Experimental evidence of a phase transition in a closed turbulent flow

TL;DR

This paper provides experimental evidence of a phase transition in a closed turbulent flow, marked by a divergence in symmetry-breaking susceptibility and intermittent symmetry-breaking states at high Reynolds numbers.

Contribution

The study demonstrates the existence of a phase transition in a turbulent flow through experimental measurements of symmetry-breaking susceptibility.

Findings

Susceptibility diverges at Re ≈ 90,000

Intermittencies observed between symmetry-breaking states

Flow exhibits a phase transition at high Reynolds number

Abstract

We experimentally study the susceptibility to symmetry breaking of a closed turbulent von K\'{a}rm\'{a}n swirling flow from $Re = 150$ to $Re \simeq 10^{6}$. We report a divergence of this susceptibility at an intermediate Reynolds number $Re = Re_\chi \simeq 90\,000$ which gives experimental evidence that such a highly space and time fluctuating system can undergo a "phase transition". This transition is furthermore associated with a peak in the amplitude of fluctuations of the instantaneous flow symmetry corresponding to intermittencies between spontaneously symmetry breaking metastable states.