Jamming of granular flow in a two-dimensional hopper

Experiments were performed to account for the jamming phenomenon of the granular system of monodisperse disks in two-dimensional (2D) hoppers. When the arch at the hopper opening was considered as a trajectory of a restricted self-avoiding random walker and the statistics of the number of disks in the arch were measured, the observed jamming probabilities were accounted for quantitatively when the hopper angle is less than 75°.