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Enstrophy Cascade in Decaying Two-Dimensional Quantum Turbulence

Lookup NU author(s): Dr Thomas BillamORCiD

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This is the final published version of an article that has been published in its final definitive form by American Physical Society, 2017.

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Abstract

© 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.

Publication metadata

Author(s): Reeves MT, Billam TP, Yu X, Bradley AS

Publication type: Article

Publication status: Published

Journal: Physical Review Letters

Year: 2017

Volume: 119

Issue: 18

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

URL: https://doi.org/10.1103/PhysRevLett.119.184502

DOI: 10.1103/PhysRevLett.119.184502

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