Proper Orthogonal Decomposition of Self-Induced Instabilities in Decelerated Swirling Flows and Their Mitigation Through Axial Water Injection

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26210%2F17%3APU123685" target="_blank" >RIV/00216305:26210/17:PU123685 - isvavai.cz</a>

Result on the web

<a href="http://fluidsengineering.asmedigitalcollection.asme.org/article.aspx?articleid=2612926" target="_blank" >http://fluidsengineering.asmedigitalcollection.asme.org/article.aspx?articleid=2612926</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1115/1.4036244" target="_blank" >10.1115/1.4036244</a>

Result language

angličtina

Original language name

Proper Orthogonal Decomposition of Self-Induced Instabilities in Decelerated Swirling Flows and Their Mitigation Through Axial Water Injection

Original language description

The swirling flow exiting the runner of a hydraulic turbine is further decelerated in the discharge cone of the draft tube to convert the excess of dynamic pressure into static pressure. When the turbine is operated far from the best efficiency regime, particularly at part load, the decelerated swirling flow develops a self-induced instability with a precessing helical vortex and the associated severe pressure fluctuations. This phenomenon is investigated numerically in this paper, for a swirl apparatus configuration. The unsteady three-dimensional (3D) flow field is analyzed using a proper orthogonal decomposition (POD), and within this framework we examine the effectiveness of an axial jet injection for mitigating the flow instability. It is shown that a limited number of modes can be used to reconstruct the flow field. Moreover, POD enables to reveal influence of the jet injection on the individual modes of the flow and illustrates continuous suppression of the modes from higher-order modes to lower-order modes as the jet discharge increases. Application of POD offers new view for the future control effort aimed on vortex rope mitigation because spatiotemporal description of the flow is provided. Thereby, POD enables better focus of the jets or other flow control devices.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10305 - Fluids and plasma physics (including surface physics)

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2017

Confidentiality

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

Name of the periodical

JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME

ISSN

0098-2202

e-ISSN

1528-901X

Volume of the periodical

139

Issue of the periodical within the volume

8

Country of publishing house

US - UNITED STATES

Number of pages

25

Pages from-to

1-25

UT code for WoS article

000403876900001

EID of the result in the Scopus database

2-s2.0-85019637867