Numerical Simulation of Unsteady Flow around Three Dimensional Bluff Bodies by an Advanced Vortex Method

Recently, the present authors have developed a vortex method for analyses of various two and three-dimensional unsteady flows, aiming its application to various engineering problems. In this paper, a new scheme is proposed for the vorticity creation at a solid surface of a three-dimensional body, in which a number of nascent vortices are introduced in the flow field according to the diffusion and the convection of the vorticity near the solid surface. As an example, the new scheme is applied to the analyses of starting flows around two kinds of bodies : a sphere and a prolate spheroid. As a result of this calculation, the boundary layer separation from the body surface and the development of vortical wake have been reasonably simulated.