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Optimal disturbances in swept Hiemenz flow

Published online by Cambridge University Press:  26 April 2007

ALAN GUÉGAN
Affiliation:
Laboratoire d'Hydrodynamique (LadHyX), CNRS-École Polytechnique, F-91128 Palaiseau, France
PATRICK HUERRE
Affiliation:
Laboratoire d'Hydrodynamique (LadHyX), CNRS-École Polytechnique, F-91128 Palaiseau, France
PETER J. SCHMID
Affiliation:
Laboratoire d'Hydrodynamique (LadHyX), CNRS-École Polytechnique, F-91128 Palaiseau, France

Abstract

The initial perturbation with the largest transient energy growth is computed in the context of the swept leading-edge boundary layer. The highest energy amplification is found for perturbations which are homogeneous in the spanwise z-direction, although on shorter time scales the most amplified disturbances have a finite spanwise wavenumber. In both cases the production term associated with the shear of the spanwise velocity is responsible for the energy amplification in the perturbation energy equation. A connection is made with the amplification mechanism exhibited by optimal perturbations in streaky boundary layers (Hoepffner et al. J. Fluid Mech. vol. 537, 2005, p.91) and the results are compared to the optimal Görtler–Hämmerlin disturbances computed by Guégan et al. (J. Fluid Mech. vol. 566, 2006, p. 11).

Type
Papers
Copyright
Copyright © Cambridge University Press 2007

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References

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