FULL FREQUENCY-RANGE TRANSIENT SOLUTION FOR COMPRESSIONAL WAVES IN A FLUID-SATURATED VISCOACOUSTIC POROUS-MEDIUM

An analytical transient solution is obtained for propagation of compre ssional waves in a homogeneous porous dissipative medium. The solution , based on a generalization of Blot's poroelastic equations, fields fo r the low- and high-frequency ranges, and includes viscoelastic phenom ena of a very general nature, besides the Blot relaxation mechanism. T he viscodynamic operator is used to model the dynamic behaviour associ ated with the relative motion of the fluid in the pores at all frequen cy ranges. Viscoelasticity is introduced through the standard linear s olid which allows the modelling of a general relaxation spectrum. The solution is used to study the influence of the material properties, su ch as bulk moduli, porosity, viscosity, permeability and intrinsic att enuation, on the kinematic and dynamic characteristics of the two comp ressional waves supported by the medium. We also obtain snapshots of t he static mode arising from the diffusive behaviour of the slow wave a t low frequencies.