Taylor rolls on tour: Slow drift of turbulent large-scale structures in flows with continuous symmetries

TL;DR

This paper investigates the slow, erratic drift of Taylor rolls in turbulent Taylor-Couette flow, revealing a phase transition to chaos and suggesting that such large-scale structure dynamics are common across wall-bounded turbulent flows.

Contribution

It provides the first detailed analysis of the slow drift of Taylor rolls in turbulent Taylor-Couette flow and compares these dynamics to other turbulent systems.

Findings

Discontinuous phase transition to spatio-temporal chaos with increasing system size.

Taylor rolls exhibit slow, erratic drift characterized by an effective diffusion coefficient.

The drift dynamics are similar to those observed in Rayleigh-Benard convection and Poiseuille flow.

Abstract

In Rayleigh-Benard convection and Taylor-Couette flow cellular patterns emerge at the onset of instability and persist as large-scale coherent structures in the turbulent regime. Their long-term dynamics has been thoroughly characterised and modelled for the case of turbulent convection, whereas turbulent Taylor rolls have received much less attention. Here we present direct numerical simulations of axisymmetric Taylor-Couette flow and show a discontinuous phase-transition to spatio-temporal chaos as the system size increases. Beyond this transition, Taylor rolls suddenly undergo erratic drifts evolving on a very slow time scale. We estimate an effective diffusion coefficient for the drift and compare the dynamics to analogous motions in Rayleigh-Benard convection and Poiseuille flow, suggesting that this spontaneous diffusive displacement of large coherent structures is common among different types of wall-bounded turbulent flows.