Direct particle simulation on the Connection Machine CM-2

Abstract

Particle simulation is a useful technique for analyzing low density flows. The Connection Machine CM-2 is a useful test bed for studying the fine-grain data objects decomposition and the coarse-grain domain decomposition single instruction multiple datastream (SIMD) approaches to particle simulation. Both approaches are investigated for the model problem of uniform flow through a channel and the algorithms required for the SIMD domain decomposition approach are presented. For this model problem, the domain decomposition approach is superior to the data objects decomposition approach with an average particle update time of 2.9 μs compared with 5.1 μs on an 8K processor CM-2. An unresolved issue with the domain decomposition approach is the effect of a poor partitioning on flows with real geometries. Initial results with the channel flow problem indicate that a poor partitioning has only a small (15%) detrimental effect on the overall performance.