Low-Speed Flow Simulation by the Gas-Kinetic Scheme

Abstract

This paper extends the gas-kinetic BGK-type scheme to low Mach number flows, and thus shows that incompressible flow solutions are accurately obtained from the BGK scheme in the low Mach number limit. The influence of boundary conditions, internal molecular degrees of freedomK, and the flow Mach numberMon the accuracy of the solutions of incompressible or nearly incompressible flow problems is quantitatively evaluated. The gas-kinetic scheme is tested carefully in two numerical examples, namely, the cavity flow problem and the flow passing a backward facing step problem. For the cavity flow problem, the numerical results from the gas-kinetic scheme under different Reynolds numbers compare well with Ghia's data. For the backward step problem, the numerical results are compared accurately with previously published experimental data.