Applications of statistical mechanics in subcontinuum fluid dynamics

We show results of molecular dynamics studies of fluid flows in the Knudsen regime in which the mean free path is comparable to the system size. We elucidate the boundary conditions at the wall–fluid interface in such flows and find scenarios envisioned by Maxwell. We also find scenarios which do not agree with Maxwell's hypothesis. We focus primarily on the case of repulsive walls and discuss similarities and differences in behavior when the wall–fluid interaction is attractive or repulsive. Striking many body effects are found on increasing the fluid density as one interpolates between the dilute gas and the dense fluid regimes.