O. Pouliquen et R. Gutfraind, STRESS FLUCTUATIONS AND SHEAR ZONES IN QUASI-STATIC GRANULAR CHUTE FLOWS, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 53(1), 1996, pp. 552-561
Experimental investigations of quasistatic flows of a two-dimensional
granular material comprised of circular cylindrical rods are described
. The flows are confined by two rough, parallel walls that can be incl
ined to the vertical direction. It is observed that boundary layers de
velop next to the sidewalls and are approximately 5 particle diam. thi
ck, regardless of the width of the channel. The flows are analyzed by
means of a modification of Coulomb theory that takes into account stre
ss fluctuations that arise as a result of the ''granularity'' of the f
lowing material. We propose a probabilistic model where the stress flu
ctuations play the role of temperature, and the difference between the
shear stress and yield stress plays the role of an energy barrier tha
t the system has to overcome in order to yield. The velocity profiles
predicted by the model are in agreement with the experiments for both
vertical and inclined bins.