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BP: Fachverband Biologische Physik

BP 17: Microswimmers (joint DY/BP)

BP 17.10: Vortrag

Dienstag, 1. April 2014, 12:00–12:15, ZEU 146

Synchronization of rigid microrotors by time-dependent hydrodynamic interactions — •Mario Theers and Roland Winkler — Theoretical Soft Matter and Biophysics, Institute for Advanced Simulation and Institute of Complex Systems, Forschungszentrum Juelich, D-52425 Juelich, Germany

The synchronized beating of flagella is fundamental for the coordinated motion of microswimmers such as spermatozoa, bacteria, protozoa, or algae. It is a longstanding conjecture that this microscopic synchronization could be induced by hydrodynamic interactions. However, synchronization is not easily achieved for low Reynolds-number fluids, which are described by Stokes equations. The presence of kinematic reversibility combined with swimmer symmetries may prevent synchronization.

We provide an extension of previous low-Reynolds number studies by analyzing the linearized, time-dependent Navier-Stokes equations instead of the usually adopted Stokes equations. As a model system, we investigate the emergent dynamical behavior of hydrodynamically coupled microrotors and demonstrate that time-dependent hydrodynamic interactions inevitably lead to synchronization of their rotational motion, which is not achieved on the basis of Stokes equations. We show that the system can be described by coupled nonlinear integro-differential equations and derive analytical results for the the phase difference. Additionally, results are compared to mesoscale hydrodynamic simulations. Our studies provide a deeper insight into the nature of hydrodynamic interactions between microswimmers.