SIMULATION OF SLIGHTLY VISCOUS EXTERNAL FLOW BY A GRID-PARTICLE DOMAIN DECOMPOSITION METHOD

A grid-particle domain decomposition method is proposed to simulate tw o-dimensional, slightly viscous external flow. In this method the wall -vorticity generation, together with the subsequent diffusion and conv ection in the near wake, is simulated in a deterministic way by an eff icient finite-difference scheme. Beyond the near wake, the flow is sim ulated by an inviscid vortex method in which the velocity calculation for moving vortex particles is speeded up by a fast, adaptive multipol e scheme. A proper treatment of the grid-particle interface is also pr esented. Some results are given to demonstrate both the early stage an d the long-term simulations of flow past a circular cylinder, at a mod erately high Reynolds number.