Orifice jamming of fluid-driven granular flow

Lafond, Patrick G.; Gilmer, Matthew W.; Koh, Carolyn A.; Sloan, E. Dendy; Wu, David T.; Sum, Amadeu K.

doi:10.1103/physreve.87.042204

Cited by 57 publications

(58 citation statements)

References 27 publications

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“…And for small enough holes, stable arches can form and cause a clog [20]. Related behavior has been reported for the upward discharge of bubbles in an underwater silo [13], particles on a conveyor belt [14], and for disks floating on a fluid that flows through an orifice [15,16]. An important challenge is to relate all such phenomena to the velocity and density fields, which can be measured in quasi-2D [9,[21][22][23][24][25] and index-matched [26] systems.…”

Section: Introductionmentioning

confidence: 63%

Granular discharge rate for submerged hoppers

et al. 2014

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The discharge of spherical grains from a hole in the bottom of a right circular cylinder is measured with the entire system underwater. We find that the discharge rate depends on filling height, in contrast to the well-known case of dry non-cohesive grains. It is further surprising that the rate increases up to about twenty five percent, as the hopper empties and the granular pressure head decreases. For deep filling, where the discharge rate is constant, we measure the behavior as a function of both grain and hole diameters. The discharge rate scale is set by the product of hole area and the terminal falling speed of isolated grains. But there is a small-hole cutoff of about two and half grain diameters, which is larger than the analogous cutoff in the Beverloo equation for dry grains

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Section: Introductionmentioning

confidence: 63%

Granular discharge rate for submerged hoppers

et al. 2014

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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]. For noncohesive compact grains, in air or vacuum, there is general agreement that clogging statistics are Poissonian [6,7,13,26,27].…”

Section: Introductionmentioning

confidence: 87%

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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“…The exponential decay of the avalanche size distribution has been reported in several arrangements: 2D and 3D silos [16,20,21], 2D hoppers [22,23], 2D and 3D tilted hoppers and silos [24,25], silos with the presence of obstacles [26,27], 2D silos where the particles were driven by different gravity forces [28], and fluid driven particles in 2D and 3D [29,30]. However, there are some examples where this exponential tail breaks down.…”

Section: Avalanche Size Distributionmentioning

confidence: 95%

Invited review: Clogging of granular materials in bottlenecks

Zuriguel¹

2014

Pap. Phys.

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During the past decades, notable improvements have been achieved in the understanding of static and dynamic properties of granular materials, giving rise to appealing new concepts like jamming, force chains, non-local rheology or the inertial number. The 'saltcellar' can be seen as a canonical example of the characteristic features displayed by granular materials: an apparently smooth flow is interrupted by the formation of a mesoscopic structure (arch) above the outlet that causes a quick dissipation of all the kinetic energy within the system. In this manuscript, I will give an overview of this field paying special attention to the features of statistical distributions appearing in the clogging and unclogging processes. These distributions are essential to understand the problem and allow subsequent study of topics such as the influence of particle shape, the structure of the clogging arches and the possible existence of a critical outlet size above which the outpouring will never stop. I shall finally offer some hints about general ideas that can be explored in the next few years.

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Orifice jamming of fluid-driven granular flow

Cited by 57 publications

References 27 publications

Granular discharge rate for submerged hoppers

Granular discharge rate for submerged hoppers

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

Invited review: Clogging of granular materials in bottlenecks

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