4), 465519.CrossRefGoogle Scholar
30. Zaki, T. A. & Durbin, P. A. 2005 Mode interaction and the bypass route to transition. J. Fluid Mech. 531, 85111.CrossRefGoogle Scholar
31. Zuccher, S., Luchini, P. & Bottaro, A. 2004 Algebraic growth in a Blasius boundary layer: optimal and robust control by mean suction in the nonlinear regime. J. Fluid Mech. 513, 135160.CrossRefGoogle Scholar