Discrete‐velocity collision dynamics for polyatomic molecules

A multispeed discrete‐velocity molecular model of a rarefied gas is developed which permits quantitatively accurate simulation of mixtures of molecules of different mass which have both translational and internal rotational energies. In particular, the molecules are represented as having three discrete velocity components and a single discrete internal energy that does not directly affect the translational motion. During binary collisions, rotational and translational kinetic energies are exchanged according to a phenomenological model. Results are presented for the thermal relaxation to equilibrium of mixtures of H₂ and Ne, N₂ and O₂, and N₂ and CO₂. Good agreement is found with the corresponding continuous‐velocity results.