Granular avalanches in fluids.
Three regimes of granular avalanches in fluids are put in light depending on the Stokes number St which prescribes the relative importance of grain inertia and fluid viscous effects and on the grain/fluid density ratio r. In gas (r>>1 and St>1, e.g., the dry case), the amplitude and time duration of avalanches do not depend on any fluid effect. In liquids (r approximately 1), for decreasing St, the amplitude decreases and the time duration increases, exploring an inertial regime and a viscous regime. These three regimes are described by the analysis of the elementary motion of one grain.
Courrech Du Pont
Sylvain
S
Laboratoire Fluides, Automatique, Systèmes Thermiques, Bâtiment 502, Campus Universitaire, 91405 Orsay cedex, France.
Gondret
Philippe
P
Perrin
Bernard
B
Rabaud
Marc
M