Regensburg 2016 – scientific programme

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BP: Fachverband Biologische Physik

BP 30: Microswimmers I (Joint Session with DY)

BP 30.3: Talk

Tuesday, March 8, 2016, 10:15–10:30, H47

Dynamical density functional theory of microswimmers — •Andreas M. Menzel, Arnab Saha, Christian Hoell, and Hartmut Löwen — Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany

Microswimmers are found in nature in the form of self-propelling microorganisms, or they can be realized artificially, e.g. as Janus particles propelling due to self-induced phoretic effects. To describe and predict the collective behavior of many such interacting microswimmers on the mesoscopic level, statistical approaches are necessary.

Along these lines, we here report on a newly established dynamical density functional theory (DDFT). This theory includes steric as well as hydrodynamic interactions between individual swimmers within dilute and moderately concentrated suspensions of microswimmers. Minimal model microswimmers are considered. They self-propel by setting the surrounding fluid into motion, which leads to additional hydrodynamic interactions. Both pusher and puller swimming mechanisms are taken into account.

Via numerical simulations, our DDFT is demonstrated to reproduce effects recently observed in agent-based simulations. In a spherical trapping potential, this includes the formation of density rings and the self-organization in a symmetry-breaking state that resembles a hydrodynamic fluid pump. An additional instability is predicted that destabilizes the pumping state.