Influence of global rotation and Reynolds number on the large-scale features of a turbulent Taylor-Couette flow

TL;DR

This study investigates how global rotation and Reynolds number influence large-scale structures in turbulent Taylor-Couette flow, revealing the emergence of organized structures at specific rotation conditions through experimental analysis.

Contribution

It provides new experimental insights into the effects of rotation and Reynolds number on large-scale flow features and transitions in turbulent Taylor-Couette flow.

Findings

Large-scale structures emerge at specific rotation ratios.

Counterrotation leads to organized flow patterns.

Transition resembles a supercritical bifurcation.

Abstract

We experimentally study the turbulent flow between two coaxial and independently rotating cylinders. We determined the scaling of the torque with Reynolds numbers at various angular velocity ratios (Rotation numbers), and the behaviour of the wall shear stress when varying the Rotation number at high Reynolds numbers. We compare the curves with PIV analysis of the mean flow and show the peculiar role of perfect counterrotation for the emergence of organised large scale structures in the mean part of this very turbulent flow that appear in a smooth and continuous way: the transition resembles a supercritical bifurcation of the secondary mean flow.