Numerical simulation for gas microflows using Boltzmann equation

A computational method based on a kinetic model Boltzmann equation has been developed for microscale low speed flows. The results obtained with the method are compared with those of the direct simulation Monte Carlo method and experiments for supersonic flows. Numerical results for low speed flows over a microcircular cylinder and a microsphere are also obtained with the method, while it is difficult to obtain the low speed flow results with the direct simulation Monte Carlo method. Results of the Navier–Stokes equations with slip boundary conditions generally agree with those of the kinetic model Boltzmann equation if the Knudsen number is less than 0.1. A kinetic/continuum hybrid method has also been developed. The hybrid method may be a promising tool for analyzing whole flow regimes from free molecule to continuum flows.