Mesoscopic length scale controls the rheology of dense suspensions.
From the flow properties of dense granular suspensions on an inclined plane, we identify a mesoscopic length scale strongly increasing with volume fraction. When the flowing layer height is larger than this length scale, a diverging Newtonian viscosity is determined. However, when the flowing layer height drops below this scale, we evidence a nonlocal effective viscosity, decreasing as a power law of the flow height. We establish a scaling relation between this mesoscopic length scale and the suspension viscosity. These results support recent theoretical and numerical results implying collective and clustered granular motion when the jamming point is approached from below.
Bonnoit
Claire
C
PMMH, ESPCI, CNRS (UMR 7636) and Université Paris 6 and Paris 7, 10 rue Vauquelin, 75005 Paris, France.
Lanuza
Jose
J
Lindner
Anke
A
Clement
Eric
E