B. Kevin Edgar, S.E. Anderson, and Paul Woodward
Army High Performance Computing Research Center, Minneapolis, MN
Army Research Laboratory, Aberdeen, MA
(full size: 218k)
Two PPM simulations of the Mach 4 flow of air about a circular cylinder in 2-D are shown here. The density distributions in these snap shots of the unsteady flows are shown, with a highly nonlinear color map which has been chosen to bring out detailed features in the wake. In the simulation at the bottom, a grid of 8 million zones has been used, while at the top only 2 million zones have been employed. Both simulations were performed on the CM-5 Connection Machine of the AHPCRC running at 8 Gflops on this application. The extent to which the computed results have converged to a limit solution is illustrated by a comparison of these two density distributions. Of course, individual eddy features differ, but the general features of the flow agree. Most sensitive to grid refinement is the small area where the tip of the region of recirculating air behind the cylinder joins the tail shocks and the turbulent wake. These results represent a new technique for computing time depedent flows of this type which permits very natural and effective parallel implementations on machines with large numbers of processors and a distributed memory architecture.