Numerical Simulation of Shedding Pattern of Near Wake Vortices Behind a Circular Cylinder Near a Plane Boundary

Abstract

In this paper, flow past a circular cylinder is numerically simulated under the influence of a plane boundary. The vorticity-stream function formulation is used for a wide range of Reynolds numbers consistent of two-dimensional flow. The conventional finite difference implicit scheme is used by implementing the appropriate boundary conditions at all boundaries. The transition from twin vortex regime to vortex shedding regime is studied. The transition is delayed as the gap between the cylinder and wall decreases. The same is because of the interaction between the wake of the cylinder and the boundary wall vorticity. The results are compared with the previous observations of the inhibition of the vortex shedding for body placed inside a channel as well as near a plane wall. The unsteady vortex shedding regime from a pattern similar to the von-karman street when the cylinder is far from the plane wall to a single row of same sign vortices as the body approaches the wall. The separated vortex dynamics leading to this tropological modification is presented.