Numerical simulation of vortex shedding past a circular cylinder under theinfluence of buoyancy

Flow past an isolated circular cylinder is numerically simulated, under the influence of aiding and opposing buoyancy. A modified velocity correction procedure is incorporated. Galerkin weighted residual formulation is employ ed for spatial discretization along with a second-order Runge-Kutta (R-K) t ime integration scheme. The influence of buoyancy on the Nusselt number, wa ke structures, temporal lift and drag forces have been studied. At low Reyn olds numbers (for, e.g., Re=20-40), buoyancy opposing the flow could trigge r vortex shedding. The degeneration of the Karman vortex street into twin v ortices is numerically simulated for a heated cylinder. The two zones of vo rtex shedding and twin vortices are demarcated. (C) 1999 Elsevier Science L td. All rights reserved.