A HYBRID VORTEX METHOD FOR FLOWS OVER A BLUFF-BODY

A hybrid vortex method was developed to simulate the two-dimensional v iscous incompressible flows over a bluff body numerically. It is based on a combination of the diffusion-vortex method and the vortex-in-cel l method by dividing the how field into two regions. In the region nea r the body surface the diffusion-vortex method is used to solve the Na vier-Stokes equations, while the vortex-in-cell method is used in the exterior domain. Comparison with results obtained by the finite differ ence method, other Vortex methods and experiments shows that the prese nt method is well adapted to calculate two-dimensional external flows at high Reynolds number. It is capable of calculating not only the glo bal characteristics of the separated flow but also the evolution of th e fine structure of the flow field with time precisely. The influence of the grid system and region decomposition on the results will also b e discussed.