How fluid-mechanical erosion creates anisotropic porous media

Using a Cauchy integral formulation of the boundary equations, we simulate erosion porous medium comprised up to 100 solid bodies embedded in two-dimensional Stokes flow. The grains are resolved individually and erode under action surface shear stress. Through nonlinear feedback with surrounding flow fields, microscopic changes grain morphology give way larger-scale features such as channelization. Cauchy-integral associated quadrature formulas enable us resolve dense configurations nearly contacting bodies. We observe substantial anisotropy develop over course erosion; that is, result from generally permit longitudinal direction more easily than transverse by factor six. These results suggest material groundwater flows may contribute previously observed natural media.