Hysteresis in granular media subjected to axisymmetrical rotation

In this work we have studied the hysteretic behavior for the mean slope of the free surface of noncohesive granular media under axisymmetrical rotation. In order to study the hysteresis loop the relationship between the average slope of the free surface (most important measurable quantity) and the Froude number has been established. Differences between experiments and theoretical predictions are also shown. Theory predicts that hysteresis must disappear as the friction coefficient μ of the granular material reaches unity. However, this condition could not be reached experimentally using tapioca (where μ ∼ 1), due to the important difference between the angle of internal friction and the angle of repose for small containers.