MOLECULAR-DYNAMICS SIMULATIONS OF FLOW WITH BINARY DIFFUSION IN A 2-DIMENSIONAL CHANNEL WITH ATOMICALLY ROUGH WALLS

Binary diffusive-convective gas flows in a two-dimensional channel with atomically rough walls were studied by molecular-dynamics simulations. We found that, similar to the behavior of monocomponent flows investigated in our earlier work [Phys. Rev. A 42, 4688 (1990)], the no-slip condition arises when the mean free path in the gas mixture is of the same order of magnitude as or smaller than the atomic-wall-roughness amplitude. However, if there are concentration gradients along the wall, the component velocities at the wall do not vanish. Thus the no-slip condition is established via the mutual cancellation of the nonvanishing, opposing slip velocities of the components.