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Voigtländer A, Houssais M, Bacik KA, Bourg IC, Burton JC, Daniels KE, Datta SS, Del Gado E, Deshpande NS, Devauchelle O, Ferdowsi B, Glade R, Goehring L, Hewitt IJ, Jerolmack D, Juanes R, Kudrolli A, Lai CY, Li W, Masteller C, Nissanka K, Rubin AM, Stone HA, Suckale J, Vriend NM, Wettlaufer JS, Yang JQ. Soft matter physics of the ground beneath our feet. SOFT MATTER 2024. [PMID: 39012310 DOI: 10.1039/d4sm00391h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
The soft part of the Earth's surface - the ground beneath our feet - constitutes the basis for life and natural resources, yet a general physical understanding of the ground is still lacking. In this critical time of climate change, cross-pollination of scientific approaches is urgently needed to better understand the behavior of our planet's surface. The major topics in current research in this area cross different disciplines, spanning geosciences, and various aspects of engineering, material sciences, physics, chemistry, and biology. Among these, soft matter physics has emerged as a fundamental nexus connecting and underpinning many research questions. This perspective article is a multi-voice effort to bring together different views and approaches, questions and insights, from researchers that work in this emerging area, the soft matter physics of the ground beneath our feet. In particular, we identify four major challenges concerned with the dynamics in and of the ground: (I) modeling from the grain scale, (II) near-criticality, (III) bridging scales, and (IV) life. For each challenge, we present a selection of topics by individual authors, providing specific context, recent advances, and open questions. Through this, we seek to provide an overview of the opportunities for the broad Soft Matter community to contribute to the fundamental understanding of the physics of the ground, strive towards a common language, and encourage new collaborations across the broad spectrum of scientists interested in the matter of the Earth's surface.
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Affiliation(s)
- Anne Voigtländer
- German Research Centre for Geosciences (GFZ), Geomorphology, Telegrafenberg, 14473 Potsdam, Germany.
- Lawrence Berkeley National Laboratory (LBNL), Energy Geosciences Division, 1 Cyclotron Rd, Berkeley, CA 94720, USA
| | - Morgane Houssais
- Department of Physics, Clark University, 950 Main St, Worcester, MA 01610, USA
| | - Karol A Bacik
- Department of Mathematics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Ian C Bourg
- Civil and Environmental Engineering (CEE) and High Meadows Environmental Institute (HMEI), Princeton University, E208 EQuad, Princeton, NJ 08540, USA
| | - Justin C Burton
- Department of Physics, Emory University, 400 Dowman Dr, Atlanta, GA 30033, USA
| | - Karen E Daniels
- North Carolina State University, 2401 Stinson Dr, Raleigh, NC 27607, USA
| | - Sujit S Datta
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Emanuela Del Gado
- Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC, USA
| | - Nakul S Deshpande
- North Carolina State University, 2401 Stinson Dr, Raleigh, NC 27607, USA
| | - Olivier Devauchelle
- Institut de Physique du Globe de Paris, Université Paris Cité, 1 rue Jussieu, CNRS, F-75005 Paris, France
| | - Behrooz Ferdowsi
- Department of Civil and Environmental Engineering, jUniversity of Houston, Houston, TX 77204, USA
| | - Rachel Glade
- Earth & Environmental Sciences Department and Mechanical Engineering Department, University of Rochester, 227 Hutchison Hall, P.O. Box 270221, Rochester, NY 14627, USA
| | - Lucas Goehring
- School of Science and Technology, Nottingham Trent University, Nottingham NG11 8NS, UK
| | - Ian J Hewitt
- Mathematical Institute, University of Oxford, Woodstock Road, Oxford OX2 6GG, UK
| | - Douglas Jerolmack
- Department of Earth & Environmental Science, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ruben Juanes
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Arshad Kudrolli
- Department of Physics, Clark University, 950 Main St, Worcester, MA 01610, USA
| | - Ching-Yao Lai
- Department of Geophysics, Stanford University, Stanford, CA 94305, USA
| | - Wei Li
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Stony Brook University, Department of Civil Engineering, Stony Brook, NY 11794, USA
| | - Claire Masteller
- Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, USA
| | - Kavinda Nissanka
- Department of Physics, Emory University, 400 Dowman Dr, Atlanta, GA 30033, USA
| | - Allan M Rubin
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Jenny Suckale
- Computational and Mathematical Engineering, and Environmental Engineering, Stanford University, Stanford, CA 94305, USA
| | - Nathalie M Vriend
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - John S Wettlaufer
- Departments of Earth & Planetary Sciences, Mathematics and Physics, Yale University, New Haven, CT 06520, USA
- Nordic Institute for Theoretical Physics, 106 91, Stockholm, Sweden
| | - Judy Q Yang
- Saint Anthony Falls Laboratory and Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, MN, USA
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2
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Singh AP, Angelidakis V, Pöschel T, Roy S. Shear zones in granular mixtures of hard and soft particles with high and low friction. SOFT MATTER 2024; 20:3118-3130. [PMID: 38451109 DOI: 10.1039/d4sm00100a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Granular materials show inhomogeneous flows characterized by strain localization. When strain is localized in a sheared granular material, rigid regions of a nearly undeformed state are separated by shear bands, where the material yields and flows. The characteristics of the shear bands are determined by the geometry of the system, the micromechanical material properties, and the kinematics at the particle level. For a split-bottom shear cell, recent experimental work has shown that mixtures of hard, frictional and soft, nearly frictionless particles exhibit wider shear zones than samples with only one of the two components. To explain this finding, we investigate the shear zone properties and the stress response of granular mixtures using discrete element simulations. We show that both interparticle friction and elastic modulus determine the shear-band properties and packing density of granular mixtures of various mixing ratios, but their stress response depends strongly on the interparticle friction. Our study provides a fundamental understanding of the micromechanics of shear band formation in granular mixtures.
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Affiliation(s)
- Aditya Pratap Singh
- Institute for Multiscale Simulation, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstrasse 3, 91058 Erlangen, Germany.
| | - Vasileios Angelidakis
- Institute for Multiscale Simulation, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstrasse 3, 91058 Erlangen, Germany.
- School of Natural and Built Environment, Queen's University Belfast, David Keir Building, BT9 5AG Belfast, UK
| | - Thorsten Pöschel
- Institute for Multiscale Simulation, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstrasse 3, 91058 Erlangen, Germany.
| | - Sudeshna Roy
- Institute for Multiscale Simulation, Friedrich-Alexander-Universität Erlangen-Nürnberg, Cauerstrasse 3, 91058 Erlangen, Germany.
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3
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Li W, Juanes R. Dynamic imaging of force chains in 3D granular media. Proc Natl Acad Sci U S A 2024; 121:e2319160121. [PMID: 38527198 PMCID: PMC10998587 DOI: 10.1073/pnas.2319160121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 02/25/2024] [Indexed: 03/27/2024] Open
Abstract
Granular media constitute the most abundant form of solid matter on Earth and beyond. When external forces are applied to a granular medium, the forces are transmitted through it via chains of contacts among grains-force chains. Understanding the spatial structure and temporal evolution of force chains constitutes a fundamental goal of granular mechanics. Here, we introduce an experimental technique, interference optical projection tomography, to study force chains in three-dimensional (3D) granular packs under triaxial shear loads and illustrate the technique with random assemblies of spheres and icosahedra. We find that, in response to an increasing vertical load, the pack of spheres forms intensifying vertical force chains, while the pack of icosahedra forms more interconnected force-chain networks. This provides microscopic insights into why particles with more angularity are more resistant to shear failure-the interconnected force-chain network is stronger (that is, more resilient to topological collapse) than the isolated force chains in round particles. The longer force chains with less branching in the pack of round particles are more likely to buckle, which leads to the macroscopic failure of the pack. This work paves the way for understanding the grain-scale underpinning of localized failure of 3D granular media, such as shear localization in landslides and stick-slip frictional motion in tectonic and induced earthquakes.
