Coupled Model And Numerical Simulation Of Sedimentation Circular Particles In The Viscous Flows Based On LBM-IBM-DEM

Sedimentation of particles in viscous fluid can be found in many nature andengineering applications, the understanding of the fundamental physical mechanismunderlying in these systems are highly demanded. For example, the start-up andsedimentation of the particles in the viscous flows are great influence upon thesediment deposition and flushing in estuarine and coastal engineering. And it ismore important for the corrosion of piers and piles to study the properties of theflow field. A lot of research results are given, but there is less work about the particle-fluid coupling mechanism. The intricate complexity of the coupled phenomenon dueto the particles’disorder movement is the main reason. The adoption of numericalsimulation can assist people in making decisions on trial conditions. Comparingwith the actual experiments, it is a cheaper and more convenient option. At present,numerical modelling has been a powerful tool in developing new or optimize existingengineering facilities.In this study, a coupled model has been established based on a combined Lat-tice Boltzmann Method (LBM)-Immersed Boundary Method (IBM)-DiscreteElement Method (DEM) scheme. The coupled model was used to analysis2D cir-cular particles sedimentation process in the incompressible Newtonian flows. Thehydrodynamic model of the incompressible viscous flow was based on the LBM. Amomentum exchange-based IBM was adopted to calculate the fluid-solid interac-tion force, the current coupled method combines the good features of the LBM andthe IBM by using two unrelated computational meshes. The Eulerian meshes areadopted to divide and compute the flow field; The Lagrangian meshes are adoptedto represent the moving particles. The kinematics and trajectory of the discrete par-ticles were evaluated by DEM, where the solid-solid interaction rules are based ontheoretical contact mechanics. Firstly, we tested two models of particle sedimenta-tion problem in a channel and compared the results with those reported in previousreferences. Finally, numerical simulations for2D circular particles sedimentation inincompressible viscous flows in cavity were carried out, the efect of the immersedtubes was disscused. The main contents and results are as follows:1. For the sedimentation question of2D circular particles in incompressible viscousflows, this paper established the coupled model which is based on LBM-IBM-DEM, and developed the software. 2. Using coupled model, this paper simulated diferent sedimentation process for2D circular particles in the incompressible viscous flows.