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Regimes of turbulence without an energy cascade

Lookup NU author(s): Professor Carlo Barenghi, Emeritus Professor Yuri Sergeev, Dr Andrew BaggaleyORCiD

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This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Abstract

Experiments and numerical simulations of turbulent 4He and 3He-B have established that, at hydrodynamic length scales larger than the average distance between quantum vortices, the energy spectrum obeys the same 5/3 Kolmogorov law which is observed in the homogeneous isotropic turbulence of ordinary fluids. The importance of the 5/3 law is that it points to the existence of a Richardson energy cascade from large eddies to small eddies. However, there is also evidence of quantum turbulent regimes without Kolmogorov scaling. This raises the important questions of why, in such regimes, the Kolmogorov spectrum fails to form, what is the physical nature of turbulence without energy cascade, and whether hydrodynamical models can account for the unusual behaviour of turbulent superfluid helium. In this work we describe simple physical mechanisms which prevent the formation of Kolmogorov scaling in the thermal counterflow, and analyze the conditions necessary for emergence of quasiclassical regime in quantum turbulence generated by injection of vortex rings at low temperatures. Our models justify the hydrodynamical description of quantum turbulence and shed light into an unexpected regime of vortex dynamics.


Publication metadata

Author(s): Barenghi CF, Sergeev YA, Baggaley AW

Publication type: Article

Publication status: Published

Journal: Scientific Reports

Year: 2016

Volume: 6

Online publication date: 20/10/2016

Acceptance date: 30/09/2016

Date deposited: 30/09/2016

ISSN (electronic): 2045-2322

Publisher: Nature Publishing Group

URL: http://dx.doi.org/10.1038/srep35701

DOI: 10.1038/srep35701


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Funding

Funder referenceFunder name
EP/I019413/1Engineering and Physical Sciences Research Council (United Kingdom)
EP/I019413/1EPSRC

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