Berlin 2018 – scientific programme
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BP: Fachverband Biologische Physik
BP 14: Microswimmers DY I (joint session DY/BP/CPP)
BP 14.6: Talk
Tuesday, March 13, 2018, 15:15–15:30, BH-N 243
The frequency-dependent behavior of microswimmers in oscillating shear flow — •Kevin Schröer1, Patrick Kurzeja2, and Lothar Brendel1 — 1Faculty of Physics and CeNIDE, University of Duisburg-Essen, 47048 Duisburg, Germany — 2Institue of Mechanics, Technical University Dortmund, 44227 Dortmund, Germany
One possibility to alter the macroscopic properties of a self-propelled nanoparticle suspension is the introduction of inhomogeneities in the propulsion mechanism, which leads to drastic changes in the collective behavior [1].
A new approach is presented for sheared suspensions: the control via oscillating walls. The oscillation frequency determines the thickness of a viscous boundary layer that surrounds the inertia-dominated center region. This is characterized by the Womersley number Wo, being the ratio between viscous and inertial forces [2]. As a result, regions of particle rotation and translation can be varied by this frequency.
Using this setup, we investigate the impact of Wo on the rheology of a dilute microswimmer suspension by means of Multi-Particle Collision Dynamics (MPC) simulations. This method is suited to capture hydrodynamics and thermal fluctuations and has been used in related topics like dilute suspensions in a gravity perturbed annular shear [3] or bidisperse segregation in a Hagen-Poiseuille flow [4].
[1] M. P. Magiera and L. Brendel, Phys. Rev. E 92, 1 (2015)
[2] P. Kurzeja et al., JASA 140, 4378 (2016)
[3] K. Schröer et al., EPJ Web of Conferences, 140 (2017)
[4] P. Kanehl and H. Stark, J. Chem. Phys. 142, 214901 (2015)