Emerging Periodic Behaviour in three-dimensional Active Nematics

Unlike traditional fluids, “active fluids” spontaneously flow by means of their own internal energy. Although they occur in various shapes and forms, the most studied active fluids are typically two-dimensional and are commonly composed of nematic rod-like constituents, such as a bacterial colonies, shaken granular rods, or films of sub-cellular filament/motor-protein mixtures. However, recent experimental work has produced extensile three-dimensional active nematic systems using kinesin and microtubule bundles dispersed in a passive colloidal liquid crystal. In this talk, I will describe our recent simulations of three-dimensional active nematic flows in microfluidic channels. Through a hybrid lattice Boltzmann and finite difference numerical scheme, we explore the spontaneous active nematohydrodynamic flow states in confining three-dimensional channels. In particular, we show that varying both the channel’s aspect ratio along the third dimension and boundary conditions, the system can enter into highly ordered and periodical flow states. Through observations of correlation functions and by tracking three-dimensional defects, we analyse the periodicity of these ordered states as well as their subsequent collapse over long times.