Dynamics of breaking arches under a constant vibration

Abstract

Abstract. Granular flow through an orifice can be suddenly halted by the formation of arches in the vicinity of the outlet, which are stable under the action of gravity. They may be broken when an external driving (for instance, vibration) is applied. With the aim of shedding light on the dynamics of arch destruction, we built an experiment consisting of a vertical two-dimensional silo filled with monodisperse beads, to which a constant vibration is applied. It was previously found that an important parameter to predict the robustness of the arch is the angle between consecutive beads. We focus on long-enduring arches and study the angles among the beads along time. We have found that in many cases the dynamics of the largest angle determines the breaking of the arch; it does not only determine where the "weakest link" is, but also the process that leads to the final destabilization. This is interesting because it can provide information about whether the flow will resume in a well-defined time or not, which is especially useful for industrial processes that have to constantly deal with the possible emergence of clogs.

Influence of mechanical vibrations on quasi-2D silo discharge of spherical particles

“…In particular,Govender et al [16] have shown that arches and clogging are often caused by particle shape, which cannot be captured by rolling friction with spheres, and hence cannot be accurately captured by the Beverloo law. The clogging of silos due to arches formation is often avoided in practical situations, such as industrial silos, by imparting vibrations to the container [17,18,19,20]. Previous studies have shown that vibrations allow the flow in normally jammed cases, either due to small opening sizes [18], the silo configuration [21] or the shape of the particles [22].…”

Comment on Maraveas, C. Concrete Silos: Failures, Design Issues and Repair/Strengthening Methods. Appl. Sci. 2020, 10, 3938

“…If gravity alone is insufficient to enable flow, then other forces such as external accelerations can be introduced to enable the particles to flow [32][33][34][35][36]. This phenomenon can be readily observed in a saltshaker, where the salt particles do not flow out of the saltshaker readily without the user shaking it because outlets are small; thus, the resistant forces are significantly higher than the gravity force that causes the particles to flow.…”

Nonergodicity in silo unclogging: Broken and unbroken arches

“…Furthering that line of research, Guerrero and coworkers [29,30] used the same experimental device and studied how arches evolve along time when they are perturbed with a gentle constant vibration. They tracked the position of the arch beads during the arch lifespan.…”