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Modal description of internal optimal streaks

Published online by Cambridge University Press:  10 May 2009

MARÍA HIGUERA*
Affiliation:
E. T. S. Ingenieros Aeronáuticos, Universidad Politécnica de Madrid, Plaza Cardenal Cisneros, 3, 28040 Madrid, Spain
JOSÉ M. VEGA
Affiliation:
E. T. S. Ingenieros Aeronáuticos, Universidad Politécnica de Madrid, Plaza Cardenal Cisneros, 3, 28040 Madrid, Spain
*
Email address for correspondence: maria.higuera@upm.es

Abstract

This paper deals with the definition and description of optimal streaky (S) perturbations in a Blasius boundary layer. First, the asymptotic behaviours of S-perturbations near the free stream and the leading edge are studied to conclude that the former is slaved to the solution inside the boundary layer. Based on these results, a quite precise numerical scheme is constructed that allows concluding that S-perturbations produced inside the boundary layer, near the leading edge, can be defined in terms of just one streamwise-evolving solution of the linearized equations, associated with the first eigenmode of an eigenvalue problem first formulated by Luchini (J. Fluid Mech., vol. 327, 1996, p. 101). Such solution may be seen as an internal unstable streaky mode of the boundary layer, similar to eigenmodes of linearized stability problems. The remaining modes decay streamwise. Thus, the definition of streaks in terms of an optimization problem that is used nowadays is not necessary.

Type
Papers
Copyright
Copyright © Cambridge University Press 2009

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References

REFERENCES

Andersson, P., Berggren, M. & Henningson, D. S. 1999 Optimal disturbances and bypass transition in boundary layers. Phys. Fluids 11, 134150.CrossRefGoogle Scholar
Bagget, J. S. & Threfethen, L. N. 1997 Low dimensional models of subcritical transition to turbulence. Phys. Fluids 9, 10431053.CrossRefGoogle Scholar
Cossu, C. & Brandt, L. 2002 Stabilization of Tollmien–Schlichting waves by finite amplitude optimal streaks in a Blasius boundary layer. Phys. Fluids 14, L.57L.60.CrossRefGoogle Scholar
Crow, S. C. 1966 The spanwise perturbations of two dimensional boundary layers. J. Fluid Mech. 24 153164.CrossRefGoogle Scholar
Ellingsen, T. & Palm, E. 1975 Stability of linear flow. Phys. Fluids 18, 487488.CrossRefGoogle Scholar
Fransson, J. H. M., Brandt, L., Talamelli, A. & Cossu, C. 2004 Experimental and theoretical investigation of the nonmodal growth of steady streaks in a flat plate boundary layer. Phys. Fluids 16, 36273638.Google Scholar
Fransson, J. H. M., Talamelli, A., Brandt, L. & Cossu, C. 2006 Delaying transition to turbulence by a passive mechanism. Phys. Rev. Lett. 96, 064501-1-4.CrossRefGoogle ScholarPubMed
Hultgren, L. S. & Gustavsson, L. H. 1981 Algebraic growth of disturbances in a laminar boundary layer. Phys. Fluids 24, 10001004.CrossRefGoogle Scholar
Klebanoff, P. S., Tidstrom, K. D., & Sargent, L. M. 1962 The three-dimensional nature of boundary layer instability. J. Fluid Mech. 12, 134.CrossRefGoogle Scholar
Lambert, J. D. 2000 Numerical Methods for Ordinary Differential Systems. John Wiley & Sons.Google Scholar
Landahl, M. T. 1980 A note on the algebraic instability of inviscid parallel shear flows. J. Fluid Mech. 98, 243251.CrossRefGoogle Scholar
Leib, S. J., Wundrow, D. W. & Goldstein, M. E. 1999 Effect of free-stream turbulence and other vortical disturbances on laminar boundary layer J. Fluid Mech. 380, 169203.CrossRefGoogle Scholar
Libby, P. A. & Fox, H. 1964 Some perturbation solutions in laminar boundary-layer theory. J. Fluid Mech. 17, 433449.Google Scholar
Luchini, P. 1996 Reynolds-number-independent instability of boundary layer over a flat surface. J. Fluid Mech. 327, 101115.CrossRefGoogle Scholar
Luchini, P 2000 Reynolds-number-independent instability of boundary layer over a flat surface: optimal perturbations. J. Fluid Mech. 404, 289309.CrossRefGoogle Scholar
Morkovin, M. V. 1984 Bypass transition to turbulence and research desiderata. In Laminar-Turbulent Transition (ed. Arnal, D. & Michel, R.), pp. 329. Springer.Google Scholar
Morkovin, M. V. & Reshotko, E. 1990 Dialog on progress and issues in stability and transition research. In Transition in Turbines, pp. 161204. NASA Conf. Pub. 2386.Google Scholar
Schmid, P. J. 2007 Nonmodal stability theory. Annu. Rev. Fluid Mech. 39, 129162.CrossRefGoogle Scholar
Stewartson, K. 1957 On asymptotic expansion in the theory of laminar boundary layer. J. Math. Phys. 36, 137191.Google Scholar
Threfethen, L. N., Threfethen, A. E., Reddy, S. C. & Driscoll, T. A. 1993 Hydrodynamic stability without eigenvalues. Science 261, 578584.CrossRefGoogle Scholar