Continuum modelling of primary and secondary granular flows in a torsional shear cell

摘要: Abstract In granular flows, the particles not only move along principal streamlines but can also circulate perpendicularly to slowly in a vortex-like manner. Such behaviours have both scientific and practical significances, e.g. convective mixing of particles, their mechanisms are still under study. Previous experimental observations stimulated two explanations for them: centrifugal force volumetric dilatancy. Here theoretical model is constructed test these conjectures, which based on frictional plasticity accounts dynamic effect strain-dependent The simulation results show that, influence gravity, indeed give rise vortices Couette cell. absence force, be observed depending shape yield surface. If surface von Mises circle deviatoric plane, i.e. Drucker-Prager type, no vortex continuum modelling. But noncircular surfaces, clear secondary flow generated at some boundary conditions increases magnitude with non-circularity Large dilatancy occurs regimes high gradients, altogether its critical. role discussed.