Finite-speed propagation of heat: a nonlocal and nonlinear approach

A linear weakly nonlocal and finite-speed theory of heat conduction in rigid solids was presented by Lebon and Grmela in Phys. Lett. A 214 (1996) 184. In the present paper, this work is extended to a fully nonlinear theory. The extension is based on the requirement that the Hamiltonian structure already present in the linear approach is kept in the nonlinear theory. From the physical point of view, this requirement guarantees that solutions to the governing equations agree with certain fundamental experimental observations. During the time evolution, the total energy is shown to remain constant and the total entropy is shown to grow.