Kinetics of the adsorption–desorption process with diffusional relaxation is studied by Monte-Carlo simulations on a square lattice. At each Monte-Carlo step three independent processes proceeding in parallel are attempted: adsorption, desorption and diffusion. The time is measured by the...

Two Bhatnagar–Gross–Krook (BGK) models for isothermal binary fluid systems—the classical single relaxation time model and a split collision term model—are discussed in detail, with emphasis on the diffusion process in perfectly miscible ideal gases. Fluid equations, as well as the...