Sensitivity Analysis of Fluid Flow to Slip Coefficient Using Lattice Boltzmann Method

In this paper the effect of slip coefficient on incompressible gas slip flow and the sensitivity of fluid flow behavior to this coefficient in a rough microchannel are investigated using the lattice Boltzmann method. Local slip velocity, streamline contour plots and average Poiseuille number in hydrodynamically developed region are studied and presented. Sensitivity analysis is performed in different relative roughness heights as well as different densities of surface roughness and for different Knudsen numbers. It is shown that as the relative roughness height increases, the sensitivity of Poiseuille number to this coefficient, which is illustrated by the slope of the Poiseuille number versus slip coefficient curve, is increased, while negligible sensitivity difference is seen when different roughness densities are studied. In near continuum flow, the slope of the Poiseuille number curve versus slip coefficient in rough and smooth surface is different, and this trend becomes more similar as the Knudsen number increases.