Parallel Numerical Computations of Projectile Flow Fields

Abstract : A time-marching, Navier-Stokes code, successfully used over a decade for projectile aerodynamics, was chosen as a test case and optimized to run on modern reduced instruction set computer (RISC)-based parallel computers. The parallelized version of the code has been used to compute the axisymmetric and three-dimensional (3-D) turbulent flow over a number of projectile configurations at transonic and supersonic speeds. In most of these cases, these results were then compared to those obtained with the original version of the code on a Cray C-90. Both versions of the code produced the same qualitative and quantitative results. Considerable performance gain was achieved by the optimization of the serial code on a single processor. Parallelization of the optimized serial code, which uses loop-level parallelism, led to additional gains in performance. The original algorithm remained unchanged. Recent runs on a 128-processor Origin 2000 have produced speedups in the range of 1026 over that achieved when using a single processor on a Cray C-90. The original algorithm remained unchanged. Computed surface pressures were compared with the experimental data and were generally found to be in good agreement with the data.