Analysis of interactions between elastic capsules in two-dimensional microchannel flow

Interactions of two elastic capsules in two-dimensional (2D) microchannel flow are studied in this paper numerically. The numerical simulation method combines the finite volume method for the fluid domain with the front tracking technique for capturing and tracking the capsule membrane. Initially circular capsule is considered in simulations, and it is modeled as liquid medium enclosed by a thin membrane, for which linear elastic properties are incorporated. The results of cases of two center-line capsules shows that, when the initial capsule distance is small, two capsules tend to push each other at the beginning of process, and when the initial capsule distance is large enough, the interaction is negligible. The results of cases of upstream off-center capsule and downstream center-line capsule show that, the effect of the center-line capsule on the off-center capsule reduces with the increase of distance between the off-center capsule and the centerline, while the effect of the off-center capsule on the center-line capsule is still remarkable.