DYNAMICAL INTERPRETATION OF 2ND-ORDER CONSTITUTIVE EQUATIONS OF HYDRODYNAMICS

The classical linear irreversible thermodynamics is extended to the non-linear range. Heat conductingviscous isotropic fluid systems are considered. It is assumed that the non-equilibrium entropy depends, besides on its classical variables, on the heat flux and the viscous pressure tensor. Representation theorems of isotropic functions are used to determine the form of the state equations, the entropy flux and the generalized constitutive equations. The latter are viewed as evolution equations for the heat flux and the viscous pressuretensor. The theory is compared with the thirteen-moments method of the kinetic theory of gases, and it is seento generalize previous formulations of so-called extended irreversible thermodynamics. © by Walter de Gruyter & Co.