Particle‐resolved simulations of four‐way coupled, polydispersed, particle‐laden flows

Abstract

We present a collocated-grid framework for direct numerical simulations of polydisperse particles submerged in a viscous fluid. The fluid-particle forces are coupled with the immersed boundary method (IBM) while the particle-particle forces are modeled with a combination of contact and lubrication models, adapted for collocated grids. Our method is modified from the staggered-grid IBM of previous authors to a collocated-grid IBM by adapting the fluid and particle solvers. The method scales well on high-performance parallel computing platforms. It has been validated against various cases and is able to reproduce experimental results. Tuning parameters have been thoroughly calibrated to ensure the accuracy of the method. Finally, we demonstrate the capability of the method to simulate both monodispersed and bidispersed fluidized beds and reproduce the power law relationship between the inflow velocity and the porosity.

Investigating cohesive sediment dynamics in open waters via grain-resolved simulations

“…These Lagrangian markers are placed on the particle in equidistant spacing of the order of the grid cell size to discretize its surface. To couple the mesh of these Lagrangian markers to the fluid grid, a regularized Dirac delta function is introduced that spreads the forcing from the Lagrangian marker point on the particle surface to the Eulerian grid (Roma, Peskin, & Berger, 1999; Yao et al., 2022). Furthermore, is the desired velocity at the particle surface, is the interpolated fluid velocity computed prior to the forcing correction and is the volume element of the thin shell around particle that is associated with Lagrangian marker , and that is located inside a given fluid grid cell.…”