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Affiliation(s)
- Wei Li
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA02139
- Department of Civil Engineering, Stony Brook University, Stony Brook, NY11794
| | - Ruben Juanes
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA02139
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4
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Wu Y, Sun Y, Wang D. The combined effect of cohesion and finite size on the collapse of wet granular columns. SOFT MATTER 2023. [PMID: 38050468 DOI: 10.1039/d3sm01259j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
The collapse of low-saturation liquid-containing granular materials is prevalent in nature and industrial processes, and understanding the associated transient dynamics is extremely important for exploring such complex flow processes. In this paper, the collapse of a finite-size wet granular column is systematically studied and the determinants affecting its dynamics are analyzed based on the discrete element model for wet particles and the corresponding small-scale experiments. With the aid of parametric analysis, the dimensionless cohesion parameter containing the system size and grain-scale bond number is proposed, and its relevance in characterizing column stability and collapse dynamics of wet granular materials is further confirmed. For the collapse of wet granular columns with a fixed aspect ratio, the initial height contained in the cohesion parameter is verified to be a manifestation of the finite size effect, which is present in a wet granular collapse and is coupled with the cohesive effect. Such a coupling effect is taken into account in our proposed scaling laws that can be applied to uniformly describe the deposit morphology of wet granular columns after collapse.
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Affiliation(s)
- Yisong Wu
- Department of Mechanics and Engineering Science, School of Civil Engineering and Mechanics, and Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education of China, Lanzhou University, Lanzhou 730000, China.
| | - Yinghao Sun
- Department of Mechanics and Engineering Science, School of Civil Engineering and Mechanics, and Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education of China, Lanzhou University, Lanzhou 730000, China.
| | - Dengming Wang
- Department of Mechanics and Engineering Science, School of Civil Engineering and Mechanics, and Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education of China, Lanzhou University, Lanzhou 730000, China.
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5
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Poon RN, Thomas AL, Vriend NM. Microscopic origin of granular fluidity: An experimental investigation. Phys Rev E 2023; 108:064902. [PMID: 38243449 DOI: 10.1103/physreve.108.064902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 10/30/2023] [Indexed: 01/21/2024]
Abstract
Granular fluidity has been central to the development of nonlocal constitutive equations, which are necessary for characterizing nonlocal effects observed in experimental granular flow data. However, validation of these equations has been largely computational due to challenges in laboratory experiments. Specifically, the origin of the fluidity on a microscopic, single-particle level is still unproven. In this work, we present an experimental validation of a microscopic definition of granular fluidity, and show the importance of basal boundary conditions to the validity of the theory.
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Affiliation(s)
- Rebecca N Poon
- BP Institute, University of Cambridge, Madingley Rise, Madingley Road, Cambridge CB3 0EZ, United Kingdom
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom†
| | - Amalia L Thomas
- BP Institute, University of Cambridge, Madingley Rise, Madingley Road, Cambridge CB3 0EZ, United Kingdom
- Department of Applied Mathematics & Theoretical Physics, University of Cambridge, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA, United Kingdom
| | - Nathalie M Vriend
- BP Institute, University of Cambridge, Madingley Rise, Madingley Road, Cambridge CB3 0EZ, United Kingdom
- Department of Applied Mathematics & Theoretical Physics, University of Cambridge, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA, United Kingdom
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
- Paul M. Rady Department of Mechanical Engineering, University of Colorado, Boulder, 1111 Engineering Drive, Boulder, Colorado 80309, USA†
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6
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Wang J, Fan B, Pongó T, Börzsönyi T, Cruz Hidalgo R, Stannarius R. Force on a sphere suspended in flowing granulate. Phys Rev E 2023; 108:L062901. [PMID: 38243450 DOI: 10.1103/physreve.108.l062901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 11/05/2023] [Indexed: 01/21/2024]
Abstract
We investigate the force of flowing granular material on an obstacle. A sphere suspended in a discharging silo experiences both the weight of the overlaying layers and drag of the surrounding moving grains. In experiments with frictional hard glass beads, the force on the obstacle was practically flow-rate independent. In contrast, flow of nearly frictionless soft hydrogel spheres added drag to the gravitational force. The dependence of the total force on the obstacle diameter is qualitatively different for the two types of material: It grows quadratically with the obstacle diameter in the soft, low-friction material, while it grows much weaker, nearly linearly with the obstacle diameter, in the bed of glass spheres. In addition to the drag, the obstacle embedded in flowing low-friction soft particles experiences a total force from the top as if immersed in a hydrostatic pressure profile, but a much lower counterforce acting from below. In contrast, when embedded in frictional, hard particles, a strong pressure gradient forms near the upper obstacle surface.
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Affiliation(s)
- Jing Wang
- Institute of Physics, Otto von Guericke University, Magdeburg, Germany
| | - Bo Fan
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Budapest, Hungary
- Physical Chemistry and Soft Matter, Wageningen University & Research, Wageningen, The Netherlands
| | - Tivadar Pongó
- Física y Matemática Aplicada, Facultad de Ciencias, Universidad de Navarra, Pamplona, Spain
- Collective Dynamics Lab, Division of Natural and Applied Sciences, Duke Kunshan University, Kunshan, China
| | - Tamás Börzsönyi
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Budapest, Hungary
| | - Raúl Cruz Hidalgo
- Física y Matemática Aplicada, Facultad de Ciencias, Universidad de Navarra, Pamplona, Spain
| | - Ralf Stannarius
- Institute of Physics, Otto von Guericke University, Magdeburg, Germany
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7
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Hao J, Guo Y, Yu Z, Curtis JS. Pressure‐controlled secondary flows and mixing in sheared Platonic solid‐shaped particles. AIChE J 2023. [DOI: 10.1002/aic.18090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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8
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Fazelpour F, Daniels KE. Controlling rheology via boundary conditions in dense granular flows. SOFT MATTER 2023; 19:2168-2175. [PMID: 36852754 DOI: 10.1039/d2sm00683a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Boundary shape, particularly roughness, strongly controls the amount of wall slip in dense granular flows. In this paper, we aim to quantify and understand which aspects of a dense granular flow are controlled by the boundary conditions, and to incorporate these observations into a cooperative nonlocal model characterizing slow granular flows. To examine the influence of boundary properties, we perform experiments on a quasi-2D annular shear cell with a rotating inner wall and a fixed outer wall; the latter is selected among 6 walls with various roughnesses, local concavity, and compliance. We find that we can successfully capture the full flow profile using a single set of empirically determined model parameters, with only the wall slip velocity set by direct observation. Through the use of photoelastic particles, we observe how the internal stresses fluctuate more for rougher boundaries, corresponding to a lower wall slip, and connect this observation to the propagation of nonlocal effects originating from the wall. Our measurements indicate a universal relationship between dimensionless fluidity and velocity.
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Affiliation(s)
- Farnaz Fazelpour
- Department of Physics, North Carolina State University, Raleigh, NC, USA.
| | - Karen E Daniels
- Department of Physics, North Carolina State University, Raleigh, NC, USA.
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9
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Clark AH, Brodsky EE, Nasrin HJ, Taylor SE. Frictional Weakening of Vibrated Granular Flows. PHYSICAL REVIEW LETTERS 2023; 130:118201. [PMID: 37001108 DOI: 10.1103/physrevlett.130.118201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 12/08/2022] [Accepted: 02/08/2023] [Indexed: 06/19/2023]
Abstract
We computationally study the frictional properties of sheared granular media subjected to harmonic vibration applied at the boundary. Such vibrations are thought to play an important role in weakening flows, yet the independent effects of amplitude, frequency, and pressure on the process have remained unclear. Based on a dimensional analysis and DEM simulations, we show that, in addition to a previously proposed criterion for peak acceleration that leads to breaking of contacts, weakening requires the absolute amplitude squared of the displacement to be sufficiently large relative to the confining pressure. The analysis provides a basis for predicting flows subjected to arbitrary external vibration and demonstrates that a previously unrecognized second process that is dependent on dissipation contributes to shear weakening under vibrations.
