DEVELOPMENT OF A NOVEL SOLVER FOR SIMULATION OF FLOWS FROM THE CONTINUUM REGIME TO THE RAREFIED REGIME

Abstract

A novel solver is developed in this thesis to simulate flows from the continuum regime to the rarefied regime. The novel solver is developed based on the framework of gas kinetic flux solver (GKFS), and it combines some good features of discrete velocity method (DVM) and moment method. Like GKFS, the governing equations are discretized by finite volume method, and the numerical fluxes are reconstructed by the local solution to the Boltzmann equation. Inspired by moment method, this local solution is reconstructed with the help of Grad’s distribution function, which enables the novel solver to simulate flows in both the continuum and rarefied regimes. Thanks to this reconstruction, the novel solver avoids the discretization of particle velocity space, and the numerical fluxes can be expressed explicitly. These two features make the novel solver quite efficient for both the continuum and rarefied flows.