A scalable OpenLB–LAMMPS framework for fully-resolved simulations of hindered settling of arbitrary non-spherical particles

Hindered settling of non spherical particles remains significantly less understood than spherical particles due to the computational challenges in resolving the complex contact mechanics and hydrodynamic interactions. In this paper, we present a scaleable fluid structure interaction (FSI) framework coupling the open-source LBM software in OpenLB (Krause et al., 2021) with the Discrete Element Method (DEM) implemented in LAMMPS (Thompson et al., 2022) to simulate arbitrary shaped rigid bodies in a fluid. Particle contacts are captured using a multi-sphere “clump” representation in DEM, while particle geometries are resolved on the fluid grid via voxelization. We validate our model against single and multi-particle benchmarks, and proceed to study the hindered settling of cubes in systems containing up to $O$(10$^5$) cubes. Our simulations show distinct differences between the settling of cubes and sphere, as cubes form pronounced coordination shells without face-parallel contact, in contrast to the contact-dominated clustering observed in spheres. Our calculations find that periodic boundary conditions might cause the velocity fluctuations along the direction of gravity to remain correlated for even the largest system size we studied. ... mehrThese findings highlight the role of particle morphology in suspension dynamics and demonstrate a robust framework for simulating large-scale geotechnical and particulate flows.