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Discrete-vortex simulation of a turbulent separation bubble

Published online by Cambridge University Press:  20 April 2006

Masaru Kiya
Affiliation:
Faculty of Engineering, Hokkaido University, Sapporo, 060, Japan
Kyuro Sasaki
Affiliation:
Faculty of Engineering, Hokkaido University, Sapporo, 060, Japan
Mikio Arie
Affiliation:
Faculty of Engineering, Hokkaido University, Sapporo, 060, Japan

Abstract

The discrete-vortex model is applied to simulate the separation bubble over a two- dimensional blunt flat plate with finite thickness and right-angled corners, which is aligned parallel to a uniform approaching stream. This flow situation is chosen because, unlike most previous applications of the model, the separation bubble is supposed to be strongly affected by a nearby solid surface. The major objective of this paper is to examine to what extent the discrete-vortex model is effective for such a flow. A simple procedure is employed to represent the effect of viscosity near the solid surface; in particular, the no-slip condition on the solid surface. A reduction in the circulation of elemental vortices is introduced as a function of their ages in order to represent the three-dimensional deformation of vortex filaments, An experiment was also performed for comparison purposes.

The calculation yielded reasonable predictions of the time-mean and r.m.s. values of the velocity and the surface-pressure fluctuations, together with correlations between their fluctuating components, over most of the separation bubble. The interrelation between instantaneous spatial variations of the surface-pressure and velocity fluctuations were also obtained. A comparison between the calculated and measured results suggests that, in the real flow, the three-dimensional deformation of vortex filaments will become more and more dominant as the reattachment point is approached.

Type
Research Article
Copyright
© 1982 Cambridge University Press

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