Arching in three-dimensional clogging
1 Department of Theoretical Physics, Budapest University of Technology and Economics, H-1111 Budapest, Hungary
2 Institute for Solid State Physics and Optics, Wigner Research Center for Physics, Hungarian Academy of Sciences, PO Box 49, H-1525 Budapest, Hungary
3 Institute of Experimental Physics, Otto-von-Guericke-University, Universitatsplatz 2, D-39106 Magdeburg, Germany
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Published online: 30 June 2017
Arching in dry granular material is a long established concept, however it remains still an open question how three-dimensional orifices clog. We investigate by means of numerical simulations and experimental data how the outflow creates a blocked configuration of particles. We define the concave surface of the clogged dome by two independent methods (geometric and density based). The average shape of the cupola for spheres is almost a hemisphere but individual samples have large holes in the structure indicating a blocked state composed of two-dimensional force chains rather than three-dimensional objects. The force chain structure justifies this assumption. For long particles the clogged configurations display large variations, and in certain cases the empty region reaches a height of 5 hole diameters. These structures involve vertical walls consisting of horizontally placed stable stacking of particles.
© The Authors, published by EDP Sciences, 2017
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