Kinetic Models for a Gas with Internal Structure

Kinetic model equations for a polyatomic gas have been obtained by employing a diagonal approximation in the truncation of the linearized operator of the Wang Chang-Uhlenbeck equation. These models possess an H theorem, and a Chapman-Enskog analysis of these equations yields the correct transport coefficients, such as bulk viscosity, viscosity, and thermal conductivity for translational and internal degrees of freedom. The restrictions of the Wang Chang-Uhlenbeck equation are discussed, and it is believed that these model equations should be most useful in the study of those kinetic problems involving scalar transport phenomena, in particular, sound propagation, heat transfer, and shock structure.