Monochromatic waves in saturated porous materials with anisotropic permeability

In the paper we investigate the propagation conditions of monochromatic waves in a saturated poroelastic material described by a generalization of Biot's equations. This generalization concerns anisotropic properties of the permeability. Mechanical properties of the system are assumed to be described by isotropic constitutive relations but the permeability is given in terms of a tensor of tortuosity. In particular we analyze the propagation in one of the principal directions of this tensor. For this particular monochromatic wave we show the existence of the purely transversal wave. We prove the existence of two modes of such waves and investigate their behavior as functions of the frequency. A practical application in nondestructive testing of anisotropic materials is indicated.