1
|
Why the presence of insert above the outlet can enhance silo discharge: A tentative answer. POWDER TECHNOL 2023. [DOI: 10.1016/j.powtec.2023.118384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
|
2
|
Liu HK, Shi ZH, Li WF, Liu HF, Wang FC. Asymmetric oscillation of pressurized dense gas-solid jet in a two-dimensional nozzle. POWDER TECHNOL 2021. [DOI: 10.1016/j.powtec.2021.07.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
3
|
Gao GJJ, Yang FL, Holcomb MC, Blawzdziewicz J. Enhanced flow rate by the concentration mechanism of Tetris particles when discharged from a hopper with an obstacle. Phys Rev E 2021; 103:062904. [PMID: 34271757 DOI: 10.1103/physreve.103.062904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 05/13/2021] [Indexed: 11/07/2022]
Abstract
We apply a holistic two-dimensional (2D) Tetris-like model, where particles move based on prescribed rules, to investigate the flow rate enhancement from a hopper. This phenomenon was originally reported in the literature as a feature of placing an obstacle at an optimal location near the exit of a hopper discharging athermal granular particles under gravity. We find that this phenomenon is limited to a system of sufficiently many particles. In addition to the waiting room effect, another mechanism able to explain and create the flow rate enhancement is the concentration mechanism of particles on their way to reaching the hopper exit after passing the obstacle. We elucidate the concentration mechanism by decomposing the flow rate into its constituent variables: the local area packing fraction ϕ_{l}^{E} and the averaged particle velocity v_{y}^{E} at the hopper exit. In comparison to the case without an obstacle, our results show that an optimally placed obstacle can create a net flow rate enhancement of relatively weakly driven particles, caused by the exit-bottleneck coupling if ϕ_{l}^{E}>ϕ_{o}^{c}, where ϕ_{o}^{c} is a characteristic area packing fraction marking a transition from fast to slow flow regimes of Tetris particles. Utilizing the concentration mechanism by artificially guiding particles into the central sparse space under the obstacle or narrowing the hopper exit angle under the obstacle, we can create a manmade flow rate peak of relatively strongly driven particles that initially exhibit no flow rate peak. Additionally, the enhanced flow rate can be maximized by an optimal obstacle shape, particle acceleration rate toward the hopper exit, or exit geometry of the hopper.
Collapse
Affiliation(s)
- Guo-Jie Jason Gao
- Department of Mathematical and Systems Engineering, Shizuoka University, Hamamatsu, Shizuoka 432-8561, Japan
| | - Fu-Ling Yang
- Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Michael C Holcomb
- Department of Physics and Geosciences, Angelo State University, San Angelo, Texas 76909-0904, USA
| | - Jerzy Blawzdziewicz
- Department of Physics and Astronomy, Texas Tech University, Lubbock, Texas 79409-1051, USA.,Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409-1021, USA
| |
Collapse
|
4
|
Kneib F, Faug T, Dufour F, Naaim M. Mean force and fluctuations on a wall immersed in a sheared granular flow. Phys Rev E 2019; 99:052901. [PMID: 31212502 DOI: 10.1103/physreve.99.052901] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Indexed: 11/07/2022]
Abstract
In a sheared and confined granular flow, the mean force and the force fluctuations on a rigid wall are studied by means of numerical simulations based on the discrete element method. An original periodic immersed-wall system is designed to investigate a wide range of confinement pressure and shearing velocity imposed at the top of the flow, considering different obstacle heights. The mean pressure on the wall relative to the confinement pressure is found to be a monotonic function of the boundary macroscopic inertial number which encapsulates the confinement pressure, the shearing velocity, and the thickness of the sheared layer above the wall. The one-to-one relation is slightly affected by the length of the granular system. The force fluctuations on the wall are quantified through the analysis of both the distributions of grain-wall contact forces and the autocorrelation of force time series. The distributions narrow as the boundary macroscopic inertial number decreases, moving from asymmetric log-normal shape to nearly Gaussian-type shape. That evolution of the grain-wall force distributions is accompanied at the lowest inertial numbers by the occurrence of a system memory in terms of the force transmitted to the wall, provided that the system length is not too large. Moreover, the distributions of grain-wall contact forces are unchanged when the inertial number is increased above a critical value. All those results allow to clearly identify the transitions from quasistatic to dense inertial, and from dense inertial to collisional, granular flow regimes.
