Statistics of void sizes and avalanche signatures in a slowly-driven open-sided granular pile

Abstract

Using image processing of video frames, we obtained the statistical distribution of avalanche sizes in a slowly driven pile of sago grains. Avalanches that form by slowly adding grains to a pile in a 61.00 cm × 152.3 cm container at a rate of 1/3 Hz are captured in a 30 fps video, which are then analyzed frame by frame. The voids between grains at any given frame show two characteristic values (modes), wherein the first one corresponds to the void size in a stable configuration of sago grains, and the second one corresponds to the dynamic part of the pile where avalanches are formed. Insights from the experiment may be used to detect the occurrence of avalanches in the granular setup.