2D periodic patterns and transition to turbulence in active nematics

Abstract

We explore and characterize the 2D stationary patterns emerging from the spontaneous flow instability of an active nematic fluid, solving numerically the dynamics for a minimal model that has been proposed as the paradigm of active turbulence. We find that such solutions exist in the range of activity parameter 150 < jZj < 1500. We also test numerically the long-wavelength instability of such states, showing that they are unstable to period-doubling perturbations for activity above 500, leading to apparently chaotic dynamics. This confirms a scenario of transition to turbulence that has been proposed in this system, and reinforces the idea that the proposed minimal model, which neglects ow alignment coupling and assumes absence of topological defects, does capture the universal features of active turbulence