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A model of defect-induced pairing in mixing layers

Published online by Cambridge University Press:  26 April 2006

Ruixin Yang ,
Frederic K. Browand ,
Pierre Coullet  and
Patrick Huerre
Ruixin Yang
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, CA 90089-1191, USA Present address: Institute for Computational Sciences & Informatics, George Mason University, Fairfax, VA 22030-4444, USA.
Frederic K. Browand
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, CA 90089-1191, USA
Pierre Coullet
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, CA 90089-1191, USA Permanent address: Institut Nonlinéaire de Nice, Université de Nice, Parc Valrose, 06108 Nice, France.
Patrick Huerre
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, CA 90089-1191, USA Present address: Laboratoire d’hydrodynamique (LADHYX), Ecole Polytechnique. 91128 Palaiseau Cedex, France.
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Abstract

Experiment have shown that the well-known vortex pairing process may take place first in defect regions where the fundamental structure is weakest. A model is introduced here to describe this defect-induced pairing process. The model is constructed in such a way that, in a certain parameter range, a stable fundamental mode and a stable subharmonic mode may coexist. The numerical simulation demonstrates that, when initial conditions consist of a dominant fundamental with one or more defects, the subharmonic component is preferentially generated in the cores of these defects. Moreover, the results also indicate that pairing may first commence wherever the fundamental mode is weakest provided the white-noise level of the subharmonic is high enough. The numerical results are in good agreement with experimental observations.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 248 , March 1993 , pp. 403 - 423
Copyright
© 1993 Cambridge University Press

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