Determination of material functions through second sound measurements in a hyperbolic heat conduction theory

In a previous paper 1], numerical solutions to initial-boundary value problems for a semi-empirical model of heat conduction were compared with available experimental results.

In the present paper, we modify the model by introducing more realistic approximations of constitutive functions, based on measured heat conductivities and second sound speeds for NaF at low temperatures (10…20° K). We achieve good accordance between measured second sound pulses and numerical solutions in the temperature range covered by experiments, and reasonable behaviour even beyond this interval. Especially, a passage to the diffusive regime of the classical Fourier law is possible.