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Phase decorrelation of coherent structures in a free shear layer

Published online by Cambridge University Press:  26 April 2006

Chih-Ming Ho
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, CA 90089-1191, USA
Yitshak Zohar
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, CA 90089-1191, USA
Judith K. Foss
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, CA 90089-1191, USA
Jeffrey C. Buell
Affiliation:
Center for Turbulence Research, NASA-Ames Research Center, Moffett Field, CA 94035, USA Present address: CENTRIC Engineering Systems, Inc., 3801 E. Bayshore Road, Palo Alto, CA 94303, USA.

Abstract

The vortices near the origin of an initially laminar mixing layer have a single frequency with a well-defined phase; i.e. there is little phase jitter. Further downstream, however, the phase jitter increases suddenly. Even when the flow is forced, this same transition is observed. The forcing partially loses its influence because of the decorrelation of the phase between the forcing signal and the passing coherent structures. In the present investigation, this phenomenon is documented and the physical mechanism responsible for the phase decorrelation is identified.

Type
Research Article
Copyright
© 1991 Cambridge University Press

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