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DY: Fachverband Dynamik und Statistische Physik

DY 13: Poster - Glasses / Stat. Phys. Bio. / Networks (joint session DY/BP/CPP/SOE)

DY 13.38: Poster

Dienstag, 1. April 2014, 09:30–12:30, P1

Feedback control of non-equilibrium dynamics of a multi-layer system of confined colloidal particles in planar shear flow — •Sascha Gerloff, Tarlan A. Vezirov, and Sabine H. L. Klapp — Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany

We perform computer simulations of charged colloidal particles in planar shear flow combined with feedback control. The particles interact via a combined Yukawa- and softsphere-potential. The system is known to form shear-induced multi-layer configurations in confinement and to show different intra-layer structures which depend on the applied shear rate [1]. The parameters are set to suit experimental data for ludox silica particles, which where previously studied [2,3].
We employ overdamped Brownian dynamics simulations to investigate the structure and the rheological behavior of the considered system. We then supplement our equations of motion by an additional dynamical equation, which corresponds to a feedback control mechanism for the shear rate via the shear stress. This enables the system to select between steady states dependent on the control parameters. Furthermore we present an approximation which estimates the transtion between steady states in the control parameter space analytically.
[1] T. A. Vezirov and S. H. L. Klapp, Phys. Rev. E 88, 5 (2013).
[2] S. Grandner and S. H. L. Klapp, J. Chem. Phys. 129, 244703 (2008).
[3] S. H. L. Klapp, Y. Zeng, D. Qu and R. v. Klitzing, Phys. Rev. Lett. 100, 118303 (2008).