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Affiliation(s)
- Abram H Clark
- Department of Physics, Naval Postgraduate School, Monterey, California 93943, USA
| | - Emily E Brodsky
- Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - H John Nasrin
- Naval Surface Warfare Center, Carderock Division, Bethesda, Maryland 20817, USA
| | - Stephanie E Taylor
- Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, California 95064, USA
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10
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Farain K, Bonn D. Quantitative Understanding of the Onset of Dense Granular Flows. PHYSICAL REVIEW LETTERS 2023; 130:108201. [PMID: 36962056 DOI: 10.1103/physrevlett.130.108201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 06/23/2022] [Accepted: 02/21/2023] [Indexed: 06/18/2023]
Abstract
The question of when and how dense granular materials start to flow under stress, despite many industrial and geophysical applications, remains largely unresolved. We develop and test a simple equation for the onset of quasistatic flows of granular materials which is based on the frictional aging of the granular packing. The result is a nonmonotonic stress-strain relation which-akin to classical friction-is independent of the shear rate. This relation suffices to understand the quasistatic deformations of aging granular media, and its solid-to-liquid transition. Our results also elucidate the (flow) history dependence of the mechanical properties, and the sensitivity to the initial preparation of granular media.
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Affiliation(s)
- Kasra Farain
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098XH Amsterdam, Netherlands
| | - Daniel Bonn
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098XH Amsterdam, Netherlands
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11
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Hong G, Zhou Y, Li J. Relaxation dynamics of vibrated dense granular media: Hysteresis and nonlocal effects. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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12
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Tsigginos C, Meng J, Gu XJ, Emerson DR. Coupled LBM-DEM simulations using the partially saturated method: Theoretical and computational aspects. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Guo Q, Zhang Y, Vazquez C, Xi K, Boyce CM. Multi‐Fluid
Model Simulations of Gravitational Instabilities in Fluidized Binary Granular Materials. AIChE J 2022. [DOI: 10.1002/aic.17714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Qiang Guo
- Department of Chemical Engineering Columbia University New York New York USA
| | - Yuxuan Zhang
- Department of Chemical Engineering Columbia University New York New York USA
| | - Carolina Vazquez
- Department of Chemical Engineering Columbia University New York New York USA
| | - Kenan Xi
- Department of Chemical Engineering Columbia University New York New York USA
- State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University China
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14
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Fazelpour F, Tang Z, Daniels KE. The effect of grain shape and material on the nonlocal rheology of dense granular flows. SOFT MATTER 2022; 18:1435-1442. [PMID: 35080563 DOI: 10.1039/d1sm01237a] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nonlocal rheologies allow for the modeling of granular flows from the creeping to intermediate flow regimes, using a small number of parameters. In this paper, we report on experiments testing how particle properties affect the model parameters used in the Kamrin & Koval cooperative nonlocal model, using particles of three different shapes (circles, ellipses, and pentagons) and three different materials, including one which allows for the measurement of stresses via photoelasticity. Our experiments are performed on a quasi-2D annular shear cell with a rotating inner wall and a fixed outer wall. Each type of particle is found to exhibit flows which are well-fit by nonlocal rheology, with each particle having a distinct triad of the local, nonlocal, and frictional parameters. While the local parameter b is always approximately unity, the nonlocal parameter A depends sensitively on both the particle shape and material. The critical stress ratio μs, above which Coulomb failure occurs, varies for particles with the same material but different shape, indicating that geometric friction can dominate over material friction.
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Affiliation(s)
- Farnaz Fazelpour
- Department of Physics, North Carolina State University, Raleigh, NC, USA.
| | - Zhu Tang
- Department of Physics, North Carolina State University, Raleigh, NC, USA.
| | - Karen E Daniels
- Department of Physics, North Carolina State University, Raleigh, NC, USA.
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15
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Sun A, Wang Y, Chen Y, Shang J, Zheng J, Yu S, Su S, Sun X, Zhang J. Turbulent-like velocity fluctuations in two-dimensional granular materials subject to cyclic shear. SOFT MATTER 2022; 18:983-989. [PMID: 35014635 DOI: 10.1039/d1sm01516h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We perform a systematic experimental study to investigate the velocity fluctuations in the two-dimensional granular matter of low and high friction coefficients subjected to cyclic shear of a range of shear amplitudes, whose velocity fields are strikingly turbulent-like with vortices of different scales. The scaling behaviors of both the transverse velocity power spectra ET(k) ∝ k-αT and, more severely, the longitudinal velocity power spectra EL(k) ∝ k-αL are affected by the prominent peak centered around k ≈ 2π of the inter-particle distance due to the static structure factor of the hard-particle nature in contrast to the real turbulence. To reduce the strong peak effect to the actual values of αν (the subscript 'ν' refers to either T or L), we subsequently analyze the second-order velocity structure functions of S(2)ν(r) in real space, which show the power-law scalings of S(2)ν(r) ∝ rβν for both modes. From the values of βν, we deduce the corresponding αν from the scaling relations of αν = βν + 2. The deduced values of αν increase continuously with the shear amplitude γm, showing no signature of yielding transition, and are slightly larger than αν = 2.0 at the limit of γm → 0, which corresponds to the elastic limit of the system, for all γm. The inter-particle friction coefficients show no significant effect on the turbulent-like velocity fluctuations. Our findings suggest that the turbulent-like collective particle motions are governed by both the elasticity and plasticity in cyclically sheared granular materials.
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Affiliation(s)
- Aile Sun
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Yinqiao Wang
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Yangrui Chen
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Jin Shang
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Jie Zheng
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Shuchang Yu
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Siyuan Su
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Xulai Sun
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Jie Zhang
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
- Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
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16
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Benyahia S. Selecting the best approach for fluidized bed simulation of aeratable particles. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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17
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The Development and Application of a TFM for Dense Particle Flow and Mixing in Rotating Drums. Processes (Basel) 2022. [DOI: 10.3390/pr10020234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The two-fluid model (TFM) coupled with the kinetic theory of granular flow (KTGF) has gradually been used for modeling dense granular flows and mixing in rotating drums in recent years. In the present paper, a review is made from the perspective of model development and model application. It is found that several frictional viscosity models were proposed to consider the enduring contact of dense particles for the specific rotating studied, but there is still a lack of a universal model. The model is validated by various experiment results and the applicability is indicated. The model is used for investigating dynamic particle flow, and the effects of the parameters on granular flow behavior and flight design. Although the model theoretically has the advantage of saving computing resources, and is suitable for industrial-scale modeling, it is found that the model is used for the research of laboratory-scale rotating drums (diameter less than 0.5 m) and has not been used for industrial rotating drum analysis. Moreover, recommendations for future work are provided.
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18
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Zhang D, Dong S, Guo H, Yang X, Cui L, Liu X. Flow behavior of granular material during funnel and mixed flow discharges: A comparative analysis. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2021.10.047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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19
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Shaebani MR, Török J, Maleki M, Madani M, Harrington M, Rice A, Losert W. Gravity Governs Shear Localization in Confined Dense Granular Flows. PHYSICAL REVIEW LETTERS 2021; 127:278003. [PMID: 35061419 DOI: 10.1103/physrevlett.127.278003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 10/10/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
The prediction of flow profiles of slowly sheared granular materials is a major geophysical and industrial challenge. Understanding the role of gravity is particularly important for future planetary exploration in varying gravitational environments. Using the principle of minimization of energy dissipation, and combining experiments and variational analysis, we disentangle the contributions of the gravitational acceleration, confining pressure, and layer thickness on shear strain localization induced by moving fault boundaries at the bottom of a granular layer. The flow profile is independent of the gravity for geometries with a free top surface. However, under a confining pressure or if the sheared layer withstands the weight of the upper layers, increasing gravity promotes the transition from closed shear zones buried in the bulk to open ones that intersect the top surface. We show that the center position and width of the shear zone and the axial angular velocity at the top surface follow universal scaling laws when properly scaled by the gravity, applied pressure, and layer thickness. Our finding that the flow profiles lie on a universal master curve opens the possibility to predict the quasistatic shear flow of granular materials in varying gravitational environments.
