Super Stability of Laminar Vortex Flow in Superfluid 3He-B

TL;DR

This study demonstrates that vortex flow in superfluid 3He-B remains laminar at high Reynolds numbers due to quantum effects, with turbulence only arising from significant perturbations or boundary interactions.

Contribution

It reveals the quantum origin of vortex stability in superfluid 3He-B and shows laminar flow persists at Reynolds numbers where turbulence occurs in other fluids.

Findings

Vortex flow remains laminar up to Re~1000 in 3He-B.

Surface pinning and vortex reconnections are suppressed in 3He-B.

Large perturbations induce turbulence in superfluid 3He-B.

Abstract

Vortex flow remains laminar up to large Reynolds numbers (Re~1000) in a cylinder filled with 3He-B. This is inferred from NMR measurements and numerical vortex filament calculations where we study the spin up and spin down responses of the superfluid component, after a sudden change in rotation velocity. In normal fluids and in superfluid 4He these responses are turbulent. In 3He-B the vortex core radius is much larger which reduces both surface pinning and vortex reconnections, the phenomena, which enhance vortex bending and the creation of turbulent tangles. Thus the origin for the greater stability of vortex flow in 3He-B is a quantum phenomenon. Only large flow perturbations are found to make the responses turbulent, such as the walls of a cubic container or the presence of invasive measuring probes inside the container.