3D hierarchical -FEM applied to elasto-acoustic modelling of layered porous media

This paper presents a 3-D hierarchical (p-version) finite element description of the solid displacement–fluid displacement form of Biotʹs equation for elasto-acoustic modelling of multiple-layered isotropic porous media. nvergence related to mesh refinement extensions for different orders of polynomial approximation is briefly discussed for a homogeneous foam. The highest computational efficiency for reasonable levels of the error in the low-frequency region was obtained for fourth-order polynomial finite element interpolations. The main focus is on coupling conditions and on the convergence of solutions to Biotʹs equations in cases with multiple layers having different material properties. Simulations of a two-layered porous material with low flow resistivity suggest slow convergence rate of the fluid displacement field close to the interface between the layers.