Free-surface granular flows down heaps (Q2479848)

The paper extends the slow, high-concentration, strain rate fluctuation theory for disk-like particles (for quasi-static and collisional stresses) to treat three-dimensional spherical particles. The quasi-static contributions arise from the strain-rate fluctuations embodied in the critical-state plasticity model. In the present paper the governing equations account for the effects of long-term frictional contacts. The equations shows flows that range from the slow, quasi-static regime to the rapid, collisional, grain-inertia flow regime. Simple shear flows are analyzed. The equations are integrated to obtain deep profiles of mean velocity, granular temperature, solid fraction and Savage-Jeffrey parameter. A detailed comparison with experimental data shows good agreement which is, however, not perfect.