Dresden 2017 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 41: Active Matter II (joint session DY/BP/CPP)
DY 41.5: Vortrag
Donnerstag, 23. März 2017, 10:45–11:00, HÜL 186
Large scale vortex-patterns in dense suspensions of microswimmers — •Sebastian Heidenreich1, Jörn Dunkel2, Sabine H. L. Klapp3, and Markus Bär1 — 1Physikalisch-Technische Bundesanstalt — 2Massachusetts Institute of Technology — 3Technische Universität Berlin
In this talk we consider a prominent examples of an active biological fluid - dense suspension of swimming bacteria (e. g. Bacillus subtilis). For dense suspensions of bacterial swimmers, we have proposed a simple phenomenological model that predicts regular and turbulent vortex lattices and reproduces recent experimental findings of mesoscale turbulence in two- and three-dimensional suspensions of Bacillus subtilis in a quantitative manner [1]. A continuum model that couples the orientation of the swimmers with the surrounding velocity field was derived from stochastic equations of motions for individual active swimmers for a realistic hydrodynamical model of swimmers in a fluid [2]. This model contains the simple phenomenological model used in [1] as a special case. Furthermore, the continuum model enables us to understand the mechanism and properties of pattern formation in microswimmer suspensions and relate the physical parameters characterizing the individual swimmers and their interaction to the coefficients for continuum model equations.
[1] Dunkel, S. Heidenreich, K. Drescher, H. H. Wensink, M. Bär & R. E. Goldstein Phys. Rev. Lett. 110; New. J. Phys. (2013).
[2] S. Heidenreich, J. Dunkel, S. L. Klapp, and M. Bär (2016). Phys. Rev. E, 93