Dense, rapid flows of inelastic grains under gravity.

The standard hydrodynamic description does not apply to the rapid flow regime of inelastic grains in the dense limit. Emphasizing the role of inelastic loss and collapse, we propose a new approach relying on a nonlocal dissipation scheme. Our model succeeds in accounting qualitatively and quantitatively for the linear profile of velocity found in experiments on dense gravity-driven flows.