An LBM study on the local fluid flow in irregular monodisperse granular assemblies from DEM: Effects of particle shape

The estimation of permeability in granular materials such as sands is essential to various engineering applications. The permeability of granular assemblies is fundamentally influenced by their microstructures, especially for irregular particle assemblies. However, the links between such intrinsic morphological complexity of natural geo-materials and the hydraulic properties are still largely unexplored. This research bridges this gap with an advanced workflow that combines image processing, Lattice Boltzmann Method (LBM), and the non-spherical Discrete Element Method (DEM). The geometries of five natural sand particles with distinct shapes are extracted from micro-Computed Tomography images. Each of them is used to generate monodisperse assemblies with varied porosity, through a sphero-polyhedra-based DEM for irregular particles. Then, the pore fluid flow patterns inside the assemblies are unveiled using LBM. Results show that particle shape has a significant impact on fluid flow and velocity distribution and thus on permeability, tortuosity, and the hydraulic anisotropy.