Flocking and mesoscale turbulence in three-dimensional active fluids

Prasad Perlekar

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arXiv · 2601.17674

Flocking and mesoscale turbulence in three-dimensional active fluids

Prasad Perlekar

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Abstract

We numerically study the three-dimensional turbulence in a minimal model of an active fluid--the Toner-Tu-Swift-Hohenburg equation. For small activity, we observe bacterial turbulence, while for large activity, we uncover hitherto unexplored regime of a turbulent flock where a global order coexists with turbulence. We present a simple closure model that predicts the turbulent flock and also qualitatively explains the transition to the bacterial turbulence regime via a transcritical bifurcation.

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Prasad Perlekar. 2026-01-25. Flocking and mesoscale turbulence in three-dimensional active fluids. https://arxiv.org/abs/2601.17674

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