Granular flow in a rapidly rotated system with fixed walls.

The flow properties in a granular system confined by a rapidly rotated bottom surface and fixed walls are investigated. Above sufficiently high rotation rates the system enters a state in which the flow is independent of the driving rate. Further, a nearly constant shear-strain rate is measured throughout the entire system. Optical and particle imaging velocimetry methods are used to measure the surface flows, and large-scale molecular dynamics simulations are performed to model the flows both at the surface and in the interior of the material. The analysis shows a regime of granular flow in which shear banding is absent.