Heaping, secondary flows and broken symmetry in flows of elongated granular particles. Issue 13 (13th February 2015)

• Record Type: Journal Article
• Authors: Wortel, Geert; Börzsönyi, Tamás; Somfai, Ellák; Wegner, Sandra; Szabó, Balázs; Stannarius, Ralf; van Hecke, Martin
• Is Part Of: Soft matter. Volume 11:Issue 13(2015)
• Page Start: 2570
• Page End: 2576
• Publication Date: 2015-02-13
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c4sm02534b
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : In this paper we present the first evidence that flows of anisometric grains generate strong secondary flows. 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.