(469c) Dynamics of Three Elastic Capsules in Square Microfluidic Channels

The study of the interfacial dynamics of artificial or physiological capsules (i.e. membrane-enclosed fluid volumes) in Stokes flows has seen an increased interest during the last few decades due to their numerous engineering and biomedical applications. In addition, the study of the motion and deformation of capsules and biological cells in microfluidic channels is motivated by a wide range of applications including drug delivery, fabrication of microcapsules with desirable properties, cell sorting and characterization, micro-reactors with better mixing properties and of course its similarity to blood flow in vascular capillaries.

During the last years, these applications have motivated the investigation of the dynamics of a single elastic capsule in a variety of microfluidic channels, including cylindrical, square and rectangular channels, constrictions and expansions.

In the present talk, our interest is concentrated on the hydrodynamic interactions between three elastic capsules in a square microfluidic channel. In our computation investigation, we consider spherical capsules made of a strain-hardening membrane with comparable shearing and area-dilation resistance, while we study a wide range of capsule sizes and flow rates. Under these conditions, we have identified several merging formation patterns which depend on the capsule size and initial separation. The conditions for capsules separation and the effects of lubrication physics will also be presented. Our work provides useful physical insight on bioartificial capsules, cancerous cells and erythrocytes aggregation in the microcirculation.