title: Rheology of a sonofluidized granular packing.
abstract: We report experimental measurements on the rheology of a dry granular material under a weak level of vibration generated by sound injection. First, we measure the drag force exerted on a wire moving in the bulk. We show that when the driving vibration energy is increased, the effective rheology changes drastically: going from a non-linear dynamical friction behavior --weakly increasing with the velocity-- up to a linear force-velocity regime. We present a simple heuristic model to account for the vanishing of the stress dynamical threshold at a finite vibration intensity and the onset of a linear force-velocity behavior. Second, we measure the drag force on spherical intruders when the dragging velocity, the vibration energy, and the diameters are varied. We evidence a so-called "geometrical hardening" effect for smaller-size intruders and a logarithmic hardening effect for the velocity dependence. We show that this last effect is only weakly dependent on the vibration intensity.
authors.affiliation: Centro de Investigación en Materiales Avanzados S.C., Nuevo León, México. gabriel.caballero@cimav.edu.mx
authors.forename: G A
authors.initials: GA
authors.lastname: Caballero-Robledo
authors.forename: E
authors.initials: E
authors.lastname: Clément