Experimental investigation of vortex ring formation as a consequence of spiral vortex re-connection

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388998%3A_____%2F19%3A00571285" target="_blank" >RIV/61388998:_____/19:00571285 - isvavai.cz</a>

Result on the web

<a href="https://iopscience.iop.org/article/10.1088/1755-1315/405/1/012033/pdf" target="_blank" >https://iopscience.iop.org/article/10.1088/1755-1315/405/1/012033/pdf</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/1755-1315/405/1/012033" target="_blank" >10.1088/1755-1315/405/1/012033</a>

Result language

angličtina

Original language name

Experimental investigation of vortex ring formation as a consequence of spiral vortex re-connection

Original language description

The unsteady shape variation of a cavitating spiral vortex is experimentally studied pointing out the repetitive creation of vortex ring (or vortex loop). To generate the spiral vortex structure, a newly designed vortex generator is employed. This generator is used to study the decelerated swirling flow leading to the spiral vortex formation as a consequence of spiral vortex breakdown, which is considered to be the main triggering mechanism for the occurrence of the coherent vortex rope structure in the Francis turbine draft tube operated at part load conditions. Thanks to its design, the vortex generator enables to change the ratio between fluxes of axial momentum and tangential moment of momentum of generated swirl. Using this set-up, the behavior of the vortex structure changes in a similar way as the flow rate variation in the draft tube of Francis turbine. At certain flow conditions, the spiral vortex movement is characterized by sudden spiral entanglement leading to disconnection of a vortex ring and followed by spiral reconnection. Thanks to the transparent diffuser of the swirl generator apparatus, both high-speed camera recording of the cavitating vortex and PIV measurements of velocity fields at cavitationfree conditions are employed. The main aim of this paper is to link the visual observation of the above described vortex dynamics with the velocity fields measured in one longitudinal and one cross-sectional planes.

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

20302 - Applied mechanics

Project

<a href="/en/project/GA17-01088S" target="_blank" >GA17-01088S: 3D Instability of a Shear Layer in Adverse Pressure Gradient</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2019

Confidentiality

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

Article name in the collection

IOP Conference Series: Earth and Environmental Science

ISBN

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ISSN

1755-1307

e-ISSN

—

Number of pages

6

Pages from-to

012033

Publisher name

Universite Stuttgart

Place of publication

Stuttgart

Event location

Stuttgart

Event date

Oct 9, 2019

Type of event by nationality

WRD - Celosvětová akce

UT code for WoS article

000562376700033