Drag and flow reversal in mixed convection past a heated sphere

Axisymmetric simulation of mixed convection past a heated sphere presented in a recent paper of Mograbi and Bar-Ziv J. Aerosol Sci. 36, 387 2005 reveals a " huge " recirculation in the opposing flow configuration at very small Reynolds numbers and at Richardson numbers exceeding unity, the...

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Bibliographic Details
Published in:Physics of fluids (1994) 2009, Vol.21, p.54104-54104
Main Authors: Kotouč, Miroslav, Bouchet, Gilles, Dušek, Jan
Format: Article
Language:English
Subjects:
Fluid mechanics
Mechanics
Physics
Online Access:Get full text
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Summary:Axisymmetric simulation of mixed convection past a heated sphere presented in a recent paper of Mograbi and Bar-Ziv J. Aerosol Sci. 36, 387 2005 reveals a " huge " recirculation in the opposing flow configuration at very small Reynolds numbers and at Richardson numbers exceeding unity, the size of which seems to adjust to a computational domain of any size. In this paper we show that, for Reynolds numbers as low as one, the flow is nonaxisymmetric and that its three dimensionality brings the recirculation within finite bounds. At higher Reynolds numbers Re, the cases of Re = 10 and 100 are considered at a fixed Prandtl number of 0.72. The flow becomes very soon not only three dimensional but also chaotic. Especially at higher Reynolds numbers 100, the arising convective structures do not resist the opposing flow and do not travel upstream more than several sphere diameters.
ISSN:1070-6631
1089-7666
DOI:10.1063/1.3139304