Flow dynamics of granular materials in a hopper.

Jamming of Granular Flow in a Two-Dimensional Hopper.

We study experimentally the jamming phenomenon of granular flow of monodisperse disks of D = 5 mm diameter in a two-dimensional hopper with opening R. The jamming probability J(d) is measured where d identical withR/D. We found that J(d) decreases from 1 to zero when d increases from 2 to 5. From observing the disk configurations of the arch in the jamming events, the jamming probability can be...

Response to perturbations for granular flow in a hopper.

We experimentally investigate the response to perturbations of circular symmetry for dense granular flow inside a three-dimensional right-conical hopper. These experiments consist of particle tracking velocimetry for the flow at the outer boundary of the hopper. We are able to test commonly used constitutive relations and observe granular flow phenomena that we can model numerically. Unperturbe...

Effects of horizontal vibration on hopper flows of granular materials

This study experimentally examines the flow of glass spheres in a wedgeshaped hopper that is vibrated horizontally. When the hopper is discharged without vibration, discharge occurs as a hnnel flow, with the material exiting the central region of the hopper and stagnant material along the sides. With vibration, the discharge of the material occurs in reverse, with the material along the sides e...

Flow of wet granular materials.

The transition from frictional to lubricated flows of a dense suspension of non-Brownian particles is studied. The pertinent parameter characterizing this transition is the Leighton number Le=eta(s)gamma / sigma, the ratio of lubrication to frictional forces. Le defines a critical shear rate below which no steady flow without localization exists. In the frictional regime the shear flow is local...

Dynamics of levitated granular materials