Abstract
We combine theory and numerical calculations to accurately predict the motion of anisotropic particles in shallow microfluidic channels, in which the particles are strongly confined in the vertical direction. We formulate an effective quasi-two-dimensional description of the Stokes flow around the particle via the Brinkman equation, which can be solved in a time that is two orders of magnitude faster than the three-dimensional problem. The computational speedup enables us to calculate the full trajectories of particles in the channel. To validate our scheme, we study the motion of dumbbell-shaped particles that are produced in a microfluidic channel using ‘continuous-flow lithography’. Contrary to what was reported in earlier work (Uspal et al. in Nat Commun 4:2666, 2013), we find that the reorientation time of a dumbbell particle in an external flow exhibits a minimum as a function of its disk size ratio. This finding is in excellent agreement with new experiments, thus confirming the predictive power of our scheme.
| Original language | English |
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| Article number | 77 |
| Number of pages | 12 |
| Journal | Microfluidics and Nanofluidics |
| Volume | 22 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - 1 Aug 2018 |
Funding
Acknowledgements This work is part of the D-ITP consortium, a program of the Netherlands Organisation for Scientific Research (NWO) that is funded by the Dutch Ministry of Education, Culture and Science (OCW). We acknowledge financial support from an NWO-VICI Grant. S. S acknowledges funding from the European Union’s Horizon 2020 programme under the Marie Skłodowska-Curie Grant agreement no. 656327. We thank A. Wijkamp of the van’t Hoff Laboratory for Physical and Colloid Chemistry for providing us with fluorescently labelled polystyrene beads, and S. O. Toscano for her help in acquiring experimental results.