Flows in 3D active nematic systems

In the well studied 2D active nematic systems there is a well known correlation between the statistical properties of the topological structures and the flow structures in the system, given by the defect densities and vortex statistics. These properties are controlled by the intrinsic active length scale that is proportional to the nematic elasticity and inverse of the activity. In 3D systems, the system size becomes important and the observed phenomenology of the flow is determined by the system size that enters due to viscosity and the active length scale that is set by the nematic properties. In this talk, I will illustrate this fact in the context of the linearized hydrodynamic equations and numerical solutions of the full hydrodynamic theory in channel geometries.