A generalized hydrodynamic computational model for rarefied and microscale diatomic gas flows

On the basis of Euʹs generalized hydrodynamics, a computational model is developed for the numerical simulation of rarefied and microscale diatomic gas flows. The rotational nonequilibrium effect is taken into account by introducing excess normal stress associated with the bulk viscosity of the gas. The computational model for diatomic gases reduces to the model for monatomic gases in the limit of vanishing bulk viscosity. The thermodynamically consistent computational model is applied to the one-dimensional shock wave structure and the two-dimensional hypersonic rarefied flow around a blunt body in order to demonstrate its capability and validate the numerical results. The general properties of the constitutive equations are also presented through a simple analysis. The numerical results show that the new generalized hydrodynamic computational model yields the solutions in qualitative agreement with experimental data and DSMC results in the case of the problems studied.