Granular erosion in Stokes flow

Fluid-mechanical erosion of solid material occurs across many scales, from massive geological structures down to tiny granular constituents. Here, we numerically examine the erosion of a granular medium in the Stokes limit — the regime of groundwater flow. We combine a highly accurate boundary-integral formulation of the Stokes equations with stable interface-evolution methods. A single body erodes into a slender, for-aft-symmetric morphology which can be described analytical. Using the fast multipole method allows the simulation of 10-100 bodies. Many-body erosion naturally leads to the formation of channels and anisotropy in the medium
conductivity.