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Caitano R, Garcimartín A, Zuriguel I. Anchoring Effect of an Obstacle in the Silo Unclogging Process. PHYSICAL REVIEW LETTERS 2023; 131:098201. [PMID: 37721817 DOI: 10.1103/physrevlett.131.098201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 07/20/2023] [Indexed: 09/20/2023]
Abstract
Contrary to the proven beneficial role that placing an obstacle above a silo exit has in clogging prevention, we demonstrate that, when the system is gently shaken, this passive element has a twofold effect in the clogging destruction process. On one side, the obstacle eases the destruction of weak arches, a phenomenon that can be explained by the pressure screening that it causes in the outlet proximities. But on the other side, we discover that the obstacle presence leads to the development of a few very strong arches. These arches, which dominate in the heavy tailed distributions of unclogging times, correlate with configurations where the number of particles contacting the obstacle from below are higher than the average; hence suggesting that the obstacle acts as an anchoring point for the granular packing. This finding may help one to understand the ambiguous effect of obstacles in the bottleneck flow of other systems, such as pedestrians evacuating a room or active matter in general.
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Affiliation(s)
- Rodrigo Caitano
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
| | - Angel Garcimartín
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
| | - Iker Zuriguel
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
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2
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Pongó T, Börzsönyi T, Cruz Hidalgo R. Discharge of elongated grains in silos under rotational shear. Phys Rev E 2022; 106:034904. [PMID: 36266860 DOI: 10.1103/physreve.106.034904] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/16/2022] [Indexed: 06/16/2023]
Abstract
The discharge of elongated particles from a silo with rotating bottom is investigated numerically. The introduction of a slight transverse shear reduces the flow rate Q by up to 70% compared with stationary bottom, but the flow rate shows a modest increase by further increasing the external shear. Focusing on the dependency of flow rate Q on orifice diameter D, the spheres and rods show two distinct trends. For rods, in the small-aperture limit Q seems to follow an exponential trend, deviating from the classical power-law dependence. These macroscopic observations are in good agreement with our earlier experimental findings [Phys. Rev. E 103, 062905 (2021)2470-004510.1103/PhysRevE.103.062905]. With the help of the coarse-graining methodology we obtain the spatial distribution of the macroscopic density, velocity, kinetic pressure, and orientation fields. This allows us detecting a transition from funnel to mass flow pattern caused by the external shear. Additionally, averaging these fields in the region of the orifice reveals that the strong initial decrease in Q is mostly attributed to changes in the flow velocity, while the weakly increasing trend at higher rotation rates is related to increasing packing fraction. Similar analysis of the grain orientation at the orifice suggests a correlation of the flow rate magnitude with the vertical orientation and the packing fraction at the orifice with the order of the grains. Lastly, the vertical profile of mean acceleration at the center of the silo denotes that the region where the acceleration is not negligible shrinks significantly due to the strong perturbation induced by the moving wall.
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Affiliation(s)
- Tivadar Pongó
- Física y Matemática Aplicada, Facultad de Ciencias, Universidad de Navarra, 31008 Pamplona, Spain
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary
| | - Tamás Börzsönyi
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary
| | - Raúl Cruz Hidalgo
- Física y Matemática Aplicada, Facultad de Ciencias, Universidad de Navarra, 31008 Pamplona, Spain
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3
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Zhang S, Ge W, Chen G, Liu Z, Liu T, Wen L, Liu C. Numerical investigation on the clogging-collapsing events in granular discharge. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Wu S, Lei Z, Jiang M, Liang J, Li B, Chen Y. Experimental investigation and discrete element modeling for particle-scale powder spreading dynamics in powder-bed-fusion-based additive manufacturing. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Caitano R, Guerrero BV, González RER, Zuriguel I, Garcimartín A. Characterization of the Clogging Transition in Vibrated Granular Media. PHYSICAL REVIEW LETTERS 2021; 127:148002. [PMID: 34652198 DOI: 10.1103/physrevlett.127.148002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
The existence of a transition from a clogged to an unclogged state has been recently proposed for the flow of macroscopic particles through bottlenecks in systems as diverse as colloidal suspensions, granular matter, or live beings. Here, we experimentally demonstrate that, for vibrated granular media, such a transition genuinely exists, and we characterize it as a function of the outlet size and vibration intensity. We confirm the suitability of the "flowing parameter" as the order parameter, and we find out that the rescaled maximum acceleration of the system should be replaced as the control parameter by a dimensionless velocity that can be seen as the square root of the ratio between kinetic and potential energy. In all the investigated scenarios, we observe that, for a critical value of this control parameter S_{c}, there seems to be a continuous transition to an unclogged state. The data can be rescaled with this critical value, which, as expected, decreases with the orifice size D. This leads to a phase diagram in the S-D plane in which clogging appears as a concave surface.
