Molecular-dynamics simulations of granular axial segregation in a rotating cylinder

In order to investigate segregation of granular binary-mixtures in a horizontally rotating cylinder, three-dimensional molecular dynamics simulations are carried out. Two kinds of particles, which have different diameters and/or different roughness of surfaces, are segregated into three bands. It is found that particles receive averaged force cohesively at the boundaries of segregated bands. The present analysis shows that segregated narrow bands are formed by diffusion process and that the cohesive forces operating at the boundaries stabilize them.