Coupled Lbm/DEM Simulations with a Multi-Particle Partially Saturated Method- Theoretical and Computational Details

A coupled Discrete Element (DEM) - Lattice Boltzmann scheme was developed for modelling particle transports in fluid flows. The fluid particle interaction is modeled with the multi-particle partially saturated method (MPPSM). In the MPPSM, the fluid-solid collusion operator of the PSM scheme is split in two parts, where the solid operator is implemented as a boundary condition that properly enforces the rigid body motion in the particle interior. The original PSM scheme that is based on the cell concept, does not properly resolve the fluid flow in the vicinity of contacting particles. By introducing a solid collision operator and weight parameter B for each particle, the flow in the vicinity of contacting particles can be sufficiently resolved. An assessment of the scheme’s convergence rate and the effect of its parameters on performance is conducted. Finally, a necessary condition that allows the timestep factor (λ=Δt^LBM/Δt^DE) to attain values larger than one was found.