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Affiliation(s)
- R Caitano
- Depto. de Física y Mat. Apl., Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
| | - B V Guerrero
- Depto. de Física y Mat. Apl., Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
| | - R E R González
- Laboratório de Sistemas Complexos e Universais, Departamento de Física, Universidade Federal Rural de Pernambuco, Recife-PE, CEP 52171-900, Brasil
| | - I Zuriguel
- Depto. de Física y Mat. Apl., Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
| | - A Garcimartín
- Depto. de Física y Mat. Apl., Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain
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Garcimartín A, Guerrero BV, Nicolas A, Barbosa da Silva RC, Zuriguel I. On the broad tails in breaking time distributions of vibrated clogging arches. EPJ WEB OF CONFERENCES 2021. [DOI: 10.1051/epjconf/202124903009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Flowing grains can clog an orifice by developing arches, an undesirable event in many cases. Several strategies have been put forward to avoid this. One of them is to vibrate the system in order to undo the clogging. Nevertheless, the time taken to break an arch under a constant vibration has a distribution displaying a heavy tail. This can lead to a situation where the average breaking time is not well defined. Moreover, it has been observed in some experiments that these tails tend to flatten for very long times, exacerbating the problem. Here we will review two conceptual frameworks that have been proposed to understand the phenomenon and discuss their physical implications.
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Hernández-Delfin D, Pongó T, To K, Börzsönyi T, Hidalgo RC. Particle flow rate in silos under rotational shear. Phys Rev E 2020; 102:042902. [PMID: 33212719 DOI: 10.1103/physreve.102.042902] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
Very recently, To et al. have experimentally explored granular flow in a cylindrical silo, with a bottom wall that rotates horizontally with respect to the lateral wall [Phys. Rev. E 100, 012906 (2019)10.1103/PhysRevE.100.012906]. Here we numerically reproduce their experimental findings, in particular, the peculiar behavior of the mass flow rate Q as a function of the frequency of rotation f. Namely, we find that for small outlet diameters D the flow rate increased with f, while for larger D a nonmonotonic behavior is confirmed. Furthermore, using a coarse-graining technique, we compute the macroscopic density, momentum, and the stress tensor fields. These results show conclusively that changes in the discharge process are directly related to changes in the flow pattern from funnel flow to mass flow. Moreover, by decomposing the mass flux (linear momentum field) at the orifice into two main factors, macroscopic velocity and density fields, we obtain that the nonmonotonic behavior of the linear momentum is caused by density changes rather than by changes in the macroscopic velocity. In addition, by analyzing the spatial distribution of the kinetic stress, we find that for small orifices increasing rotational shear enhances the mean kinetic pressure 〈p^{k}〉 and the system dilatancy. This reduces the stability of the arches, and, consequently, the volumetric flow rate increases monotonically. For large orifices, however, we detected that 〈p^{k}〉 changes nonmonotonically, which might explain the nonmonotonic behavior of Q when varying the rotational shear.
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Affiliation(s)
- D Hernández-Delfin
- Departamento de Física y Matemática Aplicada, Universidad de Navarra, P.O. Box 31080, Navarra, Spain
| | - T Pongó
- Departamento de Física y Matemática Aplicada, Universidad de Navarra, P.O. Box 31080, Navarra, Spain
| | - K To
- Institute of Physics, Academia Sinica, P.O. Box 11529, Taipei, Taiwan R.O.C
| | - T Börzsönyi
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary
| | - R C Hidalgo
- Departamento de Física y Matemática Aplicada, Universidad de Navarra, P.O. Box 31080, Navarra, Spain
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Guerrero BV, Chakraborty B, Zuriguel I, Garcimartín A. Nonergodicity in silo unclogging: Broken and unbroken arches. Phys Rev E 2019; 100:032901. [PMID: 31639941 DOI: 10.1103/physreve.100.032901] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Indexed: 11/07/2022]
Abstract
We report an experiment on the unclogging dynamics in a two-dimensional silo submitted to a sustained gentle vibration. We find that arches present a jerking motion where rearrangements in the positions of their beads are interspersed with quiescent periods. This behavior occurs for both arches that break down and those that withstand the external perturbation: Arches evolve until they either collapse or get trapped in a stable configuration. This evolution is described in terms of a scalar variable characterizing the arch shape that can be modeled as a continuous-time random walk. By studying the diffusivity of this variable, we show that the unclogging is a weakly nonergodic process. Remarkably, arches that do not collapse explore different configurations before settling in one of them and break ergodicity much in the same way than arches that break down.
