Drag force in immersed granular materials

Dynamics of crater formations in immersed granular materials.

We report the formation of a crater at the free surface of an immersed granular bed, locally crossed by an ascending gas flow. In two dimensions, the crater consists of two piles which develop around the location of the gas emission. We observe that the typical size of the crater increases logarithmically with time, independently of the gas emission dynamics. We describe the related granular fl...

Depth-Independent Drag Force Induced by Stirring in Granular Media

Leaching models for multiple immersed materials and for granular materials flushed in a column

The present paper addresses the leaching of hazardous contaminants from immersed and replenished materials and from granular materials flushed in a column. First, the leaching of an immersed material in contact with a limited volume of leachant is studied. The mass transfer from material to leachant is assumed to he inversely proportional to Jt (i.e. following the semiinfinite medium diffusion ...

Tail of the contact force distribution in static granular materials.

We numerically study the distribution P(f) of contact forces in frictionless bead packs, by averaging over the ensemble of all possible force network configurations. We resort to umbrella sampling to resolve the asymptotic decay of P(f) for large f , and determine P(f) down to values of order 10{-45} for ordered and disordered systems in two (2D) and three dimensions (3D). Our findings unambigu...

Green’s Function Measurements of Force Transmission in 2D Granular Materials

We describe experiments that probe the response to a point force of 2D granular systems under a variety of conditions. Using photoelastic particles to determine forces at the grain scale, we obtain ensembles of responses for the following particle types, packing geometries and conditions: monodisperse ordered hexagonal packings of disks, bidisperse packings of disks with different amount of dis...