Regensburg 2022 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 11: Granular Matter and Contact Dynamics

DY 11.5: Vortrag

Montag, 5. September 2022, 16:30–16:45, H19

The role of the particle aspect ratio in the discharge of a narrow silo — •Bo Fan^2,4, Tivadar Pongó^1,2, Dariel Hernández-Delfin^1,5, János Török³, Ralf Stannarius⁶, Raúl Cruz-Hidalgo¹, and Tamás Börzsönyi² — ¹Universidad de Navarra, Pamplona, Spain — ²Wigner Research Centre for Physics, Budapest, Hungary — ³Budapest University of Technology and Economics, Budapest, Hungary — ⁴Wageningen University, Wageningen, The Netherlands — ⁵Basque Center for Applied Mathematics, Bilbao, Spain — ⁶Otto von Guericke University, Magdeburg, Germany

The time evolution of silo discharge is investigated for different granular materials made of spherical or elongated grains in laboratory experiments and with discrete element model (DEM) calculations. For spherical grains, we confirm the widely known typical behavior with constant discharge rate (except for initial and final transients). For elongated particles with aspect ratios between 2 < L/d < 6.1, we find a peculiar flow rate increase for larger orifices, especially in the last third of the discharge process. While the flow field is practically homogeneous for spherical grains, it has strong gradients for elongated particles with a fast-flowing region in the middle of the silo surrounded by a stagnant zone. For large enough orifice sizes, the flow rate increase is connected to a gradual change in the character of the flow field, including a shrinkage of the stagnant zone and an increase in both the packing fraction and flow velocity near the silo outlet.