Kinetic and phenomenological theories for the linearized Burnett equations of a molecular gas

Abstract

The linearized Burnett equations for a molecular gas are obtained from a kinetic theory based on the Boltzmann equation, and from a phenomenological theory based on extended thermodynamics. The constitutive equation for the pressure tensor of a molecular gas has three terms that do not have appeared in the corresponding equation for a monatomic ideal gas. One is the well-known term proportional to divergence of velocity whose coefficient is the volume viscosity. The two others are proportional to Laplacians of the temperature and of the density, and are associated with athermal (or temperature) pressure and with adensity pressure, respectively.