Deformation of aggregates depositing on a plate in a viscous fluid simulated by a modified discrete element method

A three-dimensional modified discrete element method in which the hydrodyna mic drag force and static interparticle force are taken into account is pro posed to simulate the deformation process of two types of large aggregates depositing to a plate in a viscous fluid under Various external forces. It is found that the changes of the structure and the average cross-section de nsity of aggregates in the deformation process look reasonable, and the fol lowing microscopic features are predicted. (1) When the aggregate is not de stroyed completely by the external force, the portions of high density appe ar not only at the bottom but also at the position a little lower from the top. (2) When the aggregate is destroyed completely by the external force, the final aggregate is composed of at least two structures; the highly comp acted structure just above the plate and the much less compacted structure above it. (3) The density of an aggregate is able to be increased by applyi ng an external force weak enough for particles to rearrange themselves to f orm the compact structure. (4) The unevenness of the density distribution i n an aggregate of loose structure will be increased during the deformation, because each portion of different density in the aggregate will sediment a t a different velocity.