Study of drafting, kissing and tumbling process of two particles with different sizes and densities using immersed boundary method in a confined medium

摘要

This paper presents a study on the drafting, kissing, tumbling (DKT) phenomenon between two circular and impermeable interacting particles of different sizes and densities in a confined medium in 2D using Immersed Boundary (IB) method. There are two different cases considered in this study. The first case, Case 1, deals with the scenario when the trailing particle was larger in size than the leading particle and in the second case, it was the other way round (Case 2). In both cases, apart from the size difference, the particles were assumed to have different densities. The paper investigated the effect of diameter ratio, as well as the effect of density differential on the dynamics of the settling particles. The obtained results clearly indicated that the size and the density of particles play an important role in the dynamics of the two interacting particles. The results suggested when the larger particle in both the cases was chosen to have higher density than the smaller particles, irrespective of diameter ratio and density difference, the particles went through one complete cycle of DKT. On the other hand, when the larger particle, irrespective of its initial position- leading or trailing, was having less density than the smaller particles, the results obtained was specific to diameter ratio as well as density difference.