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DY: Fachverband Dynamik und Statistische Physik

DY 25: Posters - Soft Particles, Microswimmers, Microfluidics

DY 25.9: Poster

Dienstag, 21. März 2017, 18:15–21:00, P3

Active Swimmers and convection — •Jérémy Vachier, Stephan Herminghaus, and Marco G. Mazza — Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany

Active matter systems are driven out of thermodynamic equilibrium because the particles are able to convert energy into motion. Suspensions of self-propelled microscopic particles, such as swimming bacteria (E. Coli) or swimming algae (Chlamydomonas), exhibit collective motion. Describing the motion of these swimmers has an august place in the history of fluid mechanics. The small scale of our system implies that the hydrodynamics governing the motion are at low Reynolds numbers. We use the Stokes equation to describe the fluid, and we describe the swimmers as force dipoles, the swimmers are represented as spheroids, under Weeks-Chandler-Anderson (WCA) potential. We investigate the collective behaviour under mass convection due to a density mismatch. In order to simulate our system numerically, we use a hybrid method composed to Molecular Dynamics and Stochastic Rotation Dynamics. In this approach the fluid and the particles are represented with a particle based, coarse grained description. We study the dimensionless numbers, such as Péclet, Galilei and Sherwood numbers, characterizing the dynamics.