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Granular flow in a wedge-shaped heap: Velocity field,kinematic scalings,and segregation |
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| Authors: | Austin B. Isner Paul B. Umbanhowar Julio M. Ottino Richard M. Lueptow |
| Affiliation: | 1. Department of Chemical & Biological Engineering, Northwestern University, Evanston, Illinois;2. Department of Mechanical Engineering, Northwestern University, Evanston, Illinois;3. Department of Chemical & Biological Engineering, Northwestern University, Evanston, Illinois Department of Mechanical Engineering, Northwestern University, Evanston, Illinois Northwestern Institute on Complex Systems (NICO), Northwestern University, Evanston, Illinois |
| Abstract: | Free surface granular flows in bounded axisymmetric geometries are poorly understood. Here, we consider the kinematics and segregation of size-bidisperse flow in a rising conical heap by characterizing the flow of particles in a wedge-shaped silo with frictional sidewalls using experiments and discrete-element-method simulations. We find that the streamwise velocity is largest at the wedge centerline and decreases near the sidewalls, and that velocity profiles in the depthwise and spanwise directions are self-similar. For segregating size bidisperse mixtures, the boundary between small and large particles deposited on the heap is significantly further upstream at the sidewalls than at the centerline, indicating that measurements taken at transparent sidewalls of quasi-2D or wedge-shaped heaps are unrepresentative of an axisymmetric heap. The streamwise velocity and flowing layer depth locally satisfy the scaling relation of Jop et al (J Fluid Mech. 2005;541:167-192) when modified to account for the wedge geometry, highlighting the influence of wall friction on the flow. |
| Keywords: | conical heap discrete element method granular flow segregating flow |