Influence of Secondary Flow Corner Vortex to Boundary Layer in a Channel Flow

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388998%3A_____%2F19%3A00518647" target="_blank" >RIV/61388998:_____/19:00518647 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/49777513:23210/19:43956107

Výsledek na webu

<a href="http://dx.doi.org/10.1063/1.5114739" target="_blank" >http://dx.doi.org/10.1063/1.5114739</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1063/1.5114739" target="_blank" >10.1063/1.5114739</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Influence of Secondary Flow Corner Vortex to Boundary Layer in a Channel Flow

Popis výsledku v původním jazyce

Boundary layer in developing channel flow of air is experimentally studied by using the Stereo Particle Image Velocimetry (PIV) technique. The measurement is performed at fixed distance 400 mm from the channel inlet and the Reynolds number (based on the channel length, i.e. the distance from the boundary layer origin) is controlled via the imposed velocity. Re ranges from 8•104 to 8•105.The displacement boundary layer thickness δ* varies from 1.7 to 2.5 mm while the momentum one θ from 0.9 to 1.3 mm. It is found, that the critical Reynolds number of transition to turbulence of the boundary layer is lowered by the vicinity of the other perpendicular wall of the square channel, more accurately – it is accelerated by the larger-scale secondary flow, which results into turbulence at slightly lower Reynolds numbers. The laminar-turbulent transition is first apparent on the profiles of the turbulent kinetic energy, later on the velocity profiles. The mechanism might be probably such, that the turbulent flow structures generated in the secondary flow in the corner via Richardson energy transfer mechanism migrate into the laminar boundary layer. While the largescale structures cannot feed from the limited-size boundary layer, the smaller ones can strengthen there.

Název v anglickém jazyce

Influence of Secondary Flow Corner Vortex to Boundary Layer in a Channel Flow

Popis výsledku anglicky

Boundary layer in developing channel flow of air is experimentally studied by using the Stereo Particle Image Velocimetry (PIV) technique. The measurement is performed at fixed distance 400 mm from the channel inlet and the Reynolds number (based on the channel length, i.e. the distance from the boundary layer origin) is controlled via the imposed velocity. Re ranges from 8•104 to 8•105.The displacement boundary layer thickness δ* varies from 1.7 to 2.5 mm while the momentum one θ from 0.9 to 1.3 mm. It is found, that the critical Reynolds number of transition to turbulence of the boundary layer is lowered by the vicinity of the other perpendicular wall of the square channel, more accurately – it is accelerated by the larger-scale secondary flow, which results into turbulence at slightly lower Reynolds numbers. The laminar-turbulent transition is first apparent on the profiles of the turbulent kinetic energy, later on the velocity profiles. The mechanism might be probably such, that the turbulent flow structures generated in the secondary flow in the corner via Richardson energy transfer mechanism migrate into the laminar boundary layer. While the largescale structures cannot feed from the limited-size boundary layer, the smaller ones can strengthen there.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

20302 - Applied mechanics

Projekt

<a href="/cs/project/EF16_026%2F0008389" target="_blank" >EF16_026/0008389: Výzkumná spolupráce pro dosažení vyšší účinnosti a spolehlivosti lopatkových strojů</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2019

Kód důvěrnosti údajů

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

Název statě ve sborníku

AIP Conference Proceedings

ISBN

978-073541858-5

ISSN

0094-243X

e-ISSN

—

Počet stran výsledku

5

Strana od-do

030011

Název nakladatele

American Institute of Physics Inc.

Místo vydání

College Park

Místo konání akce

Liptovsky Mikulas

Datum konání akce

19. 6. 2019

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

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