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Affiliation(s)
- M Reza Shaebani
- Department of Theoretical Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany
| | - János Török
- MTA-BME Morphodynamics Research Group, Department of Theoretical Physics, Budapest University of Technology and Economics, Budapest H-1111, Hungary
| | - Maniya Maleki
- Department of Physics & Optics Research Center, Institute for Advanced Studies in Basic Sciences, Zanjan 45137-66731, Iran
| | - Mahnoush Madani
- Department of Physics & Optics Research Center, Institute for Advanced Studies in Basic Sciences, Zanjan 45137-66731, Iran
| | - Matt Harrington
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Allyson Rice
- Department of Biophysics Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Wolfgang Losert
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
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20
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Lee J. Regime changes of industrial powder mixing in a stirred vessel. POWDER TECHNOL 2021. [DOI: 10.1016/j.powtec.2021.07.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Wang D, Nejadsadeghi N, Li Y, Shekhar S, Misra A, Dijksman JA. Rotational diffusion and rotational correlations in frictional amorphous disk packings under shear. SOFT MATTER 2021; 17:7844-7852. [PMID: 34323255 DOI: 10.1039/d1sm00525a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We show here that rotations of round particles in amorphous disk packing reveal various nontrivial microscopic features when the packing is close to rigidification. We analyze experimental measurements on disk packing subjected to simple shear deformation with various inter-particle friction coefficients and across a range of volume fractions where the system is known to stiffen. The analysis of measurements indicates that shear induces diffusive microrotation, that can be both enhanced and suppressed depending upon the volume fraction as well as the inter-particle friction. Rotations also display persistent anticorrelated motion. Spatial correlations in microrotation are observed to be directly correlated with system pressure. These observations point towards the broader mechanical relevance of collective dynamics in the rotational degree of freedom of particles.
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Affiliation(s)
- Dong Wang
- Department of Physics & Center for Non-linear and Complex Systems, Duke University, Durham, North Carolina 27708, USA
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22
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Hossain M, Zhu HP, Yu AB. Numerical investigation on effect of particle aspect ratio on the dynamical behaviour of ellipsoidal particle flow. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:455102. [PMID: 34371486 DOI: 10.1088/1361-648x/ac1bd0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
Flow of ellipsoidal particles in a modal shear cell was investigated at the microdynamic level based on discrete element method simulations. In a stress-controlled double-shear condition, the flow was studied by varying the aspect ratio of ellipsoidal particles and comparing with the flow of spherical particle assembly in terms of some key properties, including particle alignment, linear velocity, angular velocity, porosity, contact force and contact energy. It was found that particle elongation impacts the rotational displacement around the axis perpendicular to the shear direction, which causes that the ellipsoidal particles with higher elongation are more aligned with the direction of the shear velocity, with more uniform force network. This then affects other particle properties. The fluctuation of linear velocity and the angular velocity decreases with an increase in particle aspect ratio, although the particle elongation does not significantly affect the flow velocity gradient. There is a reduction in both normal and tangential forces per contact with an increase of particle elongation. Due to the variation of the particle alignment with elongation, the standard deviation of the contact energies increases and then reduces when an increase in particle aspect ratio occurs, and on contrary, the porosity has an opposite variation trend.
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Affiliation(s)
- M Hossain
- School of Engineering, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - H P Zhu
- School of Engineering, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - A B Yu
- Faculty of Engineering, Monash University, 14 Alliance Lane (Engineering 72), Clayton Victoria 3168, Australia
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23
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Mowlavi S, Kamrin K. Interplay between hysteresis and nonlocality during onset and arrest of flow in granular materials. SOFT MATTER 2021; 17:7359-7375. [PMID: 34297021 DOI: 10.1039/d1sm00659b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The jamming transition in granular materials is well-known for exhibiting hysteresis, wherein the level of shear stress required to trigger flow is larger than that below which flow stops. Although such behavior is typically modeled as a simple non-monotonic flow rule, the rheology of granular materials is also nonlocal due to cooperativity at the grain scale, leading for instance to increased strengthening of the flow threshold as system size is reduced. We investigate how these two effects - hysteresis and nonlocality - couple with each other by incorporating non-monotonicity of the flow rule into the nonlocal granular fluidity (NGF) model, a nonlocal constitutive model for granular flows. By artificially tuning the strength of nonlocal diffusion, we demonstrate that both ingredients are key to explaining certain features of the hysteretic transition between flow and arrest. Finally, we assess the ability of the NGF model to quantitatively predict material behavior both around the transition and in the flowing regime, through stress-driven discrete element method (DEM) simulations of flow onset and arrest in various geometries. Along the way, we develop a new methodology to compare deterministic model predictions with the stochastic behavior exhibited by the DEM simulations around the jamming transition.
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Affiliation(s)
- Saviz Mowlavi
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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24
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Agarwal S, Karsai A, Goldman DI, Kamrin K. Efficacy of simple continuum models for diverse granular intrusions. SOFT MATTER 2021; 17:7196-7209. [PMID: 34269368 DOI: 10.1039/d1sm00130b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Granular intrusion is commonly observed in natural and human-made settings. Unlike typical solids and fluids, granular media can simultaneously display fluid-like and solid-like characteristics in a variety of intrusion scenarios. This multi-phase behavior increases the difficulty of accurately modeling these and other yielding (or flowable) materials. Micro-scale modeling methods, such as DEM (Discrete Element Method), capture this behavior by modeling the media at the grain scale, but there is often interest in the macro-scale characterizations of such systems. We examine the efficacy of a macro-scale continuum approach in modeling and understanding the physics of various macroscopic phenomena in a variety of granular intrusion cases using two basic frictional yielding constitutive models. We compare predicted granular force response and material flow to experimental data in four quasi-2D intrusion cases: (1) depth-dependent force response in horizontal submerged-intruder motion; (2) separation-dependent drag variation in parallel-plate vertical-intrusion; (3) initial-density-dependent drag fluctuations in free surface plowing, and (4) flow zone development during vertical plate intrusions in under-compacted granular media. Our continuum modeling approach captures the flow process and drag forces while providing key meso- and macro-scopic insights. The modeling results are then compared to experimental data. Our study highlights how continuum modeling approaches provide an alternative for efficient modeling as well as a conceptual understanding of various granular intrusion phenomena.
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Affiliation(s)
| | | | | | - Ken Kamrin
- Department of Mechanical Engineering, MIT, Cambridge, USA.
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25
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Abstract
In the field of granular rheology, an important open question is to understand the influence of boundary conditions on granular flows. We perform experiments in a quasi-2D annular shear cell subject to 6 different boundaries with controlled roughness/compliance. We characterize the granular slip at the boundaries to investigate which aspects of a dense granular flow can be controlled by the choice of boundary condition. Photoelastic techniques are implemented to measure the stress fields P(r) and τ(r) throughout the material. A full inverse-analysis of the fringes within each disk provides the vector force at each contact. This allows us to measure the continuum stress field by coarse-graining internal forces. We have observed that boundary roughness and compliance strongly controls the flow profile v(r) and shear rate profile γ˙(r). We also observed that boundary roughness and compliance play a significant role in the pressure profile P(r) and shear stress profile τ(r).
