Wave propagation and the frequency domain Green’s functions in viscoelastic Biot/squirt (BISQ) media

• Published in: International journal of solids and structures Vol. 44; no. 14; pp. 4784 - 4794
• Main Authors: Yang, Dinghui, Shen, Yiqing, Liu, Enru
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-07-2007
• Subjects: Biot/squirt (BISQ) model; Green’s function; Poroelasticity; Viscoelastic media; Wave propagation; Green’s function; Wave propagation; Poroelasticity; Viscoelastic media; Biot/squirt (BISQ) model
• ISSN: 0020-7683; 1879-2146
• DOI: 10.1016/j.ijsolstr.2006.12.001

In this paper, we examine the characteristics of elastic wave propagation in viscoelastic porous media, which contain simultaneously both the Biot-flow and the squirt-flow mechanisms (BISQ). The frequency-domain Green’s functions for viscoelastic BISQ media are then derived based on the classic potential function methods. Our numerical results show that S-waves are only affected by viscoelasticity, but not by squirt-flows. However, the phase velocity and attenuation of fast P-waves are seriously influenced by both viscoelasticity and squirt-flows; and there exist two peaks in the attenuation-frequency variations of fast P-waves. In the low-frequency range, the squirt-flow characteristic length, not viscoelasticity, affects the phase velocity of slow P-waves, whereas it is opposite in the high-frequency range. As to the contribution of potential functions of two types of compressional waves to the Green’s function, the squirt-flow length has a small effect, and the effects of viscoelastic parameter are mainly in the higher frequency range.