Axisymmetrical rotation of a sand heap

This work is a phenomenological attempt to predict the dynamical response of a sand heap due to rotation about its vertical axis. We have attempted experiments and we developed a model in order to describe the effect of the rotation on the pile’s surface from a dimensionless force balance equation using Coulomb’s law. We obtained good agreement between the experimental patterns and the theory, depending on the material through the solid friction angle, and we gave a plausible mechanism for the way in which the history of the pile is determined by dynamical (Froude number) and material (friction coefficient) parameters.