Collapse
Affiliation(s)
- François Kneib
- Université Grenoble Alpes, Irstea, UR ETGR, 38000 Grenoble, France
| | - Thierry Faug
- Université Grenoble Alpes, Irstea, UR ETGR, 38000 Grenoble, France
| | - Frédéric Dufour
- Université Grenoble Alpes, CNRS, INP-Institute of Engineering Université Grenoble Alpes, 3SR, 38000 Grenoble, France
| | - Mohamed Naaim
- Université Grenoble Alpes, Irstea, UR ETGR, 38000 Grenoble, France
| |
Collapse
|
5
|
Kneib F, Faug T, Nicolet G, Eckert N, Naaim M, Dufour F. Force fluctuations on a wall in interaction with a granular lid-driven cavity flow. Phys Rev E 2017; 96:042906. [PMID: 29347536 DOI: 10.1103/physreve.96.042906] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Indexed: 06/07/2023]
Abstract
The force fluctuations experienced by a boundary wall subjected to a lid-driven cavity flow are investigated by means of numerical simulations based on the discrete-element method. The time-averaged dynamics inside the cavity volume and the resulting steady force on the wall are governed by the boundary macroscopic inertial number, the latter being derived from the shearing velocity and the confinement pressure imposed at the top. The force fluctuations are quantified through measuring both the autocorrelation of force time series and the distributions of grain-wall forces, at distinct spatial scales from particle scale to wall scale. A key result is that the grain-wall force distributions are entirely driven by the boundary macroscopic inertial number, whatever the spatial scale considered. In particular, when the wall scale is considered, the distributions are found to evolve from nearly exponential to nearly Gaussian distributions by decreasing the macroscopic inertial number. The transition from quasistatic to dense inertial flow is well identified through remarkable changes in the shapes of the distributions of grain-wall forces, accompanied by a loss of system memory in terms of the mesoscale force transmitted toward the wall.
Collapse
Affiliation(s)
- François Kneib
- Université Grenoble Alpes, Irstea, ETGR, 38402 St-Martin-d'Hères, France
| | - Thierry Faug
- Université Grenoble Alpes, Irstea, ETGR, 38402 St-Martin-d'Hères, France
| | - Gilles Nicolet
- Université Grenoble Alpes, Irstea, ETGR, 38402 St-Martin-d'Hères, France
| | - Nicolas Eckert
- Université Grenoble Alpes, Irstea, ETGR, 38402 St-Martin-d'Hères, France
| | - Mohamed Naaim
- Université Grenoble Alpes, Irstea, ETGR, 38402 St-Martin-d'Hères, France
| | - Frédéric Dufour
- Université Grenoble Alpes, CNRS, 3SR, F-38000 Grenoble, France
| |
Collapse
|
6
|
Clara-Rahola J, Puertas AM, Sánchez-Granero MA, Trinidad-Segovia JE, de Las Nieves FJ. Diffusive and Arrestedlike Dynamics in Currency Exchange Markets. PHYSICAL REVIEW LETTERS 2017; 118:068301. [PMID: 28234526 DOI: 10.1103/physrevlett.118.068301] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Indexed: 06/06/2023]
Abstract
This work studies the symmetry between colloidal dynamics and the dynamics of the Euro-U.S. dollar currency exchange market (EURUSD). We consider the EURUSD price in the time range between 2001 and 2015, where we find significant qualitative symmetry between fluctuation distributions from this market and the ones belonging to colloidal particles in supercooled or arrested states. In particular, we find that models used for arrested physical systems are suitable for describing the EURUSD fluctuation distributions. Whereas the corresponding mean-squared price displacement (MSPD) to the EURUSD is diffusive for all years, when focusing in selected time frames within a day, we find a two-step MSPD when the New York Stock Exchange market closes, comparable to the dynamics in supercooled systems. This is corroborated by looking at the price correlation functions and non-Gaussian parameters and can be described by the theoretical model. We discuss the origin and implications of this analogy.
