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SYAN: Symposium Active nematics: From 2D to 3D

SYAN 1: Active nematics: From 2D to 3D

SYAN 1.3: Invited Talk

Friday, October 1, 2021, 11:15–11:45, Audimax 1

Three-dimensional active nematic defects and their energetics — •Miha Ravnik — Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia — Josef Stefan Institute, Ljubljana, Slovenia

Active nematic fluids regularly exhibit topological defects, undergoing distinct dynamics which is determined by the coupling between the orientational order and the material flow. The type of defects and their role naturally depend on the dimensionality of the system, but importantly also on the geometry, confinement, flow, driving, and activity. Here, we present structures of topological defects in active nematic complex fluids, forming umbilic defects, singular loops, point defects, and disclinations. Specifically, we show defect profiles and dynamics in a three-dimensional active nematic droplet, also highlighting the role of different surface coupling regimes. Further, we demonstrate the dynamics of general singular defect loops in three-dimensional active nematics, which we show is strongly affected by the local twisting of the nematic director close to the singular defect cores. Finally, we discuss the energetics *energy dissipation and production- in active nematics as affected by topological defects.