Surface flows of granular mixtures - III. Canonical model

We present the generalization of the minimal model fur surface flows of gra nular mixtures proposed by Boutreux and de Gennes [J. Phys. I France 6, 129 5 (1996)]. The minimal model was valid for grains differing only in their s urface properties. The present model also takes into account differences in thr: sire of the grains. We apply the model to study segregation in two-di mensional silos of mixtures of grains differing in size and/or surface prop erties. When the difference in size is small, the model predicts that a con tinuous segregation appears in the static phase during the filling of a sil o. When the difference in size is wide, we take into account the segregatio n of the grains in the rolling phase, and the model predicts complete segre gation and stratification in agreement with experimental observations.