4 research outputs found
Rheology of Weakly Vibrated Granular Media
We probe the rheology of weakly vibrated granular flows as function of flow
rate, vibration strength and pressure by performing experiments in a vertically
vibrated split-bottom shear cell. For slow flows, we establish the existence of
a novel vibration dominated granular flow regime, where the driving stresses
smoothly vanish as the driving rate is diminished. We distinguish three
qualitatively different vibration dominated rheologies, most strikingly a
regime where the shear stresses no longer are proportional to the pressure.Comment: 14 pages, 19 figures, submitted to PR
Anisotropy of weakly vibrated granular flows
We experimentally probe the anisotropy of the fabric of weakly vibrated,
flowing granular media. Depending on the driving parameters --- flow rate and
vibration strength --- this anisotropy varies significantly. We show how the
anisotropy collapses when plotted as function of the driving stresses,
uncovering a direct link between stresses and anisotropy. Moreover, our data
suggests that for small anisotropies, the shear stresses vanish. Anisotropy of
the fabric of granular media thus plays a crucial role in determining the
rheology of granular flows