Mesoscale metrics on approach to the clogging point

In this work we present results of the flow of monodisperse spheres in a two-dimensional silo. By taking high-speed video during the flow of grains, we are able to look at the microscopic dynamics of the individual grains. We report on how measures such as velocity fluctuations, non-affine motion, and dynamical heterogeneities change in as the system approaches clogging. While we do find changes in these metrics on approaching the clogging point, we do not see evidence to suggest that it is a critical point. We contrast the clogging transition with the jamming transition in light of these results. Graphic abstract