Recurrent bursts via linear processes in turbulent environments

TL;DR

This paper demonstrates that recurrent bursts in turbulent flows can be modeled and predicted using a linear instability framework, providing insights into large-scale instabilities amidst small-scale turbulence.

Contribution

It introduces a simple linear instability model that accurately predicts the structure and timing of recurrent turbulence bursts in rotating Poiseuille flow.

Findings

Linear instability model predicts burst structure.

Model accurately captures burst time scales.

Flow exhibits nearly-periodic, self-sustained bursts.

Abstract

Large-scale instabilities occurring in the presence of small-scale turbulent fluctuations are frequently observed in geophysical or astrophysical contexts but are difficult to reproduce in the laboratory. Using extensive numerical simulations, we report here on intense recurrent bursts of turbulence in plane Poiseuille flow rotating about a spanwise axis. A simple model based on the linear instability of the mean flow can predict the structure and time scale of the nearly-periodic and self-sustained burst cycles. Rotating Poiseuille flow is suggested as a prototype for future studies of low-dimensional dynamics embedded in strongly turbulent environments.