Effect of periodic bottom plate heating on large scale flow in turbulent Rayleigh-Bénard convection

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378271%3A_____%2F15%3A00455210" target="_blank" >RIV/68378271:_____/15:00455210 - isvavai.cz</a>

Výsledek na webu

—

DOI - Digital Object Identifier

—

Jazyk výsledku

angličtina

Název v původním jazyce

Effect of periodic bottom plate heating on large scale flow in turbulent Rayleigh-Bénard convection

Popis výsledku v původním jazyce

We report analysis of temperature fluctuations measured inside a Rayleigh-Bénard convection cell of aspect ratio unity with steady and time-varying heating of the bottom boundary. The working fluid is cryogenic helium gas at Rayleigh number Ra = 1013, for which a large scale coherent flow (mean wind) exists. We observe the wind to occasionally vanish under both steady and time-varying heating conditions. However, with applied periodic modulation of the lower boundary temperature at the frequency of thewind, we can observe destruction of the periodic temperature variation at the cell mid-plane, due to relative changes in phase between the mean wind and the propagating temperature wave. The wind speed is not observed to change with modulation, demonstrating that it is set by mean properties of the system. Finally we propose that the frequency of the mean wind ? and hence the large scale Reynolds number ? could be better resolved by finding resonance with applied forcing.

Název v anglickém jazyce

Effect of periodic bottom plate heating on large scale flow in turbulent Rayleigh-Bénard convection

Popis výsledku anglicky

We report analysis of temperature fluctuations measured inside a Rayleigh-Bénard convection cell of aspect ratio unity with steady and time-varying heating of the bottom boundary. The working fluid is cryogenic helium gas at Rayleigh number Ra = 1013, for which a large scale coherent flow (mean wind) exists. We observe the wind to occasionally vanish under both steady and time-varying heating conditions. However, with applied periodic modulation of the lower boundary temperature at the frequency of thewind, we can observe destruction of the periodic temperature variation at the cell mid-plane, due to relative changes in phase between the mean wind and the propagating temperature wave. The wind speed is not observed to change with modulation, demonstrating that it is set by mean properties of the system. Finally we propose that the frequency of the mean wind ? and hence the large scale Reynolds number ? could be better resolved by finding resonance with applied forcing.

Druh

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

CEP obor

BM - Fyzika pevných látek a magnetismus

OECD FORD obor

—

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2015

Kód důvěrnosti údajů

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

Název periodika

Journal of Applied Fluid Mechanics

ISSN

1735-3572

e-ISSN

—

Svazek periodika

8

Číslo periodika v rámci svazku

3

Stát vydavatele periodika

IR - Íránská islámská republika

Počet stran výsledku

7

Strana od-do

483-489

Kód UT WoS článku

000362242800014

EID výsledku v databázi Scopus

2-s2.0-84929414967