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26
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Faroux D, Washino K, Tsuji T, Tanaka T. Coupling non-local rheology and volume of fluid (VOF) method: a finite volume method (FVM) implementation. EPJ WEB OF CONFERENCES 2021. [DOI: 10.1051/epjconf/202124903025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Additional to a behavior switching between solid-like and liquid-like, dense granular flows also present propagating grain size-dependent effects also called non-local effects. Such behaviors cannot be efficiently modeled by standard rheologies such as µ(I)-rheology but have to be dealt with advanced non-local models. Unfortunately, these models are still new and cannot be used easily nor be used for various configurations. We propose in this work a FVM implementation of the recently popular NGF model coupled with the VOF method in order to both make non-local modeling more accessible to everyone and suitable not only for single-phase flows but also for two-phase flows. The proposed implementation has the advantage to be extremely straightforward and to only require a supplementary stabilization loop compared to the theoretical equations. We then applied our new framework to both single and two-phase flows for validation.
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27
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Tsai JCJ, Huang GH, Tsai CE. Signature of Transition between Granular Solid and Fluid: Rate-Dependent Stick Slips in Steady Shearing. PHYSICAL REVIEW LETTERS 2021; 126:128001. [PMID: 33834824 DOI: 10.1103/physrevlett.126.128001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 11/04/2020] [Accepted: 01/28/2021] [Indexed: 06/12/2023]
Abstract
Despite extensive studies on either smooth granular-fluid flow or the solidlike deformation at the slow limit, the change between these two extremes remains largely unexplored. By systematically investigating the fluctuations of tightly packed grains under steady shearing, we identify a transition zone with prominent stick-slip avalanches. We establish a state diagram, and propose a new dimensionless shear rate based on the speed dependence of interparticle friction and particle size. With fluid-immersed particles confined in a fixed volume and forced to "flow" at viscous numbers J decades below reported values, we answer how a granular system can transition to the regime sustained by solid-to-solid friction that goes beyond existing paradigms based on suspension rheology.
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Affiliation(s)
| | - Guan-Hao Huang
- Institute of Physics, Academia Sinica, 11529 Taipei, Taiwan
| | - Cheng-En Tsai
- Institute of Physics, Academia Sinica, 11529 Taipei, Taiwan
- Department of Physics, National Central University, 320317 Chung-Li, Taiwan
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28
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Madani M, Maleki M, Török J, Shaebani MR. Evolution of shear zones in granular packings under pressure. SOFT MATTER 2021; 17:1814-1820. [PMID: 33399618 DOI: 10.1039/d0sm01768j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Stress transmission in realistic granular media often occurs under external load and in the presence of boundary slip. We investigate shear localization in a split-bottom Couette cell with smooth walls subject to a confining pressure experimentally and by means of numerical simulations. We demonstrate how the characteristics of the shear zone, such as its center position and width, evolve as the confining pressure and wall slip modify the local effective friction coefficient of the material. For increasing applied pressure, the shear zone evolves toward the center of the cylinder and grows wider and the angular velocity reduces compared to the driving rate of the bottom disk. Moreover, the presence of slip promotes the transition from open shear zones at the top surface to closed shear zones inside the bulk. We also systematically vary the ratio of the effective friction near the bottom plate and in the bulk in simulations and observe the resulting impact on the surface flow profile. Besides the boundary conditions and external load, material properties such as grain size are also known to influence the effective friction coefficient. However, our numerical results reveal that the center position and width of the shear zone are insignificantly affected by the choice of the grain size as far as it remains small compared to the radius of the rotating bottom disk.
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Affiliation(s)
- Mahnoush Madani
- Department of Physics, Institute for Advanced Studies in Basic Sciences, Zanjan 45137-66731, Iran
| | - Maniya Maleki
- Department of Physics, Institute for Advanced Studies in Basic Sciences, Zanjan 45137-66731, Iran and Optics Research Center, Institute for Advanced Studies in Basic Sciences, Zanjan 45137-66731, Iran
| | - János Török
- MTA-BME Morphodynamics Research Group, Department of Theoretical Physics, Budapest University of Technology and Economics, Budapest H-1111, Hungary
| | - M Reza Shaebani
- Department of Theoretical Physics & Center for Biophysics, Saarland University, 66041 Saarbrücken, Germany.
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29
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Cabrera M, Polanía O. Heaps of sand in flows within a split-bottom Couette cell. Phys Rev E 2021; 102:062901. [PMID: 33466047 DOI: 10.1103/physreve.102.062901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 11/19/2020] [Indexed: 11/07/2022]
Abstract
In this paper, we study the flow of angular grains in a split-bottom Couette cell. Grains departing from a spherical shape result in collective flow fields that form a heap on the free surface. Here we extend on previous observations in split-bottom cells, exploring a wider range of flows within the inertial regime and finding a richness collection of behaviours. Surface height profiles and velocity profiles are accurately measured with digital image analysis. These measurements allow the characterization of the flow regimes within the cell and the heap morphology. We show that the known flow regimes in split-bottom geometries, like the universal and wall-collapsed regimes, can also be observed in moderately high inertial flows, extending the range for studying universal shear banding. The heap morphology is amplified by the flow inertia, with a partial collapse when the cell comes to a halt. Moreover, at high angular velocities, flows under low confinement will spread radially outwards, while flows under high confinement will develop localized particle ejections. Our results complement the observation of free-surface deformations of flows of nonspherical grains. These observations suggest a need for considering deformable free surface boundary conditions in the simulation of angular grains during shear, with repercussions in the characterization and prediction of natural mass flows.
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Affiliation(s)
- Miguel Cabrera
- Department of Civil and Environmental Engineering, Universidad de los Andes, Bogotá, Colombia
| | - Oscar Polanía
- Department of Civil and Environmental Engineering, Universidad de los Andes, Bogotá, Colombia
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30
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Jenkins J, Berzi D. Analytical solutions for dense, inclined, granular flow over a rigid, bumpy base. EPJ WEB OF CONFERENCES 2021. [DOI: 10.1051/epjconf/202124903039] [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
We first phrase a boundary-value problem for a dense, steady, fully-developed, gravitational flow of identical inelastic spheres over in inclined bumpy base in the absence of sidewalls. We then obtain approximate analytical solutions for the profiles of the solid volume fraction, the strength of the velocity fluctuations, and the mean velocity of the flow. We compare these with those obtained in numerical solutions of the exact equations.
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31
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Levy dit Vehel V, Hatano T, Vanel L, Måløy KJ, Ramos O. Dilation as a precursor in a continuous granular fault. EPJ WEB OF CONFERENCES 2021. [DOI: 10.1051/epjconf/202124915006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We analyze the dilation of the system in a cylindrical granular fault consisting of one single layer of disks submitted to both normal pressure and continuous and slow shear, which results in intermittent and sudden energy release events that reproduce the main laws of seismicity. The dilation of the system can be separated into two parts: a smooth increase of dilation, plus sudden changes both contracting and dilating the medium, which are correlated to abrupt jumps -both positive and negative- in the measured resisting torque. We explain the four possible (and existing) general scenarios combining those two variables: dilation jumps and torque jumps, thanks to the assumption of an optimal local angle in the direction of force chains, and each reorganization of the structure as a replacement of the force chain holding most of the applied stress. The average rate of increase of global dilation varies monotonically with the size of the energy release event, making dilation a plausible candidate to predict catastrophic events in such earthquake-like systems.
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32
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Robinson J, Holland D, Fullard L. Evidence of a non-local ø( I) response. EPJ WEB OF CONFERENCES 2021. [DOI: 10.1051/epjconf/202124903028] [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
Granular dilatancy has been previously characterised through a simple linear relationship between the packing fraction and dimensionless shear rate. However, this relationship was developed for granular flows in a simple shear cell geometry. Here we examine inertial volume changes in a shear cell with gravity, a vertical chute, and a pseudo-2D hopper. In so doing, we show that the packing fraction displays both a local and non-local response, analogous to what is typically observed for the stress ratio µ.
