A spatially resolved fluid-solid interaction model for dense granular packs/Soft-Sand.

This is a Preprint and has not been peer reviewed. This is version 4 of this Preprint.


Download Preprint


Paula Alejandra Gago, Ali Q. Raeini, Peter King


Fluid flow through dense granular packs or soft sands can be described as a Darcy s flow for low injection rates, as the friction between grain-grain and grain-walls dominate the solid system behaviour. For high injection rates, fluid forces can generate grain displacement forming flow channels or ``fractures, which in turn modify local properties within the system, such as permeability and stress distribution. Due to this kind of ``self organized behaviour, a spatially resolved model for these interactions is required to capture the dynamics of these systems. In this work, we present a resolved model based on the approach taken by the CFDEM open source project which uses LIGGGHTS -- a discrete elements method (DEM)-- to model the granular behaviour and OpenFoam finite volume library for computational fluid dynamics (CFD), to simulate the fluid behaviour. The capabilities provided by the DEM engine allows the properties of the solid phase, such as inter-grain cohesion and solid confinement stress to be controlled. In this work the original solver provided by the CFDEM project was modified so as to deal with dense granular packs more effectively. Advantages of the approach presented are that it does not require external ``scaling parameters to reproduce well known properties of porous materials and that it inherits the performance provided by the CFDEM project. The model is validated by reproducing the well-known properties of static porous materials, such as its permeability as a function of the system porosity, and by calculating the drag coefficient for a sphere resting inside a uniform flow. Finally, we present fracture patterns obtained when modelling water injection into a Hele-Shaw cell, filled with a dense granular pack, at a central inlet.




Earth Sciences, Engineering, Materials Science and Engineering, Physical Sciences and Mathematics


CFDEM project, Resolved CFD-DEM, Soft-Sand Fractures


Published: 2019-05-09 08:29

Older Versions

GNU Lesser General Public License (LGPL) 2.1

Add a Comment

You must log in to post a comment.


There are no comments or no comments have been made public for this article.