Abstract: In this paper, the time-domain boundary element method is employed to investigate transient fluid-structure interaction problems in porous elastic media. The proposed method automatically satisfies the far-field boundary condition at infinity, thus only necessitating boundary discretization, which renders it particularly well-suited for addressing problems characterized by infinite boundaries. Initially, the boundary integral equation for the transient fluid-structure interaction problem is derived from the governing partial differential equations that describe porous elastic media. Subsequently, numerical discretization is applied to the boundary integral equation, with a particular focus on accurately computing the Hadamard principal value of the element influence coefficients that exhibit strong singularities. This strategy effectively circumvents error accumulation in indirect numerical schemes and improves computational precision. Following this, second-order shape functions are adopted to determine the influence coefficients of semi-infinite elements, and the algebraic system corresponding to the boundary integral equation is constructed through assembly. Two representative numerical examples are used for validation purposes, wherein the numerical results generated by the proposed method are compared with analytical solutions. The results substantiate that the developed time-domain boundary element method is both applicable and reliable for solving transient fluid-structure interaction problems in porous elastic media.

Key words: porous elastic medium, transient fluid-structure coupling, time domain boundary element method, treatment of singularities, infinite domain