Effect of viscosity on pseudo-Scholte wave propagation at liquid/porous medium interface.

ABSTRACT

A theory of pseudo-Scholte wave propagating in a saturated porous medium loaded on its interface by a viscous compressible liquid is described. The porous medium is simulated by the Biot theory with high-frequency correction, and the overlying liquid is simulated by the linearized Navier-Stokes equation. An analytical expression for the complex dispersion equation of pseudo-Scholte wave through boundary conditions is established. Then the Riemann sheets related to body waves are discussed and the real and imaginary parts of the complex dispersion equation are separated and solved numerically. The resulting phase velocity, attenuation, as well as displacement and pressure fields are analyzed and comparisons are drawn with the non-viscous model. Finally, a set of parametric analyses is carried out to describe the effects of the phase velocity ratios of the S-wave in the porous medium to Ls-mode in overlying liquid on phase velocity and attenuation of the pseudo-Scholte waves.