SRT-LBM and MRT-LBM comparison for a lid-driven gas microflow

Abstract

In this paper, single relaxation time (SRT) and multi-relaxation time (MRT) lattice Boltzmann method are used to simulate gas flow in a lid-driven micro-cavity. Simulation of such microflow requires suitable boundary conditions. In this work, a diffuse scattering boundary condition and a combination of bounce-back and specular boundary conditions are employed to obtain the slip velocity at the walls. The computations are carried out mainly for the slip and early transition regimes. The effect of the Knudsen number on the velocities profile and streamlines contours are shown. In the slip regime, the obtained numerical results agree well with existing results for both approaches. Whereas, in the transition regime, MRT-LBM gives good results contrary to the SRT-LBM which the validity breaks down.