The Decay of Forced Turbulent Coflow of He II Past a Grid

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F14%3A10291143" target="_blank" >RIV/00216208:11320/14:10291143 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68378271:_____/14:00427356

Výsledek na webu

<a href="http://dx.doi.org/10.1007/s10909-013-0938-y" target="_blank" >http://dx.doi.org/10.1007/s10909-013-0938-y</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s10909-013-0938-y" target="_blank" >10.1007/s10909-013-0938-y</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The Decay of Forced Turbulent Coflow of He II Past a Grid

Popis výsledku v původním jazyce

We present an experimental study of the decay of He II turbulence created mechanically, by a bellows-induced flow past a stationary grid in a 7x7 mm(2) superfluid wind tunnel. The temporal decay L(t) originating from various steady-states of vortex linelength per unit volume, L (0), has been observed based on measurements of the attenuation of second-sound, in the temperature range 1.17 K < T < 1.95 K. Each presented decay curve is the average of up to 150 single decay events. We find that, independently of T and L (0), within seconds past the sudden stop of the drive, all the decay curves show a universal behavior lasting up to 200 s, of the form L(t)ae(t-t (0))(-3/2), where t (0) is the virtual origin time. From this decay process we deduce the effective kinematic viscosity of turbulent He II. We compare our results with the bench-mark Oregon towed grid experiments and, despite our turbulence being non-homogeneous, find strong similarities.

Název v anglickém jazyce

The Decay of Forced Turbulent Coflow of He II Past a Grid

Popis výsledku anglicky

We present an experimental study of the decay of He II turbulence created mechanically, by a bellows-induced flow past a stationary grid in a 7x7 mm(2) superfluid wind tunnel. The temporal decay L(t) originating from various steady-states of vortex linelength per unit volume, L (0), has been observed based on measurements of the attenuation of second-sound, in the temperature range 1.17 K < T < 1.95 K. Each presented decay curve is the average of up to 150 single decay events. We find that, independently of T and L (0), within seconds past the sudden stop of the drive, all the decay curves show a universal behavior lasting up to 200 s, of the form L(t)ae(t-t (0))(-3/2), where t (0) is the virtual origin time. From this decay process we deduce the effective kinematic viscosity of turbulent He II. We compare our results with the bench-mark Oregon towed grid experiments and, despite our turbulence being non-homogeneous, find strong similarities.

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/GAP203%2F11%2F0442" target="_blank" >GAP203/11/0442: Vizualizace proudění kapalného helia</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

Journal of Low Temperature Physics

ISSN

0022-2291

e-ISSN

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Svazek periodika

175

Číslo periodika v rámci svazku

1-2

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

7

Strana od-do

324-330

Kód UT WoS článku

000332486200043

EID výsledku v databázi Scopus

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