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Affiliation(s)
- B V Guerrero
- Dep. Física y Mat. Apl., Fac. Ciencias, Universidad de Navarra, 31080 Pamplona, Spain
| | - B Chakraborty
- Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02454, USA
| | - I Zuriguel
- Dep. Física y Mat. Apl., Fac. Ciencias, Universidad de Navarra, 31080 Pamplona, Spain
| | - A Garcimartín
- Dep. Física y Mat. Apl., Fac. Ciencias, Universidad de Navarra, 31080 Pamplona, Spain
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To K, Yen Y, Mo YK, Huang JR. Granular flow from silos with rotating orifice. Phys Rev E 2019; 100:012906. [PMID: 31499781 DOI: 10.1103/physreve.100.012906] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Indexed: 06/10/2023]
Abstract
For dry granular materials falling through a circular exit at the bottom of a silo, no continuous flow can be sustained when the diameter D of the exit is less than five times the characteristic size of the grains. If the bottom of the silo rotates horizontally with respect to the wall of the silo, finite flow rate can be sustained even at small D. We investigate the effect of bottom rotation to the flow rate of monodisperse plastic beads of d=6mm diameter from a cylindrical silo of 19 cm inner diameter. We find that the flow rate W follows Beverloo law down to D=1.3d and that W increases with the rotation speed ω in the small exit regime. If the exit is at an off-center distance R from the axis of the silo, W increases with the rate of area swept by the exit. On the other hand, when the exit diameter is large, W decreases with increasing ω at small ω but increases with ω at large ω. Such nonmonotonic dependence of flow rate on rotation speed may be explained as a gradual change from funnel flow to mass flow due to the shear at the bottom of the silo.
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Affiliation(s)
- Kiwing To
- Institute of Physics, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Yun Yen
- Institute of Physics, Academia Sinica, Taipei, Taiwan, Republic of China
- Department of Physics, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Yi-Kai Mo
- Institute of Physics, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Jung-Ren Huang
- Institute of Physics, Academia Sinica, Taipei, Taiwan, Republic of China
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Parisi DR, Cruz Hidalgo R, Zuriguel I. Active particles with desired orientation flowing through a bottleneck. Sci Rep 2018; 8:9133. [PMID: 29904139 PMCID: PMC6002477 DOI: 10.1038/s41598-018-27478-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/01/2018] [Indexed: 11/22/2022] Open
Abstract
We report extensive numerical simulations of the flow of anisotropic self-propelled particles through a constriction. In particular, we explore the role of the particles’ desired orientation with respect to the moving direction on the system flowability. We observe that when particles propel along the direction of their long axis (longitudinal orientation) the flow-rate notably reduces compared with the case of propulsion along the short axis (transversal orientation). And this is so even when the effective section (measured as the number of particles that are necessary to span the whole outlet) is larger for the case of longitudinal propulsion. This counterintuitive result is explained in terms of the formation of clogging structures at the outlet, which are revealed to have higher stability when the particles align along the long axis. This generic result might be applied to many different systems flowing through bottlenecks such as microbial populations or different kind of cells. Indeed, it has already a straightforward connection with recent results of pedestrian (which self-propel transversally oriented) and mice or sheep (which self-propel longitudinally oriented).
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Affiliation(s)
- Daniel R Parisi
- Instituto Tecnológico de Buenos Aires, CONICET, Lavardén 315, 1437 C, A. de Buenos Aires, Argentina.
| | - Raúl Cruz Hidalgo
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080, Pamplona, Spain
| | - Iker Zuriguel
- Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080, Pamplona, Spain
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11
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Nicolas A, Garcimartín Á, Zuriguel I. Trap Model for Clogging and Unclogging in Granular Hopper Flows. PHYSICAL REVIEW LETTERS 2018; 120:198002. [PMID: 29799232 DOI: 10.1103/physrevlett.120.198002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Indexed: 06/08/2023]
Abstract
Granular flows through narrow outlets may be interrupted by the formation of arches or vaults that clog the exit. These clogs may be destroyed by vibrations. A feature which remains elusive is the broad distribution p(τ) of clog lifetimes τ measured under constant vibrations. Here, we propose a simple model for arch breaking, in which the vibrations are formally equivalent to thermal fluctuations in a Langevin equation; the rupture of an arch corresponds to the escape from an energy trap. We infer the distribution of trap depths from experiments made in two-dimensional hoppers. Using this distribution, we show that the model captures the empirically observed heavy tails in p(τ). These heavy tails flatten at large τ, consistently with experimental observations under weak vibrations. But, here, we find that this flattening is systematic, which casts doubt on the ability of gentle vibrations to restore a finite outflow forever. The trap model also replicates recent results on the effect of increasing gravity on the statistics of clog formation in a static silo. Therefore, the proposed framework points to a common physical underpinning to the processes of clogging and unclogging, despite their different statistics.
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Affiliation(s)
- Alexandre Nicolas
- LPTMS, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Ángel Garcimartín
- Departamento de Física y Matemática Aplicada, Facultad de Ciencias, Universidad de Navarra, 31080 Pamplona, Spain
| | - Iker Zuriguel
- Departamento de Física y Matemática Aplicada, Facultad de Ciencias, Universidad de Navarra, 31080 Pamplona, Spain
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