Algorithms for the Calculation of Transport Coefficients

Abstract

In order to define transport terms in the governing equations, it is necessary to calculate the coefficients of viscosity, thermal conductivity, diffusion, and relaxation pressure. In the present Chapter, algorithms for the calculation of transport coefficients are considered for different levels of accuracy of the description of non-equilibrium flows: in the state-to-state and quasi-stationary approaches. In contrast to weak nonequilibrium gases, the transport coefficients under the strong non-equilibrium conditions depend not only on the gas temperature but also on other parameters of the flow, which characterize the deviation from equilibrium, namely, on the vibrational level populations in the state-to-state approach and on the temperature of non-equilibrium modes in the quasi-stationary approximations. This results in some peculiarities in the transport coefficients discussed in this Chapter.