Berlin 2018 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 21: Microswimmers (joint session BP/CPP/DY)
BP 21.6: Vortrag
Mittwoch, 14. März 2018, 16:30–16:45, H 1028
Phase diagram of a low Reynolds number swimmer near a wall — •Abdallah Daddi-Moussa-Ider1, Maciej Lisicki2,3, Christian Hoell1, and Hartmut Löwen1 — 1Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, Düsseldorf 40225, Germany — 2Department of Applied Mathematics and Theoretical Physics, Wilberforce Rd, Cambridge CB3 0WA, United Kingdom — 3Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
The hydrodynamic flow field generated by self-propelled active particles and swimming microorganisms is strongly altered by the presence of nearby boundaries in a viscous flow. Using a simple model swimmer composed of three-linked spheres, we show that the swimming trajectories near a non-slip wall reveal various interesting scenarios of motion depending on the initial orientation and the distance separating the swimmer from the wall. Accordingly, the swimmer can either be trapped by the wall, totally escape from the wall, or undergo an oscillatory gliding motion at a constant mean height above the wall. Using a far-field approximation, we find that the wall-induced correction at leading order has a quadrupolar flow structure where the translational and angular velocities of the swimmer decay as inverse third and fourth power with distance, respectively. The resulting equations of motion for the trajectories and the relevant order parameters fully characterize the transition between the phases and allow for an accurate description of the swimming behavior near a wall.