Abstract
Granular flows driven by gravity on steep inclines observed in nature often show inverse grading, characterized by the presence of the large grains near the free surface and smaller grains near the bottom. We use kinetic theory, simplified by the hypothesis of dense flow, to investigate the parameters governing the segregation process in binary mixtures composed of nearly elastic spheres that differ in size and mass density. We derive the equation that can be solved in order to study the time and space evolution of the concentration of the two species under the hypothesis that one species is dilute and the other is dense.