Shearing behavior of polydisperse media.

We study the shearing of polydisperse and bidisperse media with a size ratio of 10. Simulations are performed with a two-dimensional shear cell using contact dynamics. With a truncated power law for the polydisperse media we find that they show a stronger dilatancy and greater resistance to shearing than bidisperse mixtures. To model additives used to control viscosity we introduce so-called "point-like particles". Even changing the kinematic behavior very little, the point-like particles reduce the force necessary to maintain a fixed shearing velocity.