Parallel Particle Simulations of Low-Density Fluid Flows

S. J. Plimpton and T. J. Bartel, in Proc of High Performance Computing 1994, San Diego, CA, April 1994, p 31.

Direct Simulation Monte Carlo (DSMC) is a simulation technique that uses particles to model fluids at low densities where continuum formulations break down. Monte Carlo rules are used to perform particle collisions and chemical reactions and a grid is used to locate nearby particles. We describe our implementation of a large-scale DSMC model on the thousand-processor nCUBE 2 and Intel Paragon machines. It includes body-fitted irregular grids and particle weighting to reduce the numbers of particles and grid cells that must be used. Our parallel methods for load-balancing and performing irregular communication on the distributed-memory machines are also discussed. The parallel machines have enabled us to run large simulations (10^7 particles, 10^4 grid cells, 10^4 timesteps) at speeds up to 40 times faster (on our nCUBE 2) than on a Cray Y-MP processor. For illustration purposes, we include results from some of these large-scale simulations.

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