A GENERALIZED HARD-SPHERE MODEL FOR MONTE-CARLO SIMULATION

A new molecular model, called the generalized hard-sphere, or GHS model, is introduced. This model contains, as a special case, the variable hard-sphere (VHS) model of Bird [Rarefied Gas Dynamics, edited by S. S. Fisher (AIAA, New York, 1981), Part 1, p. 239] and is capable of reproducing all of the analytic viscosity coefficients available in the literature that are derived for a variety of interaction potentials incorporating attraction and repulsion. In addition, a new procedure for determining interaction potentials in a gas mixture is outlined. Expressions needed for implementing the new model in the direct simulation Monte Carlo (DSMC) methods are derived. This development makes it possible to employ interaction models that have the same level of complexity as used in Navier-Stokes calculations.