Radial segregation patterns in rotating granular mixtures: Waviness selection

The radial segregation patterns that form in a thin rotating drum partially filled with beads of two sizes were modeled. In the study, as soon as a moon pattern forms, it is subjected to waviness amplification and low-pass filtering. It was suggested that the waviness of a pattern should be subjected to low-pass filtering with a cutoff waviness that depends strongly on the fill level of the drum. It was also suggested that the filtering depends only on the geometry of the patterns and remains independent of the segregation mechanisms that operate in the flowing layer.