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DY: Fachverband Dynamik und Statistische Physik
DY 32: Posters DY - Statistical Physics, Brownian Motion and Nonlinear Dynamics
DY 32.10: Poster
Tuesday, March 23, 2021, 16:30–19:00, DYp
Depinning of confined colloidal dispersions under oscillatory shear — •Marcel Hülsberg and Sabine H.L. Klapp — ITP, Technische Universität Berlin, Germany
Strongly confined colloidal dispersions under shear exhibit a variety of dynamical phenomena, including a depinning transition similar to single particles that are driven over a periodic substrate potential [1]. Here, we investigate the depinning behavior of these systems under pure oscillatory shearing with shear rate γ(t) = γ0 cos(ω t), as it is a common scenario in rheological experiments [2]. The colloid’s depinning behavior is assessed from a microscopic level based on particle trajectories, which are obtained from overdamped Brownian Dynamics simulations. The numerical approach is complemented by an analytic one based on a single-particle model in the limit of weak driving. We determine the frequency-dependent critical shear rate amplitude γ0, crit(ω), which marks the onset of the depinning transition. Furthermore, we identify the dominant system-intrinsic time scale that dictates the scaling behavior of γ0, crit with driving frequency ω. Finally, we discuss potential consequences of the depinning behavior on the system’s rheological properties [2].
[1] S. Gerloff and S.H.L. Klapp, Phys. Rev. E 94(6), 062605 (2016)
[2] J.M. Brader, et al., Phys. Rev. E 82(6), 061401 (2010)