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ESAIM: Proceedings, Vol. 7, 1999, 247-257
Third International Workshop on Vortex Flows
and Related Numerical Methods
http://www.emath.fr/proc/Vol.7/

COMPARISON OF VISCOUS AND INVISCID NUMERICAL SIMULATIONS OF THE START-UP VORTEX ISSUING FROM A SEMI-INFINITE FLAT PLATE

P.  LUCHINI⁽¹⁾, R.  TOGNACCINI⁽²⁾

⁽¹⁾Dipartimento di Ingegneria Aerospaziale, Politecnico di Milano, Italia, luchini@aero.polimi.it
⁽²⁾Dipartimento di Progettazione Aeronautica, Universita` di Napoli "Federico II", Italia, rtogna@unina.it

Abstract:

Subject of the present work is the start-up vortex issuing from a sharp trailing edge accelerated from rest in still air. A numerical simulation of the flow has been performed in case of a semi-infinite flat plate by solving the Navier-Stokes equations in the Psi-Omega formulation. The new numerical algorithm is based on a fast multigrid implicit integration of the difference equations in an unstructured mesh that is dynamically built to minimize the computational costs. The results, compared with inviscid lumped-vortex simulations, show the appearance of instabilities that quickly destroy the regular structure of the spiral vortex. This analysis gives a contribution to the understanding of a physical problem still discussed in the literature and raises the question whether the application of numerical regularization procedures can tend to stabilize a phenomenon even when its physical nature is unstable.
    Contents  | PDF file part.I (2891 KB)  | PDF file part.II (1301 KB)