Dry and wet granular shock waves.

Codalike multiple scattering of elastic waves in dense granular media.

We study the multiple scattering of short-wavelength ultrasound through the force networks in dry and wet glass bead packings under stress. Over long distance scales, the diffusion approximation is shown to describe adequately the transport of elastic waves dominated by shear waves. The recovered transport mean path reveals a short-range correlation of the force chains. Also we observe the dras...

On Time Scales and Rheology of Dry and Wet Granular Materials

This paper results from an ongoing investigation of the rheology of dry and wet granular materials. We describe the different time scales involved and the related dimensionless numbers that govern dry as well as wet granular flows, with a focus to the dimensionless numbers relevant for flow in the quasistatic wet system at low confining stress. The macroscopic friction coefficient and the appar...

Mixing Behaviors of Wet Granular Materials in Gas Fluidized Beds

The mixing behaviors of dry and wet granular materials in gas fluidized bed systems were investigated computationally using the combined Computational Fluid Dynamics and Discrete Element Method (CFD-DEM). Dry particles were observed to mix fairly rapidly during the fluidization process due to vigorous relative motions between particles induced by the flow of gas. In contrast, due to the presenc...

Surface instabilities in shock loaded granular media

The initiation and growth of instabilities in granular materials loaded by air shock waves are investigated via shock-tube experiments and numerical calculations. Three types of granular media, dry sand, water-saturated sand and a granular solid comprising PTFE spheres were experimentally investigated by air shock loading slugs of these materials in a transparent shock tube. Under all shock pre...

Stability, Avalanches, and Flow in Dry and Wet Granular Materials