Unsteady flow past elliptic cylinders

Flow past elliptic cylinders is investigated for different Reynolds numbers and angles of attack by numerically solving the two-dimensional, unsteady incompressible Navier-Stokes equation. Results are obtained by using various numerical methods for consistency checks and also compared with available experimental results at Re = 3000. The Navier-Stokes equation is solved in stream-function-vorticity formulation using a finite difference method with third-and fifth-order upwinding for the convection terms. The pressure field is obtained by solving a Poisson equation and surface pressure values and vorticity information is integrated to obtain the sectional loads and pitching moment. Specific results are provided for Re = 3000 and 10 000 for different parameter combinations for the early stages of flow development. The effects of Reynolds number, angles of attack (ct) and thickness to chord ratios (t/c) are discussed through this two-dimensional direct numerical simulation (DNS). (C) 1997 Academic Press Limited.