Evolution equations for dissipative bodies and hyperbolicity (Q761312)

A model of Navier-Stokes-Fourier theory is studied, in which the propagation of thermal and viscous effects is not instantaneous. Using the thermodynamical properties of materials with internal variables, it is shown that, for the model elaborated by \textit{T. Ruggeri} [Acta Mech. 47, 167-183 (1983; Zbl 0543.76050)] the invariance of the internal energy and pressure (the nonequilibrium values are equal with those at equilibrium) leads to a hyperbolic system of equations for heat conducting and viscous fluids. In the last part an application is given to the evolution equation for heat conduction in dielectric crystals.