ABSORBING BOUNDARY-CONDITIONS FOR DYNAMIC ANALYSIS OF FLUID-SATURATEDPOROUS-MEDIA

Based on Biot's two-phase mixture theory and the paraxial approximatio n, the absorbing boundary conditions in the time domain for u-w, u-U a nd u-p formulations are presented for the dynamic analysis of fluid-sa turated porous media. These absorbing boundaries are equivalent to the viscous boundaries in the fundamental mode. The expressions for the e nergy ratio and reflection coefficient between the reflected and incid ent waves along the absorbing boundary are given. The numerical result s show that the proposed absorbing boundaries can greatly suppress the spuriously reflected wave and model the far field of the system. Thes e results also demonstrate the accuracy and efficiency of the proposed method for the transient dynamic analysis of infinite fluid-saturated porous media.