STABILITY OF VISCOUS-FLOW PAST A CIRCULAR-CYLINDER

A spectral method which employs trigonometric functions and Chebyshev polynomials is used to compute the steady, incompressible laminar flow past a circular cylinder. Linear stability methods are used to formulate a pair of decoupled generalized eigenvalue problems for the growth of symmetric and asymmetric (about the dividing streamline) perturbations. We show that, while the symmetric disturbances are stable, the asymmetric perturbations become unstable at a Reynolds number about 40 with a Strouhal number about 0. 12. The critical conditions are found to depend on the size of the computational domain in a manner similar to that observed in the laboratory.