A novel wall model, including inelastic fluid-wall collisions, molecular structure of the wall, and a long-ranged fluid-wall interaction, is used in molecular dynamics simulations of flow in two dimensions. For strong fluid-wall attraction the fluid velocity goes smoothly to zero at the wall; there is no velocity slip. In less dense fluids the velocity drops to zero in an ever-narrower region. Our results differ from standard kinetic theory but agree with Eu’s theory [Phys. Rev. A 36, 400 (1987)]. The nature of the fluid-wall interaction is important; repulsive walls give velocity slip.

• Received 9 September 1992

DOI:https://doi.org/10.1103/PhysRevLett.69.3491