2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/29005We formulate a phenomenological model for the segregation of binary mixtures of rough and smooth granular materials in a rotating drum. Our model successfully replicates a range of experimental behaviours, e.g., rapid radial segregation; slow axial segregation; and nonuniform radial structure of axial bands. We present some analytical results and detailed numerical results for our model.5 FiguresCondensed Mattertext