Simulations of two dimensional hopper flow

We report on discrete element simulations of the flow out of a hopper. The geometry of the setup, as well as the material parameters, are taken directly from the experiments reported by Tang and Behringer (Chaos 21:041107, 2011; IFRPI-NSF collaboratory: 2D hopper data summary, 2010). The simulations consider flow of elastic, frictional, disk-like particles as the slope of the hopper walls and the size of the opening are varied, so that we can consider both the regime where jamming happens frequently (small openings) and where it occurs very rarely, or not at all (large openings), as well as the influence of the slope of hopper walls. We discuss the distribution of jamming events, the mass flux out of the hopper, and the influence of material parameters on these quantities. In addition, we consider velocity and pressure fields in the hopper, as well as their fluctuations.