Dresden 2017 – scientific programme

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BP: Fachverband Biologische Physik

BP 41: Active Matter I (Joint Session DY/BP/CPP)

BP 41.8: Talk

Wednesday, March 22, 2017, 17:00–17:15, HÜL 186

Clustering of nematic active particles in low Reynolds number Navier-Stokes flow — •Rebekka Breier, Cristian C. Lalescu, Devin Waas, Michael Wilczek, and Marco G. Mazza — Max-Planck-Institut für Dynamik und Selbstorganisation, Göttingen

Large groups of self-propelled particles are ubiquitous in nature, from flocks of starlings and herds of wildebeests down to schools of fish and groups of bacteria or algae. Many of these creatures exist in (possibly mildly) turbulent habitats, like motile plankton in the pycnocline of the ocean. We study large systems of self-propelled, nematically aligning, hard core particles by means of molecular dynamic simulations which inhabit a turbulent environment. We investigate the active dynamics and compare the results from kinematic simulations (``synthetic turbulence'') with direct numerical simulations of the turbulent background field. We find a ``sweet spot'' for clustering, that is, an optimal strength of turbulence leads to very dense small-scale clusters. We explain the mechanism that induces clustering. Moreover, we investigate the effect of hard cores compared to point particles, and also give the appropriate dimensionless numbers to describe the dynamic transitions.