Low-speed flow simulation by the gas-kinetic scheme

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 boundar y conditions, internal molecular degrees of freedom K, and the Row Mach num ber M on the accuracy of the solutions of incompressible or nearly incompre ssible flow problems is quantitatively evaluated. The gas-kinetic scheme is tested carefully in two numerical examples, namely, the cavity flow proble m 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 probl em, the numerical results are compared accurately with previously published experimental data. (C) 1999 Academic Press.