Investigation of Nonequilibrium Internal Energy Excitation in Shock Waves by means of a Spectral-Lagrangian Boltzmann Solver

摘要

We propose to extend an existing spectral-Lagrangian numerical method for the Boltzmann equation for a pure gas (without internal energy) to a multi energy level gas. The numerical method is based on the weak form of the collision operator and can be used with any type of cross-section model. The formulation is developed in order to account for both elastic and inelastic collisions, the latter being responsible for internal energy excitation. Applications focus on the investigation of nonequilibrium flows across normal shock waves. Numerical solutions are obtained for both pure gases and mixtures at different values of the free-stream Mach number. Computational results are compared with those obtained by means of the DSMC method in order to assess the accuracy of the proposed numerical method.