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Asymmetric flows and instabilities in symmetric ducts with sudden expansions

Published online by Cambridge University Press:  12 April 2006

W. Cherdron ,
F. Durst  and
J. H. Whitelaw
W. Cherdron
Affiliation:
Sonderforschungsbereich 80, Ausbreitungs-und Transportvorgänge in Strömungen, Universität Karlsruhe, Germany
F. Durst
Affiliation:
Sonderforschungsbereich 80, Ausbreitungs-und Transportvorgänge in Strömungen, Universität Karlsruhe, Germany
J. H. Whitelaw
Affiliation:
Sonderforschungsbereich 80, Ausbreitungs-und Transportvorgänge in Strömungen, Universität Karlsruhe, Germany Permanent address: Mechanical Engineering Department, Imperial College, London.
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Abstract

Flow visualization and laser-Doppler anemometry have been used to provide a detailed description of the velocity characteristics of the asymmetric flows which form in symmetric, two-dimensional, plane, sudden-expansion geometries. The flow and geometry boundary conditions which give rise to asymmetric flow are indicated, and the reason for the phenomenon is shown to lie in disturbances generated at the edge of the expansion and amplified in the shear layers. The spectral distributions of the fluctuations in velocity are quantitatively related to the dimensions of the two unequal regions of flow recirculation. It is also shown that the intensity of fluctuating energy in these low Reynolds number flows can be larger than that in corresponding turbulent flows.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 84 , Issue 1 , 16 January 1978 , pp. 13 - 31
Copyright
© 1978 Cambridge University Press

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