Stability and angular-momentum transport of fluid flows between corotating cylinders

TL;DR

This study uses direct numerical simulations to demonstrate that laboratory flows between corotating cylinders are hydrodynamically unstable and turbulent at low Reynolds numbers, with boundary conditions influencing global flow and angular-momentum transport.

Contribution

It reveals that axial boundary conditions induce instabilities leading to turbulence and enhanced angular-momentum transport in corotating cylinder flows.

Findings

Flows are hydrodynamically unstable and turbulent at low Reynolds numbers.

Instabilities originate from axial boundary conditions.

Flow instability enhances angular-momentum transport.

Abstract

Turbulent transport of angular momentum is a necessary process to explain accretion in astrophysical disks. Although the hydrodynamic stability of disk-like flows has been tested in experiments, results are contradictory and suggest either laminar or turbulent flow. Direct numerical simulations reported here show that currently investigated laboratory flows are hydrodynamically unstable and become turbulent at low Reynolds numbers. The underlying instabilities stem from the axial boundary conditions, affect the flow globally and enhance angular-momentum transport.