Normal fluid eddies in the thermal counterflow past a cylinder

TL;DR

This paper explains the stationary normal fluid eddies observed in superfluid helium counterflow around a cylinder using classical fluid dynamics principles, suggesting a novel link to vortex tangle polarization.

Contribution

It offers a classical fluid dynamics explanation for superfluid eddies and explores their connection to vortex tangle polarization, a novel insight in superfluid flow behavior.

Findings

Normal fluid eddies can be explained by classical fluid dynamics.

Eddies are stationary both upstream and downstream of the cylinder.

Potential link between eddy formation and vortex tangle polarization.

Abstract

A recent Particle Image Velocimetry (PIV) experiment in He II counterflow around a cylindrical obstacle showed the existence of apparently stationary normal fluid ddies both downstream (at the rear) and upstream (in front) of the cylinder. This rather surprising result does not have an analogue in experimental observations of classical fluid flows. We suggest that the explanation for the apparent stability of such eddies can be provided entirely from the viewpoint of classical fluid dynamics. We also discuss a possible connection between the emergence of the normal fluid eddies and the polarization of the vortex tangle in superfluid.