Title: Granular Flow within a Quasi-2D Hopper in the Presence of Symmetrical and Asymmetrical Angled Orifice Boundaries

Author (Table Talk): Levi Cass, College of the Holy Cross

Abstract:

Granular flow in quasi-2D silos, in the typical configuration of symmetric bottom boundaries, has been studied extensively in both experiments and simulations, and modeled by applying the work-energy theorem to these dense flows [1]. A recent experiment [2] extended the application of this model to tilted silos, where the orifice is no longer aligned with gravity, by considering the velocity of grains along side streams based on angles imposed by grain properties (the stagnant zone angle) and boundaries (the tilted condition). We now present experiments aimed at testing this model further by applying, for vertical silos, asymmetric bottom-boundary angles to modify the side stream flow of grains. We measure the mass flow rate of a quasi-2D monodisperse granular material from a vertical silo with ten different boundary conditions. Our preliminary findings show that flow rates increase for steeper symmetric boundary angles and, interestingly, suggest that flow rates in the asymmetric case where one side of the silo is flat (regardless of the other sides angle) are not significantly different from the completely flat-bottomed case. Next steps will include streamlining data collection and analysis at higher precision to acquire better statistics of mass flow rates as a function of angled boundary conditions. Madrid, et. al. EPL. 123, 14004 (2018). Kozlowski, et. al. Granular Matter. 25, 19 (2023).