Nonequilibrium diffusive gas dynamics: Poiseuille microflow

Abstract

We test the recently developed hierarchy of diffusive moment closures for gas dynamics together with the near-wall viscosity scaling on the Poiseuille flow of argon and nitrogen in a one micrometer wide channel, and compare it against the corresponding Direct Simulation Monte Carlo computations. We find that the diffusive regularized Grad equations with viscosity scaling provide the most accurate approximation to the benchmark DSMC results. At the same time, the conventional Navier–Stokes equations without the near-wall viscosity scaling are found to be the least accurate among the tested closures.