Details of the Computed Flowfield Over a Circular Cylinder at Reynolds Number 1200

The application of an upwind-biased implicit approximate factorization Navier-Stokes algorithm to the unsteady impulsive start-up flow over a circular cylinder at Reynolds number 1200 is described. The complete form of the compressible Navier-Stokes equations is used, and the algorithm is second-order accurate in both space and time. The drag on the cylinder is computed for early times in the start-up flow. The value of the local maximum drag as well as the time at which it occurs are predicted and compared to another computational result and experiment. The development with time of the shape and size of the separated vortical flow region is computed, as well as the time-variation of several boundary layer parameters and profile shapes. Computations, in general, show excellent agreement with experiment, although the present method predicts a more rapid onset of reversed flow on the cylinder than evidenced in experiment. The effect of grid density on the development of the unsteady flow is also shown.