Invited review: Clogging of granular materials in bottlenecks

Zuriguel, Iker

doi:10.4279/pip.060014

Cited by 70 publications

(67 citation statements)

References 64 publications

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“…The angle θ of the incline allows us to vary the component of the gravity parallel to the hopper plane, granting control of the force that drives the discharge. These systems are known to be prone to clogging [26][27][28] and vibration is a mechanism to resume the flow [29][30][31]. The granular material is composed of 500 spherical glass beads, and the outlet size is three times wider than the particle diameter.…”

Section: Resultsmentioning

confidence: 99%

Experimental proof of faster-is-slower in systems of frictional particles flowing through constrictions

et al. 2015

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The "faster-is-slower" (FIS) effect was first predicted by computer simulations of the egress of pedestrians through a narrow exit [D. Helbing, I. J. Farkas, and T. Vicsek, Nature (London) 407, 487 (2000)]. FIS refers to the finding that, under certain conditions, an excess of the individuals' vigor in the attempt to exit causes a decrease in the flow rate. In general, this effect is identified by the appearance of a minimum when plotting the total evacuation time of a crowd as a function of the pedestrian desired velocity. Here, we experimentally show that the FIS effect indeed occurs in three different systems of discrete particles flowing through a constriction: (a) humans evacuating a room, (b) a herd of sheep entering a barn, and (c) grains flowing out a 2D hopper over a vibrated incline. This finding suggests that FIS is a universal phenomenon for active matter passing through a narrowing.

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Section: Resultsmentioning

confidence: 99%

Experimental proof of faster-is-slower in systems of frictional particles flowing through constrictions

et al. 2015

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“…[10,11], which happens less frequently for larger holes and is unavoidable for holes smaller than about four to five grains across. Details depend on grain shape (see, e.g., [12][13][14][15]), and similar phenomena arise in other contexts, ranging from transport in electronic [16] and particulate [17,18] systems with spatially distributed pinning sites to grains in channels and pipes [19,20], grains driven by fluid flow [21,22], and even grains with brains: pedestrians [23], traffic [24], and livestock [25].…”

Section: Introductionmentioning

confidence: 99%

Effect of interstitial fluid on the fraction of flow microstates that precede clogging in granular hoppers

Koivisto

Durian

2017

Phys. Rev. E

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We report on the nature of flow events for the gravity-driven discharge of glass beads through a hole that is small enough that the hopper is susceptible to clogging. In particular, we measure the average and standard deviation of the distribution of discharged masses as a function of both hole and grain sizes. We do so in air, which is usual, but also with the system entirely submerged under water. This damps the grain dynamics and could be expected to dramatically affect the distribution of the flow events, which are described in prior work as avalanche-like. Though the flow is slower and the events last longer, we find that the average discharge mass is only slightly reduced for submerged grains. Furthermore, we find that the shape of the distribution remains exponential, implying that clogging is still a Poisson process even for immersed grains. Per Thomas and Durian [Phys. Rev. Lett. 114, 178001 (2015)], this allows for an interpretation of the average discharge mass in terms of the fraction of flow microstates that precede, i.e., that effectively cause, a stable clog to form. Since this fraction is barely altered by water, we conclude that the crucial microscopic variables are the grain positions; grain momenta play only a secondary role in destabilizing weak incipient arches. These insights should aid ongoing efforts to understand the susceptibility of granular hoppers to clogging. We report on the nature of flow events for the gravity-driven discharge of glass beads through a hole that is small enough that the hopper is susceptible to clogging. In particular, we measure the average and standard deviation of the distribution of discharged masses as a function of both hole and grain sizes. We do so in air, which is usual, but also with the system entirely submerged under water. This damps the grain dynamics and could be expected to dramatically affect the distribution of the flow events, which are described in prior work as avalanche-like. Though the flow is slower and the events last longer, we find that the average discharge mass is only slightly reduced for submerged grains. Furthermore, we find that the shape of the distribution remains exponential, implying that clogging is still a Poisson process even for immersed grains. Per Thomas and Durian [Phys. Rev. Lett. 114, 178001 (2015)], this allows for an interpretation of the average discharge mass in terms of the fraction of flow microstates that precede, i.e., that effectively cause, a stable clog to form. Since this fraction is barely altered by water, we conclude that the crucial microscopic variables are the grain positions; grain momenta play only a secondary role in destabilizing weak incipient arches. These insights should aid ongoing efforts to understand the susceptibility of granular hoppers to clogging.

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“…This Beberloo's law is a useful relation to estimate the granular flow rate when the size of orifice is large enough. However, when the orifice size is smaller than six times of particle diameter, clogging of the flow can readily be observed [2,3]. In such unstable flow regime, size distribution of avalanches has been measured and analyzed extensively [4].…”

Section: Introductionmentioning

confidence: 99%

Statistical properties of gravity-driven granular discharge flow under the influence of an obstacle

Endo

Katsuragi

2017

EPJ Web Conf.

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Abstract. Two-dimensional granular discharge flow driven by gravity under the influence of an obstacle is experimentally investigated. A horizontal exit of width W is opened at the bottom of vertical Hele-Shaw cell filled with stainless-steel particles to start the discharge flow. In this experiment, a circular obstacle is placed in front of the exit. Thus, the distance between the exit and obstacle L is also an important parameter. During the discharge, granular-flow state is acquired by a high-speed camera. The bulk discharge-flow rate is also measured by load cell sensors. The obtained high-speed-image data are analyzed to clarify the particle-level granular-flow dynamics. Using the measured data, we find that the obstacle above the exit affects the granularflow field. Specifically, the existence of obstacle results in large horizontal granular temperature and small packing fraction. This tendency becomes significant when L is smaller than approximately 6D g when W 4D g , where D g is diameter of particles.

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Invited review: Clogging of granular materials in bottlenecks

Cited by 70 publications

References 64 publications

Experimental proof of faster-is-slower in systems of frictional particles flowing through constrictions

Experimental proof of faster-is-slower in systems of frictional particles flowing through constrictions

Effect of interstitial fluid on the fraction of flow microstates that precede clogging in granular hoppers

Statistical properties of gravity-driven granular discharge flow under the influence of an obstacle

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