Heaping, Secondary Flows and Broken Symmetry in Flows of Elongated Granular Particles

Abstract

In this paper we report experiments where we shear granular rods in split-bottom geometries, and find that a significant heap of height of least 40% of the filling height can form at the particle surface. We show that heaping is caused by a significant secondary flow, absent for spherical particles. Flow reversal transiently reverses the secondary flow, leading to a quick collapse and slower regeneration of the heap. We present a symmetry argument and experimental data that show that the generation of the secondary flow is driven by a misalignment of the mean particle orientation with the streamlines of the flow. This general mechanism is expected to be important in all flows of sufficiently anisometric grains.

Accepted for Soft Matter

References in corpus (4)

• Effects of grain shape on packing and dilatancy of sheared granular materials
• Shear zones in granular media: 3D Contact Dynamics simulation
• MR Imaging of Reynolds Dilatancy in the Bulk of Smooth Granular Flows
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Cited by in corpus (6)

• Packing, alignment and flow of shape-anisotropic grains in a 3D silo experiment
• Flow and rheology of frictional elongated grains
• Secondary flow in ensembles of non-convex granular particles under shear
• Evolution of shear zones in granular packings under pressure
• Transverse vortices induced by modulated granular shear flows of elongated particles
• Convective Flows in Sheared Packings of Spherical Particles