Diffusion as a mixing mechanism in granular materials - art. no. 011304

We present several numerical results on granular mixtures. In particular, w e examine the efficiency of diffusion as a mixing mechanism in these system s. The collisions are inelastic and to compensate the energy loss, we therm alize the grains by adding a random force. Starting with a segregated syste m, we show that uniform agitation (heating) leads to a uniform mixture of g rains of different sizes. We define a characteristic mixing time tau (mix), and study theoretically and numerically its dependence on other parameters like the density. We examine a model for bidisperse systems for which we c an calculate some physical quantities. We also examine the effect of a temp erature gradient and demonstrate the appearance of an expected segregation.