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33
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Gaume J, Chambon G, Naaim M. Microscopic Origin of Nonlocal Rheology in Dense Granular Materials. PHYSICAL REVIEW LETTERS 2020; 125:188001. [PMID: 33196218 DOI: 10.1103/physrevlett.125.188001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/07/2020] [Accepted: 09/23/2020] [Indexed: 06/11/2023]
Abstract
We study the microscopic origin of nonlocality in dense granular media. Discrete element simulations reveal that macroscopic shear results from a balance between microscopic elementary rearrangements occurring in opposite directions. The effective macroscopic fluidity of the material is controlled by these velocity fluctuations, which are responsible for nonlocal effects in quasistatic regions. We define a new micromechanically based unified constitutive law describing both quasistatic and inertial regimes, valid for different system configurations.
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Affiliation(s)
- Johan Gaume
- Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Guillaume Chambon
- Univ. Grenoble Alpes, INRAE, UR ETNA, 38402 St-Martin-d'Hères, France
| | - Mohamed Naaim
- Univ. Grenoble Alpes, INRAE, UR ETNA, 38402 St-Martin-d'Hères, France
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34
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Li S, Henann DL. Nonlocal continuum modeling of dense granular flow in a split-bottom cell with a vane-shaped intruder. Phys Rev E 2020; 102:022908. [PMID: 32942386 DOI: 10.1103/physreve.102.022908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/03/2020] [Indexed: 11/07/2022]
Abstract
Shear flow in one spatial region of a dense granular material-induced, for example, through the motion of a boundary-fluidizes the entire granular material. One consequence is that the yield condition vanishes throughout the granular material-even in regions that are very far from the "primary," boundary-driven shear flow. This phenomenon may be characterized through the mechanics of intruders embedded in the granular medium. When there is no primary flow, a critical load must be exceeded to move the intruder; however, in the presence of a primary flow, intruder motion occurs even when an arbitrarily small external load is applied to an intruder embedded in a region far from the sheared zone. In this paper, we apply the nonlocal granular fluidity (NGF) model-a continuum model that involves higher-order flow gradients-to simulate the specific case of dense flow in a split-bottom cell with a vane-shape intruder. Our simulations quantitatively capture the key features of the experimentally observed phenomena: (1) the vanishing of the yield condition, (2) an exponential-type relationship between the applied torque and the rotation rate, (3) the effect of the distance between the intruder and the primary flow zone, and (4) the direction-dependence of the torque/rotation-rate relation, in which the observed relation changes depending on whether the intruder is forced to rotate along with or counter to the primary flow. Importantly, this represents the first fully three-dimensional validation test for a nonlocal model for dense granular flow in general and for the NGF model in particular.
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Affiliation(s)
- Shihong Li
- School of Engineering, Brown University, Providence, Rhode Island 02912, USA
| | - David L Henann
- School of Engineering, Brown University, Providence, Rhode Island 02912, USA
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35
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Coquand O, Sperl M, Kranz WT. Integration through transients approach to the μ(I) rheology. Phys Rev E 2020; 102:032602. [PMID: 33075983 DOI: 10.1103/physreve.102.032602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
This work generalizes the granular integration through transients formalism introduced by Kranz et al. [Phys. Rev. Lett. 121, 148002 (2018)10.1103/PhysRevLett.121.148002] to the determination of the pressure. We focus on the Bagnold regime and provide theoretical support to the empirical μ(I) rheology laws that have been successfully applied in many granular flow problems. In particular, we confirm that the interparticle friction is irrelevant in the regime where the μ(I) laws apply.
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Affiliation(s)
- O Coquand
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
| | - M Sperl
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
- Institut für Theoretische Physik, Universität zu Köln, 50937 Köln, Germany
| | - W T Kranz
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany
- Institut für Theoretische Physik, Universität zu Köln, 50937 Köln, Germany
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36
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Kim S, Kamrin K. Power-Law Scaling in Granular Rheology across Flow Geometries. PHYSICAL REVIEW LETTERS 2020; 125:088002. [PMID: 32909790 DOI: 10.1103/physrevlett.125.088002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 07/17/2020] [Indexed: 06/11/2023]
Abstract
Based on discrete element method simulations, we propose a new form of the constitutive equation for granular flows independent of packing fraction. Rescaling the stress ratio μ by a power of dimensionless temperature Θ makes the data from a wide set of flow geometries collapse to a master curve depending only on the inertial number I. The basic power-law structure appears robust to varying particle properties (e.g., surface friction) in both 2D and 3D systems. We show how this rheology fits and extends frameworks such as kinetic theory and the nonlocal granular fluidity model.
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Affiliation(s)
- Seongmin Kim
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Ken Kamrin
- Department of Mechanical Engineering, MIT, Cambridge, Massachusetts 02139, USA
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37
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Wu K, Francia V, Coppens MO. Dynamic viscoplastic granular flows: A persistent challenge in gas-solid fluidization. POWDER TECHNOL 2020. [DOI: 10.1016/j.powtec.2019.04.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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38
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Remmelgas J, Fall A, Sasic S, Ström H, Tajarobi P, Wikström H, Marucci M, Boissier C. Characterization of microcrystalline cellulose spheres and prediction of hopper flow based on a μ(I)-rheology model. Eur J Pharm Sci 2020; 142:105085. [PMID: 31669423 DOI: 10.1016/j.ejps.2019.105085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/29/2019] [Accepted: 09/18/2019] [Indexed: 11/26/2022]
Abstract
The objective of this study was to characterize the rheology of a pharmaceutical material in the context of the µ(I)-rheology model and to use this model to predict powder flow in a manufacturing operation that is relevant to pharmaceutical manufacturing. The rheology of microcrystalline cellulose spheres was therefore characterized in terms of the μ(I)-rheology model using a modified Malvern Kinexus rheometer. As an example of an important problem in pharmaceutical manufacturing, the flow of these particles from a hopper was studied experimentally and numerically using a continuum Navier-Stokes solver based on the Volume-Of-Fluid (VOF) interface-capturing numerical method. The work shows that the rheology of this typical pharmaceutical material can be measured using a modified annular shear rheometer and that the results can be interpreted in terms of the μ(I)-rheology model. It is demonstrated that both the simulation results and the experimental data show a constant hopper discharge rate. It is noted that the model can suffer from ill-posedness and it is shown how an increasingly fine grid resolution can result in predictions that are not entirely physically realistic. This shortcoming of the numerical framework implies that caution is required when making a one-to-one comparison with experimental data.
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Affiliation(s)
- Johan Remmelgas
- Global Product Development, Pharmaceutical Technology & Development, AstraZeneca, Gothenburg, Sweden.
| | - Abdoulaye Fall
- Université Paris Est, Laboratoire Navier (UMR 8205 CNRS, IFSTTAR, Ecole des Ponts ParisTech), Champs-sur-Marne, France
| | - Srdjan Sasic
- Chalmers University of Technology, Department of Mechanics and Maritime Sciences, Gothenburg, Sweden
| | - Henrik Ström
- Chalmers University of Technology, Department of Mechanics and Maritime Sciences, Gothenburg, Sweden
| | - Pirjo Tajarobi
- Pharmaceutical Sciences, Biopharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Håkan Wikström
- Global Product Development, Pharmaceutical Technology & Development, AstraZeneca, Gothenburg, Sweden
| | - Mariagrazia Marucci
- Global Product Development, Pharmaceutical Technology & Development, AstraZeneca, Gothenburg, Sweden
| | - Catherine Boissier
- Pharmaceutical Sciences, Biopharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
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39
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Xu T, Jin YC, Tai YC. Granular surface waves interaction across phases modeled by mesh-free method. POWDER TECHNOL 2019. [DOI: 10.1016/j.powtec.2019.07.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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40
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Lherminier S, Planet R, Vehel VLD, Simon G, Vanel L, Måløy KJ, Ramos O. Continuously Sheared Granular Matter Reproduces in Detail Seismicity Laws. PHYSICAL REVIEW LETTERS 2019; 122:218501. [PMID: 31283309 DOI: 10.1103/physrevlett.122.218501] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Indexed: 06/09/2023]
Abstract
We introduce a shear experiment that quantitatively reproduces the main laws of seismicity. By continuously and slowly shearing a compressed monolayer of disks in a ringlike geometry, our system delivers events of frictional failures with energies following a Gutenberg-Richter law. Moreover, foreshocks and aftershocks are described by Omori laws and interevent times also follow exactly the same distribution as real earthquakes, showing the existence of memory of past events. Other features of real earthquakes qualitatively reproduced in our system are both the existence of a quiescence preceding some main shocks, as well as magnitude correlations linked to large quakes. The key ingredient of the dynamics is the nature of the force network, governing the distribution of frictional thresholds.
