Discrete simulation of dense flows of polyhedral grains down a rough inclined plane

Abstract

The influence of grain angularity on the properties of dense flows down a rough inclined plane are investigated. Three-dimensional numerical simulations using the nonsmooth contact dynamics method are carried out with both spherical (rounded) and polyhedral (angular) grain assemblies. Both sphere and polyhedra assemblies abide by the flow start and stop laws, although much higher tilt angle values are required to trigger polyhedral grain flow. In the dense permanent flow regime, both systems show similarities in the bulk of the material (away from the top free surface and the substrate), such as uniform values of the solid fraction, inertial number and coordination number, or linear dependency of the solid fraction and effective friction coefficient with the inertial number. However, discrepancies are also observed between spherical and polyhedral particle flows. A dead (or nearly arrested) zone appears in polyhedral grain flows close to the rough bottom surface, reflected by locally concave velocity profiles, locally larger coordination number and solid fraction values, smaller inertial number values. This dead zone disappears for smooth bottom surfaces. In addition, unlike sphere assemblies, polyhedral grain assemblies exhibit significant normal stress differences, which increase close to the substrate.

Effects of shape and size polydispersity on strength properties of granular materials

“…Hence, this method is numerically unconditionally stable and suited to the simulation of frictional contacts between particles. It has been extensively used for the simulation of granular materials [2][3][4]7,[10][11][12][13][25][26][27][28][29].…”

Nonlinear effects of particle shape angularity in sheared granular media

“…These shape characteristics strongly affect the rheology and texture of granular materials. This has been recently evidenced by a number of numerical and experimental studies carried out using angular particles [1][2][3][4][5][6][7][8][9][10][11][12] and by a number of investigations that have focused on other important characteristics such as elongation [13][14][15][16][17][18][19][20] or non-convexity [21,22]. The existing research results suggest that the effect of shape parameters is often nonlinear and counterintuitive as in the case of the unmonotonic relation between the elongation of the particles and the packing fraction [13,14,18].…”

Influence of the feeding mechanism on deposits of square particles

“…In the past few years, interest is growing in the study of the effect that particle shape has on the properties of both piles [12] and silos [13][14][15] as well as in other configurations [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. Among these works, some have focused on the role of faceted particles which have revealed conceptually new scenarios and special features.…”