Collapse
Affiliation(s)
- J Clara-Rahola
- Department of Applied Physics, University of Almería, 04120 Almería, Spain
- i2TiC Multidisciplinary Research Group, Open University of Catalonia, 08035 Barcelona, Spain
| | - A M Puertas
- Department of Applied Physics, University of Almería, 04120 Almería, Spain
| | | | - J E Trinidad-Segovia
- Department of Economics and Business, University of Almería, 04120 Almería, Spain
| | - F J de Las Nieves
- Department of Applied Physics, University of Almería, 04120 Almería, Spain
| |
Collapse
|
7
|
Kneib F, Faug T, Dufour F, Naaim M. Force fluctuations experienced by a boundary wall subjected to a granular
flow in two distinct systems. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201714003029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
8
|
|
9
|
Jia X, Gui N, Yang X, Tu J, Jiang S. Fluctuation and arching formation of very dense and slow pebble flow in a silo bed. J NUCL SCI TECHNOL 2016. [DOI: 10.1080/00223131.2016.1213671] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
10
|
Malkin AY, Kulichikhin VG. Structure and rheology of highly concentrated emulsions: a modern look. RUSSIAN CHEMICAL REVIEWS 2015. [DOI: 10.1070/rcr4499] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
11
|
Chen D, Desmond KW, Weeks ER. Experimental observation of local rearrangements in dense quasi-two-dimensional emulsion flow. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:062306. [PMID: 26172718 DOI: 10.1103/physreve.91.062306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Indexed: 06/04/2023]
Abstract
We experimentally study rearranging regions in slow athermal flow by observing the flow of a concentrated oil-in-water emulsion in a thin chamber with a constricting hopper shape. The gap of the chamber is smaller than the droplet diameters, so that the droplets are compressed into quasi-two-dimensional pancakes. We focus on localized rearrangements known as "T1 events" where four droplets exchange neighbors. Flowing droplets are deformed due to forces from neighboring droplets, and these deformations are decreased by nearby T1 events, with a spatial dependence related to the local structure. We see a tendency of the T1 events to occur in small clusters.
Collapse
Affiliation(s)
- Dandan Chen
- School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, China
- Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Suzhou, China
| | - Kenneth W Desmond
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| | - Eric R Weeks
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
| |
Collapse
|
12
|
Malkin A, Semakov A, Kulichikhin V. Self-organization in the flow of complex fluids (colloid and polymer systems): part 1: experimental evidence. Adv Colloid Interface Sci 2010; 157:75-90. [PMID: 20452569 DOI: 10.1016/j.cis.2010.04.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Revised: 04/06/2010] [Accepted: 04/09/2010] [Indexed: 10/19/2022]
Abstract
Different types of regular and irregular self-organized structures observed in deformation of colloid and polymer substances ("complex fluids") are discussed and classified. This review is focused on experimental evidence of structure formation and self-organization in shear flows, which have many similar features in systems of different types. For single-phase (uniform) polymer systems regular periodic surface structures are observed. Two main types of these structures are possible: small-scale regular screw-like periodic structures along the whole stream (usually called "shark-skin") and long-period smooth and distorted parts of a stream attributed as a "stick-slip" effect. The origin of surface irregularities of both types is elasticity of a liquid. In the limiting case of high enough Weissenberg numbers, medium loses fluidity and should be treated as a rubbery matter. The liquid-to-rubbery transition at high Weissenberg numbers is considered as the dominating mechanism of instability, leading in particular to the wall slip and rupture of a stream. Secondary flows ("vorticity") in deformation polymeric substances and complex fluids are also obliged to their elasticity and the observed Couette-Taylor-like cells, though being similar to well-known inertial secondary flows, are completely determined by elasticity of colloid and polymeric systems. In deformation of colloidal systems, suspensions and other dense concentrated heterophase materials, structure formation takes place at rest and the destroying of the structure happens as the yield stress. In opposite to this case, strong deformations can lead to the shear-induced structure formation and jamming. These effects are of general meaning for any complex fluids as well as for dense suspensions and granular media. Strong deformations also lead to separation of a stream into different parts (several "bands") with various properties of liquids in these parts. So, two principal effects common for any polymers and complex fluids can be pointed at as the physical origin of self-organization in shearing. This is elasticity of a liquid and a possibility of its existence in different phases or relaxation states, while in many cases elasticity of a fluid is considered as the most important provoking factor for transitions between different types of rheological behavior, e.g. the fluid-to-rubbery-like behavior at high deformation rates and the transition from the real laminar flow to wall slip.
Collapse
|
13
|
Cates ME, Poon WCK, Bartlett P. Colloids, grains and dense suspensions: under flow and under arrest. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2009; 367:4989-4991. [PMID: 19933123 DOI: 10.1098/rsta.2009.0201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Affiliation(s)
- Michael E Cates
- School of Physics and Astronomy, University of Edinburgh, JCMB Kings Buildings, Edinburgh, UK.
| | | | | |
Collapse
|
14
|
Haw MD. Volume fraction variations and dilation in colloids and granulars. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2009; 367:5167-5170. [PMID: 19933134 DOI: 10.1098/rsta.2009.0182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
I discuss the importance of spatial and temporal variations in particle volume fraction to understanding the force response of concentrated colloidal suspensions and granular materials.
Collapse
Affiliation(s)
- M D Haw
- Chemical and Process Engineering, University of Strathclyde, Glasgow, UK.
| |
Collapse
|