Relaxation of superfluid vortex bundles via energy transfer to the normal fluid

Journal Article · Wed Aug 01 04:00:00 EDT 2007 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.76.054503· OSTI ID:21055108

Kivotides, Demosthenes ^[1]

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1. Center for Risk Studies and Safety, University of California, Santa Barbara, California 93117 (United States)

We apply numerical and computational analyses to the decay of a topologically nontrivial, bundle-structured superfluid vortex tangle via mutual friction effected energy transfer to an initially stationary, viscous normal fluid. We demonstrate that, as long as the coherent superfluid vorticity structures remain intact, the induced normal-fluid vorticity acquires a similar to the superfluid vorticity morphology, and the normal-fluid energy spectrum mimics the superfluid energy spectrum presenting a low-wavenumber scaling regime. After a (smaller than the integral advective time scale) transient, the superfluid vorticity bundles disintegrate; this is followed by the decay of normal-fluid energy. The kinetic energies of the two fluids are mismatched throughout the decay period, and the dismantling of coherent vorticity destroys the low-wavenumber energy spectrum scaling in both fluids. At the point of maximum normal-fluid energy, the circulation of the induced normal-fluid vortices is comparable to the ''macroscopic'' circulation of the superfluid vorticity bundles. We show that the superfluid dynamics are dominated throughout the decay period by inertial rather than mutual friction effects, that the formation of bundlelike coherent superfluid vortices cannot be the outcome of pure (reconnecting) Biot-Savart dynamics, and that superfluid vortex length dynamics are not analogous to superfluid energy dynamics. We conjecture that the dynamics of fully developed, turbulent thermal superfluid flow could be described in terms of interactions of cyclic coherent vorticity patterns in both fluids.

• OSTI ID: 21055108
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 5 Vol. 76; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DECAY
ENERGY SPECTRA
ENERGY TRANSFER
FLUIDS
FRICTION
KINETIC ENERGY
LENGTH
RELAXATION
SUPERFLUIDITY
VORTICES