Deformation and trajectory analysis of a pair of elastic particles under imposed flow

We carried out deformation and trajectory analysis of a pair of elastic particles under axisymmetric compressional and simple shear flows. The deformation dynamics of pair elastic particles are carried out initially for head-on interactions. We identified four stages during the deformation of particles: initial undeformed spherical particles, particles with flattened surfaces, the dimpled particles, and particles with fully established rims. The dynamics of the deformation of pair elastic particles is found to be fundamentally different from that of droplets, capsules, and vesicles systems under identical conditions. The effect of particle deformability on the pair trajectories (corresponds to offset interactions) of elastic particles is also studied. During these interactions, a huge negative pressure builds up before the test particle departs the reference particle, which allows its faster and asymmetric release. The trajectories exhibit significant deviation from the path followed by two rigid particles under identical conditions. Particularly under shear flow, this leads to spiraling out trajectories for both in-plane and off-plane interactions apart from the open trajectories.