ON STEADY FLOW PAST A ROTATING CIRCULAR-CYLINDER AT REYNOLDS-NUMBERS 60 AND 100

The unsteady flow past a rotating circular cylinder approaches a steady state after a large enough time for low Reynolds numbers. However the most recent time-dependent calculations performed by Badr et al. (Comput. Fluids 17, 579; 1989) indicated that the flow does not tend to a steady state for higher Reynolds numbers, e.g. Re = 60 and 100. In this work steady solutions have been obtained by solving the time-independent Navier-Stokes equations for Re = 60 and 100 and the rotational parameter, alpha, in the range of 0 less-than-or-equal-to alpha less-than-or-equal-to 1. The objective is to extend the Reynolds number range for reliable data on the steady flow, particularly with regard to the lift and drag coefficients. A numerical scheme which avoids the difficulties in satisfying the boundary conditions at large distances from the cylinder is employed. Further, series expansion solutions are obtained which are valid at small values of alpha, but the results are found to be applicable over a wide range of values of alpha. The flow pattern, the surface vorticity and pressure coefficient are also presented.