NEW SECOND-ORDER SLIP BOUNDARY CONDITION FOR SIMULATING HIGH-SPEED RAREFIED GAS FLOWS

Abstract

. In this paper, a new second-order slip boundary condition is proposed based on a combination of the Langmuir isothermal adsorption model on the solid surface and model of kinetic theory of gases. This new second-order slip condition is implemented into the open-source OpenFOAM software to employ with the rhoCentralFoam solver that solves Navier-Stokes-Fourier equations. Two basic cases to verify this new slip condition are the flat plate and circular cylinder in cross-flows. High-speed rarefied gas flows (Mach numbers 4 - 10) are selected to perform the simulations for the above two cases with working gases as argon and nitrogen. The results of the CFD slip velocities using new slip condition of gas flows over the surface are close to the DSMC results for all the cases considered, and they are better than those of the second-order slip condition published previously.