Berlin 2012 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 22: Posters I

DY 22.19: Poster

Mittwoch, 28. März 2012, 17:00–19:00, Poster A

The Three-Body Model of a Micro-swimmer — •Jayant Pande¹, Kristina Pickl², Jan Götz², Klaus Iglberger³, Klaus Mecke¹, Ulrich Rüde^2,3, and Ana-Sunčana Smith¹ — ¹Institut für Theoretische Physik, Universität Erlangen-Nürnberg, Erlangen, Germany — ²Lehrstuhl für Systemsimulation, Universität Erlangen-Nürnberg, Erlangen, Germany — ³Zentralinstitut für Scientific Computing, Universität Erlangen-Nürnberg, Erlangen, Germany

Engineered micro-devices which are capable of moving alone through a fluid can be of crucial importance in various fields of science. The simplest model of such a micro-device has been introduced by Najafi and Golestanian, and consists of three spheres connected by two arms which move in a non time-reversible fashion. This geometry has been analyzed by Golestanian and Ajdari and by Felderhof, under the assumption that the deformations of the swimmer's arms and the forces driving them are known, respectively. We expand these two approaches by taking higher order terms into account, and find the regime of their agreement. For sinusoidal driving forces, we show that the movement of the arms is restricted by the geometrical parameters, which imposes an upper bound on the velocity. We also extend the three-sphere model by replacing some or all of the spheres in the swimmer by cylindrical capsules, thus introducing some inherent asymmetry to the swimmer design, thereby affecting the swimming efficiency. All analytical results are presented in conjunction with those from a simulation framework employing a rigid-body engine coupled to a Lattice-Boltzmann fluid solver.