Dresden 2011 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 1: Focus Session: Dense Granular Flow
DY 1.2: Invited Talk
Monday, March 14, 2011, 10:45–11:15, HÜL 186
Shear localization and shear alignment in granular flows — •Tamás Börzsönyi1, Balázs Szabó1, Gábor Törös1, Jim N. McElwaine2, Robert E. Ecke3, Sandra Wegner4, and Ralf Stannarius4 — 1Research Institute for Solid State Physics and Optics, P.O. Box 49, H-1525 Budapest, Hungary — 2Department of Applied Mathematics and Theoretical Physics, University of Cambridge, UK — 3CNLS, Los Alamos National Laboratory, Los Alamos, NM 87545, USA — 4Otto-von-Guericke-University, Institute of Experimental Physics, Universitätsplatz 2, D-39106 Magdeburg, Germany
Dense granular flows have been investigated experimentally and numerically in various geometries. For inclined plane flows we determine how the flow density decreases with increasing shear rate and also show, that the effective friction changes non-monotonously with increasing shear rate. This leads to a flow instability and shear localization. An other phenomenon is, that elongated grains get aligned in a simple shear flow. We study this flow alignment at low shear rates and find, that the alignment angle is independent of the shear rate, which is very similar to the flow alignment of liquid crystals. The shear induced orientation leads to a reduction of the effective friction of the material, which we determine experimentally.
T. Börzsönyi, R.E. Ecke and J.N. McElwaine, Phys. Rev. Lett. 103, 178302 (2009)