Velocity profiles of granular materials during the drainage of a hopper

ULISSI FACUNDO, IPPOLITO IRENE, CALVO ADRIANA, MARTORELLO LEANDRO, GALLIANO PABLO

Orsay

Workshop; Traffic and Granular Flow 2007; 2007

  We analyse the flow of granular materials inside a quasi-two-dimensional silo as it drains and compare the datawith some existingmodels. The particle flows inside the silo are recorded and analysed by PIV (Particle Image Velocimetry) in both space and time to obtain their velocity profile. Grains used in the experiments are: sand river grains, glass beads and quartz grains with irregular geometry. The data obtained by varying the hopper angle and the grain geometry and size allow us to understand driven flows inside these geometries. On the other hand, we study the influence of the rougness of the lateral walls on the velocty profiles. We have chosen the geometrical parameters of the silo (aperture angle, width orifice)  in order to perform the experiments in a continuous flow regime. During the drainage, we find that the mean velocity profile can vary from gaussian to a plug profile depending on the position of the free surface of the packing in motion. Finally, we discuss the flow rate as a function of the orifice width and hopper angles.