Numerical Methods for Separated Flow Solutions around a Circular Cylinder

Numerical solutions of the Navier-Stokes equations were obtained for separated flows around a circular cylinder at Reynolds numbers 40, 80, and 200. The flowfields were obtained by using three finite-difference techniques. The implicit scheme solved by matrix factorizations gave the best accuracy and used the least computer time. The flow pattern in the recirculating region of a circular cylinder begins to oscillate as the Reynolds number exceeds 40. The calculated drag coefficients, separation angles, and Strouhal numbers were compared with available experimental data. Computational inaccuracy resulting from numerical approximations needs to be identified before a complicated flow phenomenon can be realistically analyzed.