Effective viscosity in quantum turbulence: A steady-state approach

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F14%3A10291271" target="_blank" >RIV/00216208:11320/14:10291271 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68378271:_____/14:00431574

Výsledek na webu

<a href="http://dx.doi.org/10.1209/0295-5075/106/24006" target="_blank" >http://dx.doi.org/10.1209/0295-5075/106/24006</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1209/0295-5075/106/24006" target="_blank" >10.1209/0295-5075/106/24006</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Effective viscosity in quantum turbulence: A steady-state approach

Popis výsledku v původním jazyce

The concept of "effective viscosity" v(eff) of superfluid helium, widely used to interpret decaying turbulence, is tested in the steady-state case. We deduce.eff from measurements of the vortex line density, L, in a grid flow. The scaling of L with velocity confirms the validity of the heuristic relation defining v(eff), epsilon =v(eff) (kappa L)(2), where epsilon is the energy dissipation rate and. the circulation quantum. Within 1.17-2.16K, v(eff) is consistent with that from decays, allowing for uncertainties in flow parameters. Numerical simulations of the two-fluid equations yield a second estimation of v(eff) within an order of magnitude with all experiments. Its temperature dependence, more pronounced in numerics than experiments, shows a crossover from a viscous-dominated to a mutual-friction-based dissipation as temperature decreases, supporting the idea that the effective viscosity of a quantum turbulent flow is an indicator of the dissipative mechanisms at play.

Název v anglickém jazyce

Effective viscosity in quantum turbulence: A steady-state approach

Popis výsledku anglicky

The concept of "effective viscosity" v(eff) of superfluid helium, widely used to interpret decaying turbulence, is tested in the steady-state case. We deduce.eff from measurements of the vortex line density, L, in a grid flow. The scaling of L with velocity confirms the validity of the heuristic relation defining v(eff), epsilon =v(eff) (kappa L)(2), where epsilon is the energy dissipation rate and. the circulation quantum. Within 1.17-2.16K, v(eff) is consistent with that from decays, allowing for uncertainties in flow parameters. Numerical simulations of the two-fluid equations yield a second estimation of v(eff) within an order of magnitude with all experiments. Its temperature dependence, more pronounced in numerics than experiments, shows a crossover from a viscous-dominated to a mutual-friction-based dissipation as temperature decreases, supporting the idea that the effective viscosity of a quantum turbulent flow is an indicator of the dissipative mechanisms at play.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

BK - Mechanika tekutin

OECD FORD obor

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Projekt

<a href="/cs/project/GA14-02005S" target="_blank" >GA14-02005S: Kryogenní helium jako pracovní látka pro studium klasické a kvantové turbulence</a><br>

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2014

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Europhysics Letters

ISSN

0295-5075

e-ISSN

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Svazek periodika

106

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

6

Strana od-do

1-6

Kód UT WoS článku

000336376100009

EID výsledku v databázi Scopus

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