Characterizing the Helical Vortex Frequency of HAWT

2020 ◽  
pp. 611-620
Author(s):  
Ojing Siram ◽  
Niranjan Sahoo
Keyword(s):  
Helical Vortex

scholarly journals Kelvin waves on helical vortex tube in swirling flow

2018 ◽  
Vol 980 ◽  
pp. 012003
Author(s):  
M A Tsoy ◽  
S G Skripkin ◽  
P A Kuibin ◽  
S I Shtork ◽  
S V Alekseenko
Keyword(s):  
Vortex Tube ◽  
Swirling Flow ◽  
Kelvin Waves ◽  
Helical Vortex

scholarly journals Instability and merging of a helical vortex pair in the wake of a rotor

2021 ◽  
Vol 1934 (1) ◽  
pp. 012007
Author(s):  
D Schröder ◽  
T Leweke ◽  
R Hörnschemeyer ◽  
E Stumpf
Keyword(s):  
Vortex Pair ◽  
Helical Vortex

scholarly journals The velocity field induced by a helical vortex tube

2005 ◽  
Vol 17 (10) ◽  
pp. 107101 ◽  
Author(s):  
Y. Fukumoto ◽  
V. L. Okulov
Keyword(s):  
Velocity Field ◽  
Vortex Tube ◽  
Helical Vortex

Hydraulic Instability Onset Detection in Kaplan Turbines by Monitoring Shaft Vibrations

2012 ◽  
Author(s):  
P. Pennacchi ◽  
P. Borghesani ◽  
S. Chatterton ◽  
A. Vania
Keyword(s):  
Experimental Test ◽  
Turbine Unit ◽  
Swirling Flow ◽  
Draft Tube ◽  
Operating Conditions ◽  
Low Flow ◽  
Operating Life ◽  
Vortex Rope ◽  
Power Load ◽  
Helical Vortex

Design of hydraulic turbines has often to deal with hydraulic instability. It is well-known that Francis and Kaplan types present hydraulic instability in their design power range. Even if modern CFD tools may help to define these dangerous operating conditions and optimize runner design, hydraulic instabilities may fortuitously arise during the turbine life and should be timely detected in order to assure a long-lasting operating life. In a previous paper, the authors have considered the phenomenon of helical vortex rope, which happens at low flow rates when a swirling flow, in the draft tube conical inlet, occupies a large portion of the inlet. In this condition, a strong helical vortex rope appears. The vortex rope causes mechanical effects on the runner, on the whole turbine and on the draft tube, which may eventually produce severe damages on the turbine unit and whose most evident symptoms are vibrations. The authors have already shown that vibration analysis is suitable for detecting vortex rope onset, thanks to an experimental test campaign performed during the commissioning of a 23 MW Kaplan hydraulic turbine unit. In this paper, the authors propose a sophisticated data driven approach to detect vortex rope onset at different power load, based on the analysis of the vibration signals in the order domain and introducing the so-called “residual order spectrogram”, i.e. an order-rotation representation of the vibration signal. Some experimental test runs are presented and the possibility to detect instability onset, especially in real-time, is discussed.

Applications of 2D helical vortex dynamics

2009 ◽  
pp. 411-417
Author(s):  
Valery L. Okulov ◽  
Jens N. Sørensen
Keyword(s):  
Vortex Dynamics ◽  
Helical Vortex

scholarly journals Velocity and pressure fluctuations induced by the precessing helical vortex in a conical diffuser

2014 ◽  
Vol 22 (3) ◽  
pp. 032009 ◽  
Author(s):  
A Javadi ◽  
A Bosioc ◽  
H Nilsson ◽  
S Muntean ◽  
R Susan-Resiga
Keyword(s):  
Pressure Fluctuations ◽  
Conical Diffuser ◽  
Helical Vortex

scholarly journals Evolution and breakdown of helical vortex wakes behind a wind turbine

2014 ◽  
Vol 555 ◽  
pp. 012077 ◽  
Author(s):  
A Nemes ◽  
M Sherry ◽  
D Lo Jacono ◽  
H M Blackburn ◽  
J Sheridan
Keyword(s):  
Wind Turbine ◽  
Helical Vortex
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