Numerical investigation of unsteady state hopper flow

This paper presents a numerical study of the unsteady state granular flow in a cylindrical hopper with flat bottom by means of the discrete element method. The distributions of the physical properties including velocity, force and stress are investigated qualitatively or quantitatively. It is shown that this flow has four different flow zones, in which these distributions are different. At different discharging times, the trends of the characteristics are similar, but their magnitudes different. The results also show that the trends of the unsteady and steady state hopper flows in terms of velocity, force and stress are similar. But, quantitatively, there are differences in these physical properties for the two flows.