Comparison of dynamic stall on an airfoil undergoing sinusoidal and VAWT-shaped pitch motions

C. E. Brunner, J. Kiefer, M. Hultmark*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

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Abstract

The aerodynamics of vertical axis wind turbines (VAWTs) are inherently unsteady because the blades experience large angle of attack variations throughout a full turbine revolution. At low tip speed ratios, this can lead to a phenomenon known as dynamic stall. To better characterise the unsteady aerodynamics and represent them in models and simulations, data from studies of individual static or pitching airfoils are often applied to VAWT blades. However, these studies often involve sinusoidally pitching airfoils, whereas the pitching motions experienced by VAWTs are more complex. Here, the pressures and forces on an airfoil undergoing VAWT-shaped pitch motions corresponding to various tip speed ratios are compared to those of a sinusoidally pitching airfoil in order to assess whether a sinusoidal motion represents a reasonable approximation of the motions of a VAWT blade. While the lift development induced by the sinusoidal motion yields good agreement with that induced by the VAWT-shaped motion at the higher tip speed ratios, notable discrepancies exist at the lower tip speed ratios, where the VAWT motion itself deviates more from the sinusoid. Comparison with sinusoidal motions at reduced frequencies corresponding to the upstroke or downstroke of the VAWT-shaped motion yield better agreement in terms of the angle of stall onset.
Original languageEnglish
Title of host publicationTurbine Technology; Artificial Intelligence, Control and Monitoring
Number of pages10
PublisherIOP Publishing
Publication date2022
Article number032006
DOIs
Publication statusPublished - 2022
EventThe Science of Making Torque from Wind 2022 - Delft, Netherlands
Duration: 1