Gravity-driven dense granular flows

We report and analyze the results of numerical studies of dense granular fl ows on an incline with a rough bottom in two and three dimensions, using li near damped spring or Hertzian force laws between particles with a Coulomb failure criterion. This ow geometry produces a constant density pro le that satis es 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 di er 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.