Numerical study of the particle sedimentation in a viscous fluid using a coupled DEM-IB-CLBM approach

摘要

At low terminal Reynolds numbers Re = 2-10, there are multiple asymmetrical principal movement states for the sedimentation of a pair of particles in a channel filled with a viscous fluid. The main emphasis of this work is to investigate the formation process of these states and the effect of the natural rotation on the process when particles are released symmetrically. The flow field around each particle is fully resolved with an Immersed Boundary Method (IBM) coupled with the Cascaded Lattice Boltzmann Method (CLBM). An improved algorithm is developed to couple IBM with CLBM which can fully exploit the Graphics Processing Unit (GPU) for parallelisation. The collision between particles is handled with the Discrete Element Model (DEM). The approach is validated considering the sedimentation of a single particle released asymmetrically and also the Drafting-Kissing-Tumbling (DKr) problem of two particles.