REFINED NUMERICAL INTEGRATION OF THE NAVIER-STOKES EQUATIONS: THE IMPULSIVELY STARTED CIRCULAR CYLINDER AT RE=3000 (FOURIER, SUPERCOMPUTER, FLUID DYNAMICS, UNSTEADY)

A numerical model is developed on a Discrete Fourier Transform-finite difference algorithm to determine the time dependent flow field around an infinitely long circular cylinder. The modeling involves the use of a super computer (CDC CYBER 205) to integrate the Navier-Stokes equations, the mathematical model of the problem. The computational procedure takes advantage of the one dimensional Fast Fourier Transform (FFT), developed for the CDC CYBER 205 supercomputer, in the evaluation of the nonlinear terms. A fourth order direct integration scheme is used in the radial direction, and a fourth order predictor-corrector algorithm is implemented to perform the integration in time. Symmetric and non-symmetric flow conditions at Reynolds number of 3000 have been simulated to allow observation of the formation of high order vortices in the wake of the cylinder. The calculated fields have been compared with experimental results in analogous conditions from the related literature. Some new phenomena indicated in the flow evolution description for both the symmetric and non-symmetric flow pattern are revealed. The effect of the skin friction and pressure on the surface of the cylinder with respect to the drag and lift coefficients are also calculated