Stratorotational instability in Taylor-Couette flow heated from above

TL;DR

This paper studies the stratorotational instability in Taylor-Couette flow with temperature stratification, revealing its nonlinear behavior and potential for laboratory experiments and astrophysical relevance.

Contribution

It demonstrates the nonlinear saturation of SRI in stratified Taylor-Couette flow and assesses angular momentum transport, bridging theoretical analysis with experimental feasibility.

Findings

SRI causes nonaxisymmetric flow patterns and outward angular momentum transport.

The viscosity coefficient α is of order unity in astrophysical scales.

Laboratory experiments with water and small temperature gradients are feasible.

Abstract

We investigate the instability and nonlinear saturation of temperature-stratified Taylor-Couette flows in a finite height cylindrical gap and calculate angular-momentum transport in the nonlinear regime. The model is based on an incompressible fluid in Boussinesq approximation with a positive axial temperature gradient applied. While both ingredients itself, the differential rotation as well as the stratification due to the temperature gradient, are stable, together the system becomes subject of the stratorotational instability and nonaxisymmetric flow pattern evolve. This flow configuration transports angular momentum outwards and will therefor be relevant for astrophysical applications. The belonging viscosity $\alpha$ coefficient is of the order of unity if the results are adapted to the size of an accretion disc. The strength of the stratification, the fluids Prandtl number and the boundary conditions applied in the simulations are well-suited too for a laboratory experiment using water and a small temperature gradient below five Kelvin. With such a rather easy realizable set-up the SRI and its angular momentum transport could be measured in an experiment.