Gravity-driven dense granular flows

We report and analyze the results of numerical studies of dense granular flows on an incline with a "rough" bottom in two and three dimensions, using linear damped spring or Hertzian force laws between particles with a Coulomb failure criterion. This flow geometry produces a constant density profile that satisfies scaling relations of the Bagnold, rather than viscous, kind. The type of force law has little impact on the behavior of the system. The bulk and the surface layer differ in their rheology, as evidenced by the change in principal stress directions near the surface. Surface-only flows are not observed for the cases studied.