Rheology and Segregation in Dense Sheared Granular Flows

Particles in motion tend to segregate by particle properties such as size, density and shape. When particle-scale segregation mechanisms (e.g., gravity and shear rate gradients) combine with system-wide advection they give rise to a wide variety of large scale segregation patterns. In and of itself, segregation phenomenology can be fascinating. Additionally, the presence of segregation patterns can significantly influence flow behaviors in granular materials as the local and global rheologies vary with the local and global concentrations. Understanding these phenomena is important for a wide range of granular flows that help shape the earth surface including rocky debris flows and sediment transport in rivers. This presentation will describe small-scale experiments and simulations we use to develop models for the interdependence between segregation and rheology in relatively simple sheared granular flows.