The effect of surface roughness on rarefied gas flows by lattice Boltzmann method

This paper studies the roughness effect combining with effects ofrarefaction and compressibility by a lattice Boltzmann model forrarefied gas flows at high Knudsen numbers. By discussing the effectof the tangential momentum accommodation coefficient on the roughboundary condition, the lattice Boltzmann simulations of nitrogenand helium flows are performed in a two-dimensional microchannelwith rough boundaries. The surface roughness effects in themicrochannel on the velocity field, the mass flow rate and thefriction coefficient are studied and analyzed. Numerical results forthe two gases in micro scale show different characteristics frommacroscopic flows and demonstrate the feasibility of the latticeBoltzmann model in rarefied gas dynamics.