Published in Granular Matter
We investigate how force chains in a granular packing influence and change during a tunnel excavation process. A two-dimensional (2D) frictional cohensionless packing is considered under gravity and a set of contiguous particles are removed in the interior. Using discrete element simulations on realistic non-spherical soil grains, we investigate th...
Published in Granular Matter
AbstractA new time-delayed periodic boundary condition (PBC) has been proposed for discrete element modelling (DEM) of periodic structures subject to moving loads such as railway track based on a box test which is normally used as an element testing model. The new proposed time-delayed PBC is approached by predicting forces acting on ghost particle...
Published in Granular Matter
AbstractThe spatial characteristics of wind-sand flow development are important for the morphological analysis of sand dunes (especially barchan dunes) used for curbing desertification projects. However, in previous studies, results were mostly obtained under the premise of a stable wind field. In this study, natural unsteady wind is accounted for,...
Published in Granular Matter
AbstractGeophysical granular flows occur at the surface of the Earth and other planets with reduced atmospheric pressure. In this paper, we investigate the run-out of dam-break flows of particle-air mixtures with fine (d=75μm\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackag...
Published in Granular Matter
Substantial research work has been focusing on the flow resistance of dense granular-fluid geophysical flows, e.g., debris flows. However, the mechanism of flow resistance as the dense debris flows transition to the dilute debris flow range (volumetric solid concentration 60% to 40%) remains an unsolved problem. Based on the accurate measurements o...
Published in Granular Matter
This paper numerically studies the densification mechanism of granular soil under dynamic compaction (DC) of proceeding impacts. Two-dimensional model of material system was established by the coupled discrete element-finite difference method to reveal the dynamic responses at both macro- and microscopic levels. Firstly, normalized crater deformati...
Published in Granular Matter
Extending the direct simulation Monte Carlo (DSMC) method to moderately dense granular flows has demanded recovering collisional pressures. There have been several reported DSMC variants that successfully recover the non-ideal equation of state but have largely been validated for systems with a homogeneous solids fraction field. Initially homogeneo...
Published in Granular Matter
Results from an experiment involving the measurement of individual particle stresses in a two-dimensional mono-disperse assembly of 579 ball bearings are presented. Using a combination of neutron radiography and strain scanning techniques, the full bi-axial stress state was obtained for each particle from which the full contact force network could ...
Published in Granular Matter
In this work we present results of the flow of monodisperse spheres in a two-dimensional silo. By taking high-speed video during the flow of grains, we are able to look at the microscopic dynamics of the individual grains. We report on how measures such as velocity fluctuations, non-affine motion, and dynamical heterogeneities change in as the syst...
Published in Granular Matter
Corona discharges are luminous signs of strong local electric fields allowing a continuous discharge into the surrounding atmosphere. They commonly occur at the ends of conductors at high voltage. Here we report the observation of a faint glow surrounding an insulating cm-sized box filled with mm-sized basalt beads. At an ambient pressure in the mb...
