Dresden 2017 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 37: Aktive Matter I (joint session DY/BP/CPP)

DY 37.12: Talk

Wednesday, March 22, 2017, 18:00–18:15, HÜL 186

Rheology and shear-induced dynamics of passive and active anisotropic colloids — •Henning Reinken and Sabine H. L. Klapp — Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany

We investigate the rheology of passive and active fluids focusing on shear-induced instabilites and emerging spatiotemporal structures. Prominent examples of active matter, which is composed of self-driven units converting energy into motion on the microscopic scale, are anisotropic colloidal particles with polar or nematic interactions. Already in the passive case, these systems show very interesting rheological properties including oscillatory orientational states and shear banding [1]. Introducing activity into the system modifies the rheology and leads to additional instabilities [2].

We study the rheological properties via the Doi-Hess theory [1], a continuum theoretical approach. In this framework, the orientational order parameter is coupled to the flow via the stress tensor, which can be extended to include an active stress [2]. In particular, we focus on parameter regimes where interesting spatiotemporal structures like banded states or active turbulence [3] emerge and discuss the differences between active and passive systems.

[1] R. Lugo-Frías, H. Reinken, S. H. L. Klapp, Eur. Phys. J. E 39: 88 (2016).
[2] M. C. Marchetti et al. Rev. Mod. Phys. 85, 1143 (2013).
[3] S. Heidenreich, J. Dunkel, S. H. L. Klapp, M. Bär, Phys. Rev. E 94, 020601(R) (2016).