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Lookup NU author(s): Dr Thomas Billam
This is the final published version of an article that has been published in its final definitive form by American Physical Society, 2017.
For re-use rights please refer to the publisher's terms and conditions.
© 2017 American Physical Society. We report evidence for an enstrophy cascade in large-scale point-vortex simulations of decaying two-dimensional quantum turbulence. Devising a method to generate quantum vortex configurations with kinetic energy narrowly localized near a single length scale, the dynamics are found to be well characterized by a superfluid Reynolds number Res that depends only on the number of vortices and the initial kinetic energy scale. Under free evolution the vortices exhibit features of a classical enstrophy cascade, including a k-3 power-law kinetic energy spectrum, and constant enstrophy flux associated with inertial transport to small scales. Clear signatures of the cascade emerge for N500 vortices. Simulating up to very large Reynolds numbers (N=32 768 vortices), additional features of the classical theory are observed: the Kraichnan-Batchelor constant is found to converge to C′≈1.6, and the width of the k-3 range scales as Res1/2.
Author(s): Reeves MT, Billam TP, Yu X, Bradley AS
Publication type: Article
Publication status: Published
Journal: Physical Review Letters
Print publication date: 01/11/2017
Online publication date: 31/10/2017
Acceptance date: 02/04/2016
Date deposited: 15/11/2017
ISSN (print): 0031-9007
ISSN (electronic): 1079-7114
Publisher: American Physical Society
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