On the use of several compact methods for the study of unsteady incompressible viscous flow for outer problems (II)

The present work is concerned with the Navier-Stokes equations in their vorticity stream function formulation discretized spatially by compact algorithms. Four different space discretizations for the vorticity are compared for the case of an impulsively started circular cylinder. The four schemes include a standard upwind scheme with second order corrections implemented in connection with an A.D.I. method in time, either in conservative form or convective form, and two formally fourth-order accurate schemes of the 'mehrstellen' type. It was found that wiggles determine the quality of the mesh resolution, and that upwinding must be switched off at the rear stagnation point in order to protect the symmetry of the flow.