Analog of Astrophysical Magnetorotational Instability in a Couette-Taylor Flow of Polymer Fluids

TL;DR

This paper reports the experimental observation of an 'elasto-rotational' instability in polymer fluid flow within a Couette-Taylor setup, serving as an analog to the astrophysical magnetorotational instability, under conditions where traditional instabilities are absent.

Contribution

The study introduces the first experimental demonstration of an instability in polymer fluids that mimics the magnetorotational instability in astrophysics, expanding understanding of flow instabilities in non-Newtonian fluids.

Findings

Observed 'elasto-rotational' instability in polymer flow

Demonstrated analogy to astrophysical magnetorotational instability

Identified conditions where classical instabilities are suppressed

Abstract

We report experimental observation of an instability in a Couette-Taylor flow of a polymer fluid in a thin gap between two coaxially rotating cylinders in a regime where their angular velocity decreases with the radius while the specific angular momentum increases with the radius. In the considered regime, neither the inertial Rayleigh instability nor the purely elastic instability are possible. We propose that the observed "elasto-rotational" instability is an analog of the magnetorotational instability which plays a fundamental role in astrophysical Keplerian accretion disks.