Numerical model for granular compaction under vertical tapping

Philippe, Pierre; Bideau, Daniel

doi:10.1103/physreve.63.051304

Cited by 65 publications

(54 citation statements)

References 28 publications

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“…Second, at high packing density, the excluded volume, and the associated cage effect, is very similar to the one observed in structural glasses [12]. A number of schematic lattice-gas models [13,14,15,16,17,18,19] has shown indeed that the main features of irreversible compaction do not depend, to a certain extent, on the dissipation mechanism (which is often assumed to be, for simplicity, of thermal nature), but can be understood solely in terms of steric hindrance. In this paper, we shall be concerned precisely with this quasi-static flow regime, which in the case of dense systems is the relevant one.…”

Section: Introductionmentioning

confidence: 84%

Slow dynamics under gravity: a nonlinear diffusion model

Arenzon

Levin

Sellitto

2003

Physica A: Statistical Mechanics and its Applications

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We present an analytical and numerical study of a nonlinear diffusion model which describes density relaxation of loosely packed particles under gravity and weak random (thermal) vibration, and compare the results with Monte Carlo simulations of a lattice gas under gravity. The dynamical equation can be thought of as a local density functional theory for a class of lattice gases used to model slow relaxation of glassy and granular materials. The theory predicts a jamming transition line between a low density fluid phase and a high density glassy regime, characterized by diverging relaxation time and logarithmic or power-law compaction according to the specific form of the diffusion coefficient. In particular, we show that the model exhibits history dependent properties, such as quasi reversible-irreversible cycle and memory effects -as observed in recent experiments, and dynamical heterogeneities.

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Section: Introductionmentioning

confidence: 84%

Slow dynamics under gravity: a nonlinear diffusion model

Arenzon

Levin

Sellitto

2003

Physica A: Statistical Mechanics and its Applications

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“…Following Refs. [21,26] we quantify the tap intensity by the parameter Γ = √ A − 1. For each value of Γ studied, 10 3 taps are carried out for equilibration followed by 5 × 10 3 taps for production.…”

Section: Initial Packingsmentioning

confidence: 99%

The effect of the packing fraction on the jamming of granular flow through small apertures

Uñac¹,

Vidales²,

Pugnaloni³

2012

J. Stat. Mech.

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Abstract. We investigate the flow and jamming through small apertures of a column of granular disks via a pseudo-dynamic model. We focus on the effect that the preparation of the granular assembly has on the size of the avalanches obtained. Ensembles of packings with different mean packing fractions are created by tapping the system at different intensities. Surprisingly, packing fraction is not a good indicator of the ability of the deposit to jam a given orifice. Different mean avalanche sizes are obtained for deposits with the same mean packing fraction that were prepared with very different tap intensities. It has been speculated that the number and size of arches in the bulk of the granular column should be correlated with the ability of the system to jam a small opening. We show that this correlation, if exists, is rather poor. A comparison between bulk arches and jamming arches (i.e., arches that block the opening) reveals that the aperture imposes a lower cut-off on the horizontal span of the arches which is greater than the actual size of the opening. This is related to the fact that blocking arches have to have the appropriate orientation to fit the gap between two piles of grains resting at each side of the aperture.

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“…Finally, our simulation results closely matches the experimental results. The experimental setup and the numerical simulation are described in detail in Refs [10,16].…”

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confidence: 99%

Effect of Rare Events on Out-of-Equilibrium Relaxation

et al. 2005

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This letter reports experimental and numerical results on particle dynamics in an out-ofequilibrium granular medium. We observed two distinct types of grain motion: the well known cage motion , during which a grain is always surrounded by the same neighbors, and low probability jumps, during which a grain moves significantly more relative to the others. These observations are similar to the results obtained for other out-of-equilibrium systems (glasses, colloidal systems, etc.). Although such jumps are extremely rare, by inhibiting them in numerical simulations we demonstrate that they play a significant role in the relaxation of out-of-equilibrium systems.PACS numbers: 45.70.-n,81.05 Glasses, colloids, and granular materials are characterized by structural disorder at the mesoscopic scale. These heterogeneous and metastable systems share a number of dynamical properties such as aging and slow relaxation, in which the cage motion of individual grains plays a significant role. Many experimental and numerical efforts have been made to observe and understand the out-of-equilibrium behavior exhibited by these systems [1,2,3,4,5,6,7,8]. A full understanding of the macroscopic behaviors of these systems requires detailed observations at the local scale (i.e. at the scale of a particle). The local dynamics in glasses is numerically simulated with Lennard-Jones liquids and the motion of atoms can be correlated to the α and β relaxation regimes [6]. Similar observations are obtained experimentally on colloidal systems using confocal microscopy [4], granular media in 2D [3], or 3D granular assemblies immersed in index matching fluid [7]. For all theses systems, the cage effect is clearly identified. Here we present an extensive experimental and numerical study of particle motion in 3D granular packing under gentle vertical tapping. Although this system is not thermal (its thermal energy is irrelevant in comparison with the energy needed to move a macroscopic grain), it is often presented as an ideal system to study out-of-equilibrium systems. From a microscopic point of view, this analogy is based on the idea that the geometry of the grains plays a major role, similar to geometrical frustration in thermal glasses. Indeed, like glasses, a granular assembly can be trapped in a metastable configuration unless an external perturbation such as shear or vibration is applied. Note that, unlike thermal energy, mechanical agitation of grains is, in general, neither stochastic nor isotropic. We expect, as others have found [2,3,7,9,10,11,12], that the results obtained are valid for any of the above mentioned out-of-equilibrium systems. Let us recall that when a dense granular sample is submitted to gentle external mechanical perturbations, its packing fraction Φ increases quickly at the beginning, then gradually approaches an asymptotic value. This slow compaction is similar to the slow dynamics observed in other out-of-equilibrium systems [2, 10, 13].The experimental results presented in the first part of this Letter are obtain...

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Numerical model for granular compaction under vertical tapping

Cited by 65 publications

References 28 publications

Slow dynamics under gravity: a nonlinear diffusion model

Slow dynamics under gravity: a nonlinear diffusion model

The effect of the packing fraction on the jamming of granular flow through small apertures

Effect of Rare Events on Out-of-Equilibrium Relaxation

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