Modified Generalized Hard Sphere Collision Model for Direct Simulation Monte Carlo Calculations

摘要

The GHS model can be modified to limit the collision probability at low collision speeds. This improves the computational efficiency both because the number of possible collision partners that must be tested is dramatically reduced and because the collision rate is lower. No more than 15% extra computational time is required, compared with the VHS model. For argon at T ≈ 100 K, the theoretical viscosity is changed by less than 2.5%, and this difference decreases rapidly as T increases. The modified viscosity is in better agreement with recommended viscosity values. This modified generalized hard sphere model can be used in DSMC simulations, where, to obtain realistic viscosity behavior at low T, it is necessary to model the effect of the attractive portion of the intermolecular potential.