Shear Profiles and Velocity Distribution in Dense Shear Granular Flow

We perform DEM simulations to investigate the influence of the packing fraction γ on the shape of mean tangential velocity profile in a 2D annular dense shear granular flow. There is a critical packing fraction γ_c. For γ<γ_c, the mean tangential velocity profile shows a roughly exponential decay from the shearing boundary and is almost invariant to the imposed shear rate. However, for γ>γ_c, the tangential velocity profile exhibits a rate-dependence feature and changes from linear to nonlinear gradually with the increasing shear rate. Furthermore, the distributions of normalized tangential velocities at differentpositions along radial direction exhibit the Gaussian or the composite Gaussian distributing features.