Molecular dynamics simulation of granular flows: Slip along rough inclined planes

Zheng, Xiaoming; Hill, James M.

doi:10.1007/s004660050349

Cited by 18 publications

(5 citation statements)

References 22 publications

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“…The behavior of granular matter contrasts with the one of classical fluid where a zero velocity condition is often achieved. Since there is no scale separation between the microscopic length scale (the grain) and the typical length of the flow, a change in the roughness of a boundary may dramatically modify the flow properties such as the slip velocity [68]. Which property is governed by a given boundary?…”

Section: Surface Rheologymentioning

confidence: 99%

Rheological properties of dense granular flows

Jop

2015

Comptes Rendus. Physique

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Section: Surface Rheologymentioning

confidence: 99%

Rheological properties of dense granular flows

Jop

2015

Comptes Rendus. Physique

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“…Recent studies, mostly addressing bulk behavior, tended to use rough boundary surfaces, both in experiments (as in [8][9][10]) and in simulations [3,5,[11][12][13], in order to induce deformation within the bulk material and study its rheology. Yet, in practical cases, such as hopper discharge flow [14], granular materials can be in contact with smooth walls (i.e., with asperities * Electronic address: zahra.shojaaee@uni-duisburg-essen.de much smaller than the particle diameter), in which case some slip (tangential velocity jump) is observed at the wall [15][16][17][18], and the velocity components parallel to the wall can vary very quickly over a few grain diameters. The specific behavior of the layer adjacent to the wall should then be suitably characterized in terms of a boundary zone constitutive law in order to be able to predict the velocity and stress fields.…”

Section: Introductionmentioning

confidence: 99%

Shear flow of dense granular materials near smooth walls. I. Shear localization and constitutive laws in the boundary region

et al. 2012

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We report on a numerical study of the shear flow of a simple two-dimensional model of a granular material under controlled normal stress between two parallel smooth, frictional walls, moving with opposite velocities ±V . Discrete simulations, which are carried out with the contact dynamics method in dense assemblies of disks, reveal that, unlike rough walls made of strands of particles, smooth ones can lead to shear strain localization in the boundary layer. Specifically, we observe, for decreasing V , first a fluid-like regime (A), in which the whole granular layer is sheared, with a homogeneous strain rate except near the walls; then (B) a symmetric velocity profile with a solid block in the middle and strain localized near the walls and finally (C) a state with broken symmetry in which the shear rate is confined to one boundary layer, while the bulk of the material moves together with the opposite wall. Both transitions are independent of system size and occur for specific values of V . Transient times are discussed. We show that the first transition, between regimes A and B, can be deduced from constitutive laws identified for the bulk material and the boundary layer, while the second one could be associated with an instability in the behavior of the boundary layer. The boundary zone constitutive law, however, is observed to depend on the state of the bulk material nearby.

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“…Other authors have focused on flows on rough chutes . Dippel and Wolf found in their study of molecular dynamic simulations of granular flow on a rough inclined plane in 2‐D that the coefficient of restitution has only a minor influence on the solid volume fraction as well as mean velocity of particles in the steady‐state flow of granular materials.…”

Section: Introductionmentioning

confidence: 99%

Simulation study of the effect of wall roughness on the dynamics of granular flows in rotating semicylindrical chutes

et al. 2015

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A discrete element model (DEM) is used to investigate the behavior of spherical particles flowing down a semicylindrical rotating chute. The DEM simulations are validated by comparing with particle tracking velocimetry results of spherical glass particles flowing through a smooth semicylindrical chute at different rotation rates of the chute. The DEM model predictions agree well with experimental results of surface velocity and particle bed height evolution. The validated DEM model is used to investigate the influence of chute roughness on the flow behavior of monodisperse granular particles in rotating chutes. To emulate different base roughnesses, a rough base is constructed out of a square close packing of fixed spherical particles with a diameter equal to, smaller, or larger than the flowing particles. Finally, the DEM model is used to study segregation in a binary density mixture for different degrees of roughness of the chute. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2117–2135, 2015

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Molecular dynamics simulation of granular flows: Slip along rough inclined planes

Cited by 18 publications

References 22 publications

Rheological properties of dense granular flows

Rheological properties of dense granular flows

Shear flow of dense granular materials near smooth walls. I. Shear localization and constitutive laws in the boundary region

Simulation study of the effect of wall roughness on the dynamics of granular flows in rotating semicylindrical chutes

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