In freely cooling granular material, statistical fluctuations in density and temperature can cause position dependent energy loss. With the TC model, multi-particle contacts are defined as those collisions that involve particles which had already a collision no longer than a short time ago. The probability of cell occupancy is compared to the Poisson distribution for a homogeneous system.
Deviations are visible at the tails first and also the mean-value or the maximum are reduced.
More and more cells are filled with additional particles and on the other hand, for the reason of mass-conservation, other cells are emptied in return.