Dresden 2017 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 31: Particulate Matter I: From microscopic interactions to collective motion (Focus session)

DY 31.9: Talk

Wednesday, March 22, 2017, 12:15–12:30, ZEU 118

The effect of particle shape on the flow field in a quasi-2D hopper — •Balázs Szabó¹, Zsolt Kovács¹, Sandra Wegner², Ahmed Ashour², David Fischer², Ralf Stannarius², and Tamás Börzsönyi¹ — ¹Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, Hungary — ²Otto-von-Guericke-University, D-39106 Magdeburg, Germany

We study the outflow and the clogged states of spherical and nonspherical particles in a quasi-2D hopper setup by means of optical measurements. For spherical grains, the vertical velocity profile along a horizontal line is close to Gaussian, as suggested by most of the existing theories. However, for prolate particles, this curve clearly deviates from a Gaussian profile, indicating that the alignment of the grains has a strong effect on the velocity field. The plug-like flow profile suggests a fitting function that is the sum of two error functions, with two characteristic length scales instead of one. One parameter is the displacement of the two error functions, which appears to be related to the geometry of the setup. The other parameter is the width of the error functions, which is more sensitive to the particle shape.