- Two-dimensional physical and numerical models for predicting the characteristics of the flowfield during an unsteady interaction between a planar shock wave moving through air and a deformable saturated porous material were developed using the representative-elementary-volume approach. The numerical model is based on a two-phase arbitrary Lagrangian Eulerian finite difference scheme to solve the flowfield governing equations. The multidimensional effects of the, head-on collision were investigated. The physical model is validated by comparing the numerical predictions qualitatively and quantitatively to one- and two-dimensional shock-foam interaction experimental results. Good agreement was obtained both in one-and two-dimensional cases. It was found that wall friction results in shear bands (i.e., localized. high vorticity), which affects the flowfield characteristics. Therefore, the common one-dimensional models are not valid in the vicinity of the shock tube sidewalls.