(310e) Rheology and Segregation of Granular Mixtures In Dense Flow

We investigate the rheology of granular
mixtures, comprising particles of different size and density, in a
flow on a rough inclined plane by means of Discrete Element Method
(DEM) based simulations. Steady flows at relative high particle
volume fractions (f > 0.5)
are considered for different density ratios, size ratios and
inclination angles. A new model based on the viscoplastic model of
Jop et al. (Nature, 441,
727, 2006) is shown to describe the rheology of the mixtures quite
well. Segregation of particles is analyzed by considering the
sedimentation of single particles in the flow. We find that modified
versions of Stokes Law and Archimedes principle may be used to obtain
the drag force and buoyancy experienced by the sedimenting particle.
A continuum model is developed to predict the equilibrium segregation
in the flow and compared to simulation results.