Simulations of arch formation in hopper flows of soft spherical particles

The flow of soft particles is observed in a variety of systems, from pressure-driven suspension flows in microfluidic channels to gravity-driven flows of granular materials in silos and hoppers. In these systems, flow-induced jamming (or clogging) can occur when collections of particles flow into a confined region and those particles jam before exiting the region. Clogging occurs in particulate materials over a wide range of particle sizes, shapes, and interactions, as well as driving and boundary conditions. During a clogging event, particles collect at the hopper opening, forming an arch and preventing outflow. Understanding the mechanical properties of arches is necessary to develop a predictive model for the flow and clogging behavior of soft particles. We carry out soft-particle simulations of hopper flows for a range of orifice widths and driving forces. To quantify the clogging behavior, we characterize arch formation by measuring the size and shape of the arches, as well as the particle dynamics leading up to a clogging event.