Visualization of secondary flow in a corner of a channel

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F49777513%3A23210%2F19%3A43959511" target="_blank" >RIV/49777513:23210/19:43959511 - isvavai.cz</a>

Result on the web

<a href="https://aip.scitation.org/doi/abs/10.1063/1.5138615" target="_blank" >https://aip.scitation.org/doi/abs/10.1063/1.5138615</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1063/1.5138615" target="_blank" >10.1063/1.5138615</a>

Result language

angličtina

Original language name

Visualization of secondary flow in a corner of a channel

Original language description

We report observation of secondary flow in one corner of developing channel air flow. Length of the channel, i.e. length of boundary layer, is 400?mm, which is 3.2 times the channel cross-sectional size. Three components of velocity are measured by using a Stereo Particle Image Velocimetry (PIV) technique in the measurement area of size 24×22?mm, which is perpendicular to the direction of main flow in the channel. The Reynolds number based on the length of the channel ranged from 4·104 to 8·105 and has been controlled via imposed velocity. At low Reynolds number we observe a laminar corner vortex having at all velocities the same orientation. This symmetry breaking is probably caused by an imperfectness of the experimental device. At Reynolds number around 8·104 this vortex starts to slightly variate its strength and position causing transition of boundary layers into turbulence at Re = 1.1·105. At higher Re this laminar vortex disappears from the instantaneous velocity fields, but it is still apparent in the averaged ones. It gets smaller and another oppositely oriented vortex forms; note that the second vortex is not observed in the instantaneous velocity fields, only in the ensemble average. At even higher Re, this secondary flow structure is smaller than the turbulent boundary layers, but its shape of a pair of counter-rotating vortices is conserved probably being a seed for secondary flow between fully developed boundary layers reported in the literature for longer channels with fully developed flow.

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

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OECD FORD branch

10305 - Fluids and plasma physics (including surface physics)

Project

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Continuities

S - Specificky vyzkum na vysokych skolach

Publication year

2019

Confidentiality

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

Article name in the collection

AIP Conference Proceedings

ISBN

978-0-7354-1936-0

ISSN

0094-243X

e-ISSN

1551-7616

Number of pages

6

Pages from-to

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Publisher name

American Institute of Physics Inc.

Place of publication

Neuveden

Event location

Plzeň

Event date

Jun 11, 2019

Type of event by nationality

WRD - Celosvětová akce

UT code for WoS article

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