Reduction of simulation cost and error for particle simulations of rarefied flows (Q1316028)

The computational cost in simulating a steady, rarefied gas flow by use of a particle method is shown to be greatly reduced if the simulation employs an average number of particles per cell that is greater than a certain (approximate) minimum. The minimum value depends on the rms level of statistical fluctuations judged acceptable in the resultant data and is found to be significantly greater than values often used in practice when two- and three-dimensional flows are simulated.