Internal avalanches and restructuring in granular media

We study the phenomenon of internal avalanching within the context of recently proposed “Tetris” lattice models for granular media. We consider a packing of particles subjected to two different dynamics. In the first case, we arrest the system at different instances during an “aging” dynamics during which the packing slowly compactifies under shaking, and study the distribution of internal avalanches at each of these instances. In the second case, we define a recycling dynamics under which the system reaches a steady state under continued avalanching. We study the distribution of avalanches in this steady state. In the former case we investigate numerically the effect of the density of the medium on the avalanche distribution. In the latter case we develop a mean-field theory to help understand the reciprocal effect of the avalanches on the medium.