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DY: Fachverband Dynamik und Statistische Physik
DY 58: Poster - Fluids
DY 58.10: Poster
Donnerstag, 19. März 2015, 16:00–18:00, Poster A
Lateral migration of soft microparticles in wavy microchannels — •Matthias Laumann1, Badr Kaoui1, Alexander Farutin2, Andreas König1, Diego Kienle1, Chaouqi Misbah2, and Walter Zimmermann1 — 1Theoretische Physik, Universität Bayreuth, Bayreuth — 2Laboratoire Interdisciplinaire de Physique, CNRS-Univerisite Joseph Fourier / UMR 5588, BP 87, F-28402 Saint-Martin d'Heres Cedex, France
We study the cross-streamling migration (CSM) of deformable particles in the limit of vanishing Reynold number in 2D and 3D Poiseuille channel flow, which boundaries are spatially modulated. Using 1D dumbbels, 2D ring polymers, and 3D tetrahedrons (all of which may be symmetric or asymmetric), we demonstrate how the CSM can be modified when the waviness of the micro-channel is varied. Starting with the case of flat boundaries (zero modulation), these particles perform a CSM that is always directed towards the channel center[1]. In the case of wavy boundaries, this centric motion may be reversed once the modulation amplitude exceeds a lower threshold, in which case the particles migrate off-center and approach a stationary, non-curvelinear trajectory, located between the walls and the center of the channel. The distance between such a trajectory and channel center can be increased by turning up the modulation amplitude, but depends also on other parameters such as the particle elasticity, for example. The results shown are obtained via a perturbation calculation of the wavy Poiseuille flow in the limit of small modulation amplitudes, and compared with those from Stokesean particle dynamics for arbitrary modulation amplitudes, showing good agreement. Out study suggests that the flow generated between wavy boundaries may be exploited for the separation of particles with varying properties in microfluidic channels.
[1]B. Kaoui, G. H. Ristow, I. Cantat, C. Misbah, W. Zimmermann, Phys. Rev. E 77, 021903 (2008)