1/f noise in turbulent flows

TL;DR

This paper experimentally demonstrates the presence of 1/f noise in various turbulent flows, linking it to the dynamics of coherent structures and their state transitions across different physical systems.

Contribution

It provides the first experimental evidence of 1/f noise in turbulent flows and connects it to the dynamics of coherent structures and state transitions.

Findings

1/f noise observed in three turbulent flow configurations

Transitions between a small number of states cause 1/f fluctuations

Power-law distribution of interevent durations influences the 1/f exponent

Abstract

We report the experimental observation of $1/f$ fluctuations in three different turbulent flow configurations: the large scale velocity driven by a two-dimensional turbulent flow, the magnetic field generated by a turbulent swirling flow of liquid sodium and the pressure fluctuations due to vorticity filaments in a swirling flow. For these three systems, $1/f$ noise is shown to result from the dynamics of coherent structures that display transitions between a small number of states. The interevent duration is distributed as a power-law. The exponent of this power-law and the nature of the dynamics (transition between symmetric states or asymmetric ones) select the exponent of the $1/f$ fluctuations.