Friction of a slider on a granular layer: Nonmonotonic thickness dependence and effect of boundary conditions
Abstract
We investigate the effective friction encountered by a mass sliding on a granular layer as a function of bed thickness and boundary roughness conditions. The observed friction has minima for a small number of layers before it increases and saturates to a value that depends on the roughness of the sliding surface. We use an index-matched interstitial liquid to probe the internal motion of the grains with fluorescence imaging in a regime where the liquid has no significant effect on the measured friction. The shear profiles obtained as a function of depth show a decrease in slip near the sliding surface as the layer thickness is increased. We propose that the friction depends on the degree of grain confinement relative to the sliding surfaces.
- Publication:
-
Physical Review E
- Pub Date:
- January 2006
- DOI:
- 10.1103/PhysRevE.73.010301
- arXiv:
- arXiv:cond-mat/0512575
- Bibcode:
- 2006PhRvE..73a0301S
- Keywords:
-
- 45.70.Ht;
- 45.70.Mg;
- Avalanches;
- Granular flow: mixing segregation and stratification;
- Condensed Matter - Soft Condensed Matter
- E-Print:
- 4 pages, 6 figures