Berlin 2024 – scientific programme
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BP: Fachverband Biologische Physik
BP 35: Active Matter V (joint session BP/DY)
BP 35.11: Talk
Friday, March 22, 2024, 12:30–12:45, H 1028
Walking the Road to Active Nematic Turbulence — •Malcolm Hillebrand1,2 and Ricard Alert1,2 — 1Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzerstr 38, Dresden 01187 — 2Center for Systems Biology Dresden, Pfotenhauerstr 108, 01307 Dresden, Germany
Active matter, where internal energy consumption drives motion, exhibits a richly complex array of behaviours. In particular, the appearance of turbulent-like flows at very low Reynolds number, termed active turbulence, provides possibilities for chaotic fluid motion at scales as small as the surface of a cell. Here, in a hydrodynamic model of an active nematic, we thoroughly investigate the transition from smooth shear flow all the way to fully developed active turbulence. We utilise tools from dynamical systems theory, including Lyapunov exponents and time series analysis of velocity fields, as well as energy spectra and scaling laws, to describe the series of changes in dynamics that occur as we increase the activity. We find a sequence of increasingly unpredictable rearrangements between steady flow states that eventually give rise to continuously unstable chaos via a regime of apparent multistability. In addition, intermittent flow characteristics of fully active turbulent flows from simulations are compared to data from kinesin-microtubule experiments.
Keywords: Active turbulence; Living matter; Chaos; Fluid dynamics