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Affiliation(s)
- S Lherminier
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon 69622 Villeurbanne, France
| | - R Planet
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon 69622 Villeurbanne, France
| | - V Levy Dit Vehel
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon 69622 Villeurbanne, France
| | - G Simon
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon 69622 Villeurbanne, France
| | - L Vanel
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon 69622 Villeurbanne, France
| | - K J Måløy
- PoreLab, The Njord Centre, Department of Physics, University of Oslo, P. O. Box 1048, 0316 Oslo, Norway
| | - O Ramos
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon 69622 Villeurbanne, France
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41
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Saitoh K, Tighe BP. Nonlocal Effects in Inhomogeneous Flows of Soft Athermal Disks. PHYSICAL REVIEW LETTERS 2019; 122:188001. [PMID: 31144889 DOI: 10.1103/physrevlett.122.188001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Indexed: 06/09/2023]
Abstract
We numerically investigate nonlocal effects on inhomogeneous flows of soft athermal disks close to but below their jamming transition. We employ molecular dynamics to simulate Kolmogorov flows, in which a sinusoidal flow profile with fixed wave number is externally imposed, resulting in a spatially inhomogeneous shear rate. We find that the resulting rheology is strongly wave-number-dependent, and that particle migration, while present, is not sufficient to describe the resulting stress profiles within a conventional local model. We show that, instead, stress profiles can be captured with nonlocal constitutive relations that account for gradients to fourth order. Unlike nonlocal flow in yield stress fluids, we find no evidence of a diverging length scale.
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Affiliation(s)
- Kuniyasu Saitoh
- Research Alliance Center for Mathematical Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- WPI-Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Brian P Tighe
- Delft University of Technology, Process and Energy Laboratory, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands
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42
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Tang Y, Zhang L, Guo Q, Xia B, Yin Z, Cao J, Tong J, Rycroft CH. Analysis of the pebble burnup profile in a pebble-bed nuclear reactor. NUCLEAR ENGINEERING AND DESIGN 2019. [DOI: 10.1016/j.nucengdes.2019.01.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
Accurate continuum models of flow and segregation of dense granular flows are now possible. This is the result of extensive comparisons, over the last several years, of computer simulations of increasing accuracy and scale, experiments, and continuum models, in a variety of flows and for a variety of mixtures. Computer simulations-discrete element methods (DEM)-yield remarkably detailed views of granular flow and segregation. Conti-nuum models, however, offer the best possibility for parametric studies of outcomes in what could be a prohibitively large space resulting from the competition between three distinct driving mechanisms: advection, diffusion, and segregation. We present a continuum transport equation-based framework, informed by phenomenological constitutive equations, that accurately predicts segregation in many settings, both industrial and natural. Three-way comparisons among experiments, DEM, and theory are offered wherever possible to validate the approach. In addition to the flows and mixtures described here, many straightforward extensions of the framework appear possible.
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Affiliation(s)
- Paul B Umbanhowar
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208, USA;
| | - Richard M Lueptow
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208, USA; .,Department of Chemical and Biological Engineering and the Northwestern Institute on Complex Systems, Northwestern University, Evanston, Illinois 60208, USA
| | - Julio M Ottino
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208, USA; .,Department of Chemical and Biological Engineering and the Northwestern Institute on Complex Systems, Northwestern University, Evanston, Illinois 60208, USA
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44
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Roy S, Scheper BJ, Polman H, Thornton AR, Tunuguntla DR, Luding S, Weinhart T. Surface flow profiles for dry and wet granular materials by Particle Tracking Velocimetry; the effect of wall roughness. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2019; 42:14. [PMID: 30756195 DOI: 10.1140/epje/i2019-11778-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 01/04/2019] [Indexed: 06/09/2023]
Abstract
Two-dimensional Particle Tracking Velocimetry (PTV) is a promising technique to study the behaviour of granular flows. The aim is to experimentally determine the free surface width and position of the shear band from the velocity profile to validate simulations in a split-bottom shear cell geometry. The position and velocities of scattered tracer particles are tracked as they move with the bulk flow by analyzing images. We then use a new technique to extract the continuum velocity field, applying coarse-graining with the postprocessing toolbox MercuryCG on the discrete experimental PTV data. For intermediate filling heights, the dependence of the shear (or angular) velocity on the radial coordinate at the free surface is well fitted by an error function. From the error function, we get the width and the centre position of the shear band. We investigate the dependence of these shear band properties on filling height and rotation frequencies of the shear cell for dry glass beads for rough and smooth wall surfaces. For rough surfaces, the data agrees with the existing experimental results and theoretical scaling predictions. For smooth surfaces, particle-wall slippage is significant and the data deviates from the predictions. We further study the effect of cohesion on the shear band properties by using small amount of silicon oil and glycerol as interstitial liquids with the glass beads. While silicon oil does not lead to big changes, glycerol changes the shear band properties considerably. The shear band gets wider and is situated further inward with increasing liquid saturation, due to the correspondingly increasing trend of particles to stick together.
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Affiliation(s)
- Sudeshna Roy
- Multi-Scale Mechanics, Engineering Technology (ET) and MESA + University of Twente, 7500, AE Enschede, The Netherlands.
| | - Bert J Scheper
- Multi-Scale Mechanics, Engineering Technology (ET) and MESA + University of Twente, 7500, AE Enschede, The Netherlands
| | - Harmen Polman
- Multi-Scale Mechanics, Engineering Technology (ET) and MESA + University of Twente, 7500, AE Enschede, The Netherlands
| | - Anthony R Thornton
- Multi-Scale Mechanics, Engineering Technology (ET) and MESA + University of Twente, 7500, AE Enschede, The Netherlands
| | - Deepak R Tunuguntla
- Multi-Scale Mechanics, Engineering Technology (ET) and MESA + University of Twente, 7500, AE Enschede, The Netherlands
| | - Stefan Luding
- Multi-Scale Mechanics, Engineering Technology (ET) and MESA + University of Twente, 7500, AE Enschede, The Netherlands
| | - Thomas Weinhart
- Multi-Scale Mechanics, Engineering Technology (ET) and MESA + University of Twente, 7500, AE Enschede, The Netherlands
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45
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Fullard LA, Breard ECP, Davies CE, Godfrey AJR, Fukuoka M, Wade A, Dufek J, Lube G. The dynamics of granular flow from a silo with two symmetric openings. Proc Math Phys Eng Sci 2019; 475:20180462. [PMID: 30760953 DOI: 10.1098/rspa.2018.0462] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/29/2018] [Indexed: 12/30/2022] Open
Abstract
The dynamics of granular flow in a rectangular silo with two symmetrically placed exit openings is investigated using particle image velocimetry (PIV), flow rate measurements and discrete element modelling (DEM). The flow of mustard seeds in a Perspex silo is recorded using a high-speed camera and the resulting image frames are analysed using PIV to obtain velocity, velocity divergence and shear rate plots. A change in flow structure is observed as the distance L between the two openings is varied. The mass flow rate is shown to be at a maximum at zero opening separation, decreasing as L is increased; it then reaches a minimum before rising to an equilibrium rate close to two times that of an isolated (non-interacting) opening. The flow rate experiment is repeated using amaranth and screened sand and similar behaviour is observed. Although this result is in contrast with some recent DEM and physical experiments in silo systems, this effect has been reported in an analogous system: the evacuation of pedestrians from a room through two doors. Our experimental results are replicated using DEM and we show that inter-particle friction controls the flow rate behaviour and explains the discrepancies in the literature results.
