Shock waves in carbon dioxide: Simulations using different kinetic-theory models

Abstract

Shock wave structure in carbon dioxide is studied on the basis of several continuum models and compared to the solution obtained using the kinetic approach. The problem is solved in the frame of one- A nd two-temperature Euler equations as well as Navier-Stokes equations accounting for the bulk viscosity. The Rankine-Hugoniot relations with constant specific heat ratio fail to predict accurately the final equilibrium state in polyatomic gases. A good qualitative agreement of the solutions obtained using the continuum and kinetic approaches is shown. Taking into account the bulk viscosity leads to a considerable increase in the shock wave width; its variation in a flow modifies the profiles of gas-dynamic parameters. In the multi-temperature approach, solving the Euler equations coupled to the relaxation equation for the vibrational energy provides the results similar to those obtained within the kinetic approach taking into account the effect of bulk viscosity.