DECOMPACTION MODES OF A 2-DIMENSIONAL SANDPILE UNDER VIBRATION - MODEL AND EXPERIMENTS

We report a series of experiments dealing with the progressive decompaction of a bidimensional pile of aluminum beads under vibration. We put forward a model that allows one to understand that the bulk decompaction originates from interaction between the lateral walls of the container and the beads. The conjugated role of the local geometry of the array, the solid friction, and the aspect ratio of the pile is established. A single dimensionless parameter is introduced, which, besides the acceleration, characterizes the decompacted state. This parameter is determined independently and consistently throughout several different experiments.