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Affiliation(s)
- L A Fullard
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - E C P Breard
- Department of Earth Sciences, University of Oregon, Eugene, OR, USA
| | - C E Davies
- School of Engineering and Advanced Technology, Massey University, Palmerston North, New Zealand
| | - A J R Godfrey
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - M Fukuoka
- School of Engineering and Advanced Technology, Massey University, Palmerston North, New Zealand
| | - A Wade
- School of Engineering and Advanced Technology, Massey University, Palmerston North, New Zealand
| | - J Dufek
- Department of Earth Sciences, University of Oregon, Eugene, OR, USA
| | - G Lube
- Volcanic Risk Solutions, Massey University, Palmerston North, New Zealand
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Zheng J, Sun A, Wang Y, Zhang J. Energy Fluctuations in Slowly Sheared Granular Materials. PHYSICAL REVIEW LETTERS 2018; 121:248001. [PMID: 30608758 DOI: 10.1103/physrevlett.121.248001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Indexed: 06/09/2023]
Abstract
Here we show the first experimental measurement of the particle-scale energy fluctuations ΔE in a slowly sheared layer of photoelastic disks. Starting from an isotropically jammed state, applying shear causes the shear-induced stochastic strengthening and weakening of particle-scale energies, whose statistics and dynamics govern the evolution of the macroscopic stress-strain curve. We find that the ΔE behave as a temperaturelike noise field, showing a novel, Boltzmann-type, double-exponential distribution at any given shear strain γ. Following the framework of the soft glassy rheology theory, we extract an effective temperature χ from the statistics of the energy fluctuations to interpret the slow startup shear (shear starts from an isotropically jammed state) of granular materials as an "aging" process: Starting below one, χ gradually approaches one as γ increases, similar to those of spin glasses, thermal glasses, and bulk metallic glasses.
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Affiliation(s)
- Jie Zheng
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Aile Sun
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yujie Wang
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jie Zhang
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
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47
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Itoh R, Hatano T. Geological implication of grain-size segregation in dense granular matter. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 377:rsta.2017.0390. [PMID: 30478202 PMCID: PMC6282402 DOI: 10.1098/rsta.2017.0390] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 08/15/2018] [Indexed: 06/09/2023]
Abstract
To the current common belief, grain size segregation in granular matter requires sufficient porosity. Therefore, grain size segregation found in a natural fault gouge could imply elevated fluid pressure and the reduced normal stress on fault, possibly caused by the frictional heat during an earthquake. To clarify whether fluidization is essential to grain size segregation, we conduct numerical simulation on a simple model of fault gouge in a plane shear geometry under constant volume condition: the volume fraction is fixed at 0.6, at which the granular system possesses yield stress. We observe apparent grain size segregation at this volume fraction, meaning that grain size segregation alone does not imply fluidization of granular matter. We also show that segregation is driven by the nonlinear velocity profile, and that the gravity is not essential to segregation. The physical condition tested here may be relevant to earthquake faults: the normal stress of 1 MPa, the sliding velocity of 1 m s-1, and the duration of 0.1 s.This article is part of the theme issue 'Statistical physics of fracture and earthquakes'.
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Affiliation(s)
- Ryo Itoh
- Dia Consultants Co. Ltd., 2-272-3 Yoshinocho, Kita-ku, Saitama 331-0811, Japan
| | - Takahiro Hatano
- Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-0032, Japan
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48
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Ma X, Elbanna A. Strain localization in dry sheared granular materials: A compactivity-based approach. Phys Rev E 2018; 98:022906. [PMID: 30253526 DOI: 10.1103/physreve.98.022906] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Indexed: 11/07/2022]
Abstract
Shear banding is widely observed in natural fault zones as well as in laboratory experiments on granular materials. Understanding the dynamics of strain localization under different loading conditions is essential for quantifying strength evolution of fault gouge and energy partitioning during earthquakes and characterizing rheological transitions and fault zone structure changes. To that end, we develop a physics-based continuum model for strain localization in sheared granular materials. The grain-scale dynamics is described by the shear transformation zone (STZ) theory, a nonequilibrium statistical thermodynamic framework for viscoplastic deformation in amorphous materials. Using a finite strain computational framework, we investigate the initiation and growth of complex shear bands under a variety of loading conditions and identify implications for strength evolution and the ductile to brittle transition. Our numerical results show similar localization patterns to field and laboratory observations and suggest that shear zones show more ductile response at higher confining pressures, lower dilatancy, and loose initial conditions. Lower pressures, higher dilatancy, and dense initial conditions favor a brittle response and larger strength drops. These findings shed light on a range of mechanisms for strength evolution in dry sheared granular materials and provide a critical input to physics-based multiscale models of fault zone instabilities.
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Affiliation(s)
- Xiao Ma
- Department of Civil and Environmental Engineering, University of Illinois, Urbana-Champaign, Illinois, USA
| | - Ahmed Elbanna
- Department of Civil and Environmental Engineering, University of Illinois, Urbana-Champaign, Illinois, USA
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49
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Houdoux D, Nguyen TB, Amon A, Crassous J. Plastic flow and localization in an amorphous material: Experimental interpretation of the fluidity. Phys Rev E 2018; 98:022905. [PMID: 30253465 DOI: 10.1103/physreve.98.022905] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Indexed: 11/06/2022]
Abstract
We present a thorough study of the plastic response of a granular material progressively loaded. We study experimentally the evolution of the plastic field from a homogeneous one to a heterogeneous one and its fluctuations in terms of incremental strain. We show that the plastic field can be decomposed in two components evolving on two decoupled strain increment scales. We argue that the slowly varying part of the field can be identified with the so-called fluidity field introduced recently to interpret the rheological behavior of amorphous materials. This fluidity field progressively concentrates along a macroscopic direction corresponding to the Mohr-Coulomb angle.
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Affiliation(s)
- David Houdoux
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - Thai Binh Nguyen
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - Axelle Amon
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - Jérôme Crassous
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
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50
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Czajkowski M, Bi D, Manning ML, Marchetti MC. Hydrodynamics of shape-driven rigidity transitions in motile tissues. SOFT MATTER 2018; 14:5628-5642. [PMID: 29938290 DOI: 10.1039/c8sm00446c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In biological tissues, it is now well-understood that mechanical cues are a powerful mechanism for pattern regulation. While much work has focused on interactions between cells and external substrates, recent experiments suggest that cell polarization and motility might be governed by the internal shear stiffness of nearby tissue, deemed "plithotaxis". Meanwhile, other work has demonstrated that there is a direct relationship between cell shapes and tissue shear modulus in confluent tissues. Joining these two ideas, we develop a hydrodynamic model that couples cell shape, and therefore tissue stiffness, to cell motility and polarization. Using linear stability analysis and numerical simulations, we find that tissue behavior can be tuned between largely homogeneous states and patterned states such as asters, controlled by a composite "morphotaxis" parameter that encapsulates the nature of the coupling between shape and polarization. The control parameter is in principle experimentally accessible, and depends both on whether a cell tends to move in the direction of lower or higher shear modulus, and whether sinks or sources of polarization tend to fluidize the system.
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