Determining a representative element volume for DEM simulations of samples with non-circular particles

Particuology ◽  
2021 ◽  
Author(s):  
Peter Adesina ◽  
Catherine O’Sullivan ◽  
Tokio Morimoto ◽  
Masahide Otsubo
Keyword(s):  
Dem Simulations ◽  
Representative Element ◽  
Representative Element Volume

scholarly journals A methodology of re-generating a representative element volume of fractured rock mass

2020 ◽  
Vol 71 (4) ◽  
pp. 347-358
Author(s):  
DANG Hong-Lam ◽  
THINH Phi Hong
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Fracture Network ◽  
Hydraulic Calculation ◽  
Fractured Rock Mass ◽  
Fracture Characteristics ◽  
Mechanical Calculation ◽  
Representative Element ◽  
Representative Element Volume ◽  
Actual Fracture

In simulation of fractured rock mass such as mechanical calculation, hydraulic calculation or coupled hydro-mechanical calculation, the representative element volume of fractured rock mass in the simulating code is very important and give the success of simulation works. The difficulties of how to make a representative element volume are come from the numerous fractures distributed in different orientation, length, location of the actual fracture network. Based on study of fracture characteristics of some fractured sites in the world, the paper presented some main items concerning to the fracture properties. A methodology of re-generating a representative element volume of fractured rock mass by DEAL.II code was presented in this paper. Finally, some applications were introduced to highlight the performance as well as efficiency of this methodology.

Regularized lattice Bhatnagar–Gross–Krook model for the thermal flow in porous media

2017 ◽  
Vol 232 (3) ◽  
pp. 405-415 ◽  
Author(s):  
Zuo Wang ◽  
Jiazhong Zhang ◽  
Yan Liu ◽  
Le Wang
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Numerical Stability ◽  
Present Model ◽  
Flow In Porous Media ◽  
Thermal Flow ◽  
Representative Element ◽  
Flow And Heat Transfer ◽  
Representative Element Volume ◽  
Good Agreement

A regularized lattice Bhatnagar–Gross–Krook model for flow and heat transfer in porous media at the representative element volume scale is presented. In the model, the regularization process is extended to the existing Darcy–Forchheimer-based lattice Bhatnagar–Gross–Krook scheme. Numerical results show good agreement between the present model and the previous ones. Also, the present model shows better numerical stability than its lattice Bhatnagar–Gross–Krook counterpart.

Relationship between the representative element volume and discontinuity parameters

2020 ◽  
Vol 54 (1) ◽  
pp. qjegh2019-071
Author(s):  
Shengyuan Song ◽  
Qiang Xu ◽  
Jianping Chen ◽  
Fengyan Wang ◽  
Ying Liu ◽  
...  
Keyword(s):  
Fracture Network ◽  
Volume Density ◽  
Empirical Formulas ◽  
Representative Element ◽  
Linear Relationships ◽  
Discontinuity Orientation ◽  
Homogeneous Domains ◽  
Representative Element Volume ◽  
The Relationship ◽  
Dfn Model

We introduce an application of the discrete fracture network (DFN) model and 3D persistence to study the relationship between the representative element volume (REV) size and discontinuity information. To avoid the influence of heterogeneity on the distribution of discontinuities, the dam abutment rock mass of the Songta hydropower station is divided into eight statistically homogeneous domains based on the discontinuity orientation and trace length. An optimum DFN model is established for each homogeneous domain. Cubes of different sizes are extracted from the centre of the corresponding DFN model. Based on the discontinuity projection method, the 3D persistence values within the DFN model and each cube are calculated separately. The relative error of persistence for each cube and the DFN model are used to evaluate the size effect and to identify the REV size. Subsequently, the relationship between the determined REV size and the corresponding discontinuity information is systematically researched. Our results show that the discontinuity diameter, the volume density and the Fisher constant have separate linear relationships with the REV size. We present the empirical formulas for estimating the REV size according to the discontinuity diameter, the volume density and the Fisher constant.

scholarly journals MFIX-Exa: A path toward exascale CFD-DEM simulations

2021 ◽  
pp. 109434202110092
Author(s):  
Jordan Musser ◽  
Ann S Almgren ◽  
William D Fullmer ◽  
Oscar Antepara ◽  
John B Bell ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Element Model ◽  
Discrete Element Model ◽  
Software Framework ◽  
Chemical Reactors ◽  
Software Infrastructure ◽  
Fundamental Physics ◽  
Dem Simulations ◽  
Algorithmic Approaches

MFIX-Exa is a computational fluid dynamics–discrete element model (CFD-DEM) code designed to run efficiently on current and next-generation supercomputing architectures. MFIX-Exa combines the CFD-DEM expertise embodied in the MFIX code—which was developed at NETL and is used widely in academia and industry—with the modern software framework, AMReX, developed at LBNL. The fundamental physics models follow those of the original MFIX, but the combination of new algorithmic approaches and a new software infrastructure will enable MFIX-Exa to leverage future exascale machines to optimize the modeling and design of multiphase chemical reactors.

scholarly journals Simple Design Solution for Harsh Operating Conditions: Redesign of Conveyor Transfer Station with Reverse Engineering and DEM Simulations

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4008
Author(s):  
Błażej Doroszuk ◽  
Robert Król ◽  
Jarosław Wajs
Keyword(s):  
Reverse Engineering ◽  
Laser Scanning ◽  
Design For Manufacturing ◽  
Operating Conditions ◽  
Design Solution ◽  
Dem Simulations ◽  
Transfer Station ◽  
Transfer Stations ◽  
Dem Model ◽  
Current Operating

This paper addresses the problem of conveyor transfer station design in harsh operating conditions, aiming to identify and eliminate a failure phenomenon which interrupts aggregate supply. The analyzed transfer station is located in a Polish granite quarry. The study employs laser scanning and reverse engineering methods to map the existing transfer station and its geometry. Next, a discrete element method (DEM) model of granite aggregate has been created and used for simulating current operating conditions. The arch formation has been identified as the main reason for breakdowns. Alternative design solutions for transfer stations were tested in DEM simulations. The most uncomplicated design for manufacturing incorporated an impact plate, and a straight chute has been selected as the best solution. The study also involved identifying areas of the new station most exposed to wear phenomena. A new transfer point was implemented in the quarry and resolved the problem of blockages.

scholarly journals Comparative 3D DEM simulations of sand–structure interfaces with similarly shaped clumps versus spheres with contact moments

2021 ◽  
Author(s):  
A. Grabowski ◽  
M. Nitka ◽  
J. Tejchman
Keyword(s):  
Particle Shape ◽  
Friction Angle ◽  
Rigid Wall ◽  
Numerical Results ◽  
Contact Forces ◽  
Interface Roughness ◽  
Interface Shear ◽  
Dem Simulations ◽  
Micropolar Continua ◽  
Interface Behaviour

AbstractThree-dimensional simulations of a monotonic quasi-static interface behaviour between initially dense cohesionless sand and a rigid wall of different roughness during tests in a parallelly guided direct shear test under constant normal stress are presented. Numerical modelling was carried out by the discrete element method (DEM) using clumps in the form of convex non-symmetric irregularly shaped grains. The clumps had an aspect ratio of 1.5. A regular grid of triangular grooves (asperities) along the wall with a different height at the same distance was assumed. The numerical results with clumps were directly compared under the same conditions with our earlier DEM simulations using pure spheres with contact moments with respect to the peak and residual interface friction angle, width of the interface shear zone, ratio between grain slips and grain rotations, distribution of contact forces and stresses. The difference between the behaviour of clumps and pure spheres with contact moments proved to be noticeable in the post-peak regime due to a different particle shape. The rolling resistance model with pure spheres was proved to be limited for capturing particle shape effects. Three different boundary conditions along the interface were proposed for micropolar continua, considering grain rotations and grain slips, wall grain moments and wall grain forces, and normalized interface roughness. The numerical results in this paper offer a better understanding of the interface behaviour of granular bodies in DEM and FEM simulations.

scholarly journals Coarse Graining for Large-scale DEM Simulations of Particle Flow – An Investigation on Contact and Cohesion Models

2015 ◽  
Vol 102 ◽  
pp. 1484-1490 ◽  
Author(s):  
Daniel Schiochet Nasato ◽  
Christoph Goniva ◽  
Stefan Pirker ◽  
Christoph Kloss
Keyword(s):  
Large Scale ◽  
Coarse Graining ◽  
Particle Flow ◽  
Dem Simulations
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