Helical Flow States in Active Nematics

TL;DR

This paper demonstrates that confining active nematic fluids in 3D channels can produce two distinct, self-organized helical flow states with complex structures, driven by activity and boundary conditions.

Contribution

It reveals two novel helical flow states in active nematics confined in 3D channels, expanding understanding of symmetry-breaking and organization in active fluid systems.

Findings

Braided anti-parallel streams with double helix structure

Axially aligned counter-rotating vortices

Active nematics can form complex 3D flow patterns

Abstract

We show that confining extensile nematics in 3D channels leads to the emergence of two self-organized flow states with nonzero helicity. The first is a pair of braided anti-parallel streams - this double helix occurs when the activity is moderate, anchoring negligible and reduced temperature high. The second consists of axially aligned counter-rotating vortices - this grinder train arises between spontaneous axial streaming and the vortex lattice. These two unanticipated helical flow states illustrate the potential of active fluids to break symmetries and form complex but organized spatio-temporal structures in 3D fluidic devices.