Enstrophy Cascade in Decaying Two-Dimensional Quantum Turbulence

Reeves, Matthew T.; Billam, Thomas P.; Yu, Xiaoquan; Bradley, Ashton S.

Abstract

We report evidence for an enstrophy cascade in large-scale point-vortex simulations of decaying twodimensional 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 N ≳ 500 vortices. Simulating up to very large Reynolds numbers (N ¼ 32 768 vortices), additional features of the classical theory are observed: the KraichnanBatchelor constant is found to converge to C0 ≈ 1.6, and the width of the k−3 range scales as Re1=2 s .

Citation

Reeves, M. T., Billam, T. P., Yu, X., & Bradley, A. S. (2017). Enstrophy Cascade in Decaying Two-Dimensional Quantum Turbulence. Physical Review Letters, 119(18), Article 184502. https://doi.org/10.1103/physrevlett.119.184502

• Journal Article Type: Article
• Online Publication Date: Oct 31, 2017
• Publication Date: Oct 31, 2017
• Deposit Date: Nov 14, 2017
• Publicly Available Date: Nov 14, 2017
• Journal: Physical Review Letters
• Print ISSN: 0031-9007
• Electronic ISSN: 1079-7114
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 119
• Issue: 18
• Article Number: 184502
• DOI: https://doi.org/10.1103/physrevlett.119.184502
• Public URL: https://durham-repository.worktribe.com/output/1344161