Numerical simulation of inelastic frictional spheres in simple shear flow

A numerical program is developed to simulate an assembly of inelastic frictional spheres inside a control volume undergoing rapid shearing motion induced by the top and bottom moving periodic boundaries. A sticking–sliding collision model is used to emulate binary collisions of real particles. After the flow has reached a steady state, ensemble averages of macroscopic properties such as translational and rotational granular temperatures, and kinetic and collisional stresses at different solids concentrations are obtained. The present results are compared with previous theoretical, numerical and experimental works, and favourable agreement is found among them. The simulation results show that the stresses are anisotropic and decrease with decreasing coefficient of restitution and increasing friction coefficient. At high solids fraction, above about 0.5, there exists a critical concentration where the layering effects of particles, the formation of high-density microstructures and the increase in correlation of particle velocities are the major causes of abrupt changes in flow properties.