Dresden 2017 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 6: Focus: Soft Particles in Flows I (joint focus session CPP/DY)
CPP 6.9: Vortrag
Montag, 20. März 2017, 13:00–13:15, ZEU 160
Migration reversal of soft particles in flows through wavy microchannels — •Matthias Laumann1, Alexander Farutin2, Chaouqi Misbah2, Diego Kienle1, and Walter Zimmermann1 — 1Theoretische Physik I, Universität Bayreuth, 95440 Bayreuth, Germany — 2Laboratoire Interdisciplinaire de Physique, CNRS Universite Alpes, UMR 5588, BP 87, F-28402 Saint-Martin, d’Heres Cedex, FranceH
We study soft particles in low Reynolds number flows through microchannels with wavy boundaries. In low Reynolds number flows through microchannels with straight boundaries, soft particles often tend via cross-streamline migration to the channel center (see e.g. [1]). We show, that for wavy channel boundaries this centric motion may be reversed once the modulation amplitude exceeds a (parameter dependent) threshold, in which case the soft particles migrate to off-center trajectories. This is shown by semi-analytical and numerical results for flexible dumbbells, models for ring polymers and capsules in microflows. The distance between off-center trajectories and the center of the microchannel depends on the particle’s elasticity and flow velocity as well as on the wavelength and the amplitude of the boundary modulation. Moreover, by increasing the flow velocity the migration direction may be reversed from out- to inward. Our insights can be exploited for particle separation with different properties in microchannels.
[1] B. Kaoui, G. H. Ristow, I. Cantat, C. Misbah, W. Zimmermann, Phys. Rev. E 77, 021903 (2008).