Coarse-grained pressure dynamics in superfluid turbulence

Jason Laurie*, Andrew W. Baggaley

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Quantum mechanics places significant restrictions on the hydrodynamics of superfluid flows. Despite this it has been observed that turbulence in superfluids can, in a statistical sense, share many
of the properties of its classical brethren; coherent bundles of superfluid vortices are often invoked
as an important feature leading to this quasi-classical behavior. A recent experimental study [E.
Rusaouen, B. Rousset, and P.-E. Roche, EPL, 118, 1, 14005, (2017)] inferred the presence of these
bundles through intermittency in the pressure field, however direct visualization of the quantized
vortices to corroborate this finding was not possible. In this work, we performed detailed numerical
simulations of superfluid turbulence at the level of individual quantized vortices through the vortex filament model. Through course-graining of the turbulent fields, we find compelling evidence
supporting these conclusions at low temperature. Moreover, elementary simulations of an isolated
bundle show that the number of vortices inside a bundle can be directly inferred from the magnitude of the pressure dip, with good theoretical agreement derived from the HVBK equations. Full
simulations of superfluid turbulence show strong spatial correlations between course-grained vorticity and low pressure regions, with intermittent vortex bundles appearing as deviations from the
underlying Maxwellian (vorticity) and Gaussian (pressure) distributions. Finally, simulations of a
decaying random tangle in an ultra-quantum regime show a unique fingerprint in the evolution of
the pressure distribution, which we argue can be fully understood using the HVBK framework.
Original languageEnglish
Article number014603
JournalPhysical Review Fluids
Volume5
DOIs
Publication statusPublished - 28 Jan 2020

Fingerprint

Superfluid
Turbulence
Vortex flow
Vortex
Bundle
Pressure Distribution
Vorticity
Pressure distribution
Vortex Filament
Tangles
Quantum theory
Intermittency
Spatial Correlation
Fingerprint
Quantum Mechanics
Gaussian distribution
Experimental Study
Hydrodynamics
Simulation
Visualization

Bibliographical note

©2020 American Physical Society

Cite this

Laurie, Jason ; Baggaley, Andrew W. / Coarse-grained pressure dynamics in superfluid turbulence. In: Physical Review Fluids. 2020 ; Vol. 5.
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Coarse-grained pressure dynamics in superfluid turbulence. / Laurie, Jason; Baggaley, Andrew W.

In: Physical Review Fluids, Vol. 5, 014603, 28.01.2020.

Research output: Contribution to journalArticle

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