Experimental study of a 3D dry granular medium submitted to horizontal shaking

Abstract

International audienceThis experimental work consists in a study of the influence of horizontal sinusoidal vibrations on the behaviour of a 3D sand granular medium. A transition from jammed or glassy states to a fluidized state has been observed for critical acceleration increasing with the frequency. Convective patterns have been encountered and characterised: two cylindrical counter-rotating rolls have been observed in the top of the packing. In addition, for high acceleration values, more complex patterns appear. The free surface at the top of the packing presents different shapes called “dome”, “dromedary” or “camel” depending on acceleration. One or three humps can be found. Analysis of grain movements and velocities along the walls of the container has been carried out and show that a stationary state can be reached after a transient regime. Finally the mechanisms of material transport through convective motion have been discussed

Analysis of the densification of a vibrated sand packing

“…The qualitative behaviour of the bed with respect to acceleration Γ as deduced in particular from our previous studies [13,22] is summarized in Fig. 1: above the onset of densification, three regions of the bed are observed: an upper one, showing convection rolls, a bottom region considered as jammed, showing almost no densification, and an intermediate "glassy" one, in which densification is expected to be enhanced.…”

“…The experimental device has been described in [13]. It consists in a mobile horizontal table, on which a container is fixed and partly filled in with the granular material (Fig.…”

“…A few 3D experimental works, in boxes with length L x (parallel to vibrations), L y , and pile height H large with respect to the particle diameter d have also been published [10][11][12]. Various phenomena are observed and studied such as convective flow [4,12,13], transition from a solid-like state to a fluid-like state [11,[13][14][15], size separation [16] and surface patterns [17][18][19]. Few studies investigated the bulk density evolution with the vibration parameters [20][21][22].…”

“…Fluidization is associated to an expansion of the granular medium in the fluidized region. In previous works [13,22], we also considered the onset of densification which occurs at an acceleration Γ 0 below Γ 1 . -the convective motions in the sample above this critical value, giving rise to one, two or more convective rolls on the top part of the powder bed.…”

Convection, Segregation and Pattern Formation in Horizontally Vibrated Granular Materials

“…[20,[70][71][72][73] . Convective motions detected inside granular systems are generally characterized into types of frictionally-driven convection [74,75] , buoyancydriven convection [76,77] , and substrate-mediated convection [78] .…”