Propagation of coupled porosity and fluid-concentration waves in isotropic porous media

This article presents an application of a theory, previously formulated in the framework of rational extended irreversible thermodynamics, to describe the thermal, mechanical and transport properties of a porous medium filled by a fluid. Starting from the anisotropic rate equations for the porosity field, its flux, and for the heat and fluid-concentration fluxes, the isotropic case is studied when the body has symmetry properties invariant for all rotations and inversions of the frame axes. Furthermore, the phenomenological tensors have special symmetry properties coming from the used theoretic model. Then the propagation in one direction of coupled porosity and fluid-concentration waves is investigated. The dispersion relation is carried out and the wave propagation velocities as functions of the wavenumber are calculated and represented in a diagram for a given numerical set of the several coefficients characterizing the considered porous media. The results obtained in this article can be applied in several sciences such as seismology, medical sciences, geology and nanotechnology, where there is propagation of high-frequency waves.