Simulation of flows around cylinders by a Lagrangian vortex scheme

A method is presented for calculating flows around cylinders of arbitrary shape, which may be in an array. Vorticity is discretised and is moved in a Lagrangian time-stepping procedure by the vortex-in-cell method. The zero-velocity surface condition is maintained at each time step by representing the surface by a vortex sheet through a boundary integral calculation. Vorticity diffusion is simulated through random walks. Results are presented for an isolated circular cylinder in steady and oscillatory incident flows.