Spontaneous flow states in active nematics: a unified picture

Abstract

Continuum hydrodynamic models of active liquid crystals have been used to describe dynamic self-organising systems such as bacterial swarms and cytoskeletal gels. A key prediction of such models is the existence of self-stabilising kink states that spontaneously generate fluid flow in quasi-one dimensional channels. Using simple stability arguments and numerical calculations we extend previous studies to give a complete characterisation of the phase space for both contractile and extensile particles (ie pullers and pushers) moving in a narrow channel as a function of their flow alignment properties and initial orientation. This gives a framework for unifying many of the results in the literature. We describe the response of the kink states to an imposed shear, and investigate how allowing the system to be polar modifies its dynamical behaviour.

6 pages, 6 figures; submitted to Europhysics Letters

References in corpus (6)

• Hydrodynamic attraction of swimming microorganisms by surfaces
• Steady-state hydrodynamic instabilities of active liquid crystals: Hybrid lattice Boltzmann simulations
• Diffusion and spatial correlations in suspensions of swimming particles
• Shearing active gels close to the isotropic-nematic transition
• Generic phase diagram of active polar films
• Rheology of Active Filament Solutions

Cited by in corpus (27)

• Active Turbulence
• Defect dynamics in active nematics
• Sheared active fluids: thickening, thinning and vanishing viscosity
• Insensitivity of active nematic dynamics to topological constraints
• Active nematic materials with substrate friction
• Vesicle shape transformations driven by confined active filaments
• Morphodynamics of Active Nematic Fluid Surfaces
• Helical Flow States in Active Nematics
• Anchoring-driven spontaneous rotations in active gel droplets
• Stability of the interface of an isotropic active fluid
• Coexistence of defect morphologies in three dimensional active nematics
• Nonlinear spontaneous flow instability in active nematics
• Active nematic gels as active relaxing solids
• Flow patterns and defect dynamics of active nematics under an electric field
• Self-propulsion of an active polar drop
• Elasticity tunes mechanical stress localization around active topological defects
• Vector Formalism for Active Nematics in Two Dimensions
• Simulations of Three-dimensional Nematic Guidance of Microswimmers
• Motility and self propulsion of active droplets
• Active viscoelastic nematics with partial degree of order
• Hydrodynamic stability and pattern formation in hexatic epithelial layers
• Spontaneous flow created by active topological defects
• Hydrodynamic bend instability of motile particles on a substrate
• Nematic order condensation and topological defects in inertial active nematics
• Active nematic flows confined in a two dimensional channel with hybrid alignment at the walls: a unified picture
• On the temperature of an active nematic
• Dynamical arrest in active nematic turbulence