In this work, self-assembly of periodic zigzag arrangement of monodisperse droplets through a flat microfluidic channel is numerically investigated. Our numerical technique is based on the boundary element method (BEM). It is found that droplets having zigzag arrangement tend to travel to channel centerline. We exhibit that non-deformable droplets do not drift normal to the channel centerline. While, as the capillary number increases, deformable droplets tend to approach more to the center of channel and their vertical velocity component increases. Our numerical results illustrate that droplets are dragged by a constant horizontal velocity component which is governed by the continuous phase flow rate. However, this situation is completely different for the vertical velocity component of droplets. We report how the vertical velocity component of droplet towards the channel centerline depends on control parameters such as droplet size, droplet distance, initial configuration, relative orientation of droplets, and capillary number. This dependency plays an important role in estimating necessary time to reach self-assembly.
Droplet migration Deformable droplets Solid particles Microfluidics Boundary element method
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Kadivar acknowledges the support of Shiraz University of Technology Research Council.
EK designed the research and developed the simulation code. MF and FG ran the simulations. EK analyzed and interpreted the results and wrote the manuscript.
Compliance with Ethical Standards
Conflict of interest
The authors declare that they have no conflicts of interest.
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