Pattern Scaling in Axial Segregation

Axial segregation in a cylindrical centrifuge.

We propose a theory for axial segregation of suspensions of non-neutrally buoyant particles in a rotating cylinder. The cylinder is oriented in the horizontal plane, so that any axial forces must arise from interparticle interactions. We show that the hydrodynamic interaction between pairs of particles produces a relative motion in the axial direction, independent of the gravitational force. If...

Reversible axial segregation of rotating granular media.

Scaling behaviour in size segregation (”Brazil Nuts”)

2014 Using a previously introduced Monte Carlo method, due to Rosato, Prinz, Strandburg and Swendsen, we carry out in two dimensions numerical studies of size segregation, a phenomenon which occurs when a granular medium made of particles of different sizes is shaken. We propose a new scaling law relating the segregation velocity 03C5 to the amplitude of shaking A and to the ratio R of the diam...

Axial segregation of a settling suspension in a rotating cylinder.

A rotating suspension of nonbuoyant particles can develop striking inhomogeneities in particle concentration, with regular bands of high and low concentration along the symmetry axis. We report Stokes-flow simulations showing that the formation of axial bands is correlated with an inhomogeneous particle distribution in the radial plane. An order parameter, based on the average angular velocity ...

Continuum theory of axial segregation in a long rotating drum.

We develop a continuum description for the axial segregation of granular materials in a long rotating drum based on the dynamics of the thin near-surface granular flow coupled to bulk flow. The equations of motion are reduced to the one-dimensional system for two local variables only, the concentration difference and the dynamic angle of repose, or the average slope of the free surface. The par...