Regensburg 2019 – wissenschaftliches Programm
DY 20.3: Vortrag
Dienstag, 2. April 2019, 14:30–14:45, H3
Self-organized large-scale order in active fluids — Martin James1,2, Dominik Suchla1,2, and •Michael Wilczek1 — 1Max-Planck-Institut für Dynamik and Selbstorganisation, Göttingen — 2Georg-August-Universität Göttingen
Active fluids, such as dense suspensions of bacteria or microtubules and molecular motors, display a fascinating range of dynamical states. Active stresses exerted by the individual agents, along with their hydrodynamic interactions, generically lead to the emergence of mesoscale vortex patterns reminiscent of two-dimensional turbulence. In this presentation, we discuss how ordered flows emerge in a minimal continuum model of active fluids. In particular, we focus on a novel type of turbulence-driven pattern formation: a self-organized, dynamic vortex crystal. Crucially, this state emerges from an extended disordered transient characterized by an upscale energy transfer. Exploring the transition from active turbulence to the vortex crystal state with a focus on the role of fluctuations and system size, we find surprising analogies to classical phase transitions. For example, we observe locally ordered crystal domains, which share similarities with magnetic domains in ferromagnetic materials, separated by turbulent boundaries. Our results therefore explore one route to self-organization in active flows.