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ESAIM: Proceedings, Vol. 7, 1999, 325-334
Third International Workshop on Vortex Flows
and Related Numerical Methods
http://www.emath.fr/proc/Vol.7/

Interaction Vortex - Boundary Layer :
Numerical study of wall mechanisms

S. Pellerin* and A. Giovannini

* LIMSI-CNRS, UPR 3251, BP 133,
F-91403 Orsay Cedex, France,
pellerin@limsi.fr

Institut de Mécanique des Fluides de Toulouse,
UMR 5502 CNRS/INP-UPS,
Université Paul Sabatier, 118 Route de Narbonne,
F-31062 Toulouse Cedex, France,
giovannini@imft.fr


Abstract:

The interactions between a coherent vortex structure and a flat plate boundary layer are investigated. The unsteady numerical method used associates the Vortex-In-Cell algorithm for the convection step to the Random Walk algorithm for the diffusion one. The boundary layer is discretized by a large number of vortices, 105. An appropriate choice of discretization parameters leads to a good solution for the flat plate and exhibits a minimal numerical dissipation. Interactions are studied for different Reynolds numbers, for positive and negative vortices. The Lighthill?s mechanism of production of vorticity is observed. In the case of a negative vortex, a recirculation zone appears and a secondary structure with positive vorticity is created inside the boundary layer. The ejection of this structure induces the rebound of the main vortex. The wall mechanisms, particularly the study of Cf and Cp evolutions, confirm previous behaviors.
 
Contents | PDF file (1546 KB)