Dresden 2017 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
DY: Fachverband Dynamik und Statistische Physik
DY 31: Particulate Matter I: From microscopic interactions to collective motion (Focus session)
DY 31.7: Vortrag
Mittwoch, 22. März 2017, 11:45–12:00, ZEU 118
Outflow and clogging of shape-anisotropic grains in hoppers with small apertures — •Ahmed Ashour1, Tamás Börzsönyi2, and Ralf Stannarius1 — 1Institute of Experimental Physics, Otto von Guericke University, Magdeburg, Germany — 2Institute for Solid State Physics and Optics, Wigner Research Center for Physics, Hungarian Academy of Sciences, Budapest, Hungary
Outflow of granular material through a small orifice is a fundamental process in many industrial fields, for example in silo discharge, and in everyday's life. Most experimental studies of the dynamics have been performed so far with monodisperse disks in two-dimensional (2D) hoppers or spherical grains in 3D. We investigate this process for shape-anisotropic grains in 3D hoppers and discuss the influence of size and shape parameters on avalanche statistics, clogging states, and mean flow velocities. Increasing the aspect ratio of the grains leads to lower flow rates and higher clogging probabilities compared to spherical grains. The number of grains forming the clog is larger for elongated grains of comparable volumes, and the long axis of these blocking grains is preferentially aligned towards the center of the orifice. At still higher aspect ratio, the outflowing material leaves long vertical rat-holes in the hopper that can even reach the surface of the granular bed.