Linearized Boltzmann equation: a preliminary exploration of its range of applicability

We investigate the scaling behavior of non-linear solutions of the two dimensional driven cavity flow with respect to the Mach number. Accurate numerical solutions of the hard-sphere Boltzmann equation have been obtained by means of a novel deterministic method which combines a finite volume discretization of the free-streaming term with a Gauss-Hermite evaluation of the collision integral. The results are of interest for DSMC applications to low speed flows, since they reveal the strategy to rescale solutions obtained at relatively high Mach numbers down to smaller values.