Molecular-dynamics simulation of flow in a two-dimensional channel with atomically rough walls.

Abstract

Fluid flows in a two-dimensional channel with atomically rough walls were studied by molecular-dynamics simulations. Both sinusoidally and randomly roughened walls with various roughness amplitudes A were used. It was found that the no-slip condition arises when the molecular mean free path l is comparable with A. Therefore the ratio l/A should be employed to validate the no-slip condition, rather than the traditionally used ratio of the mean free path to the channel or tube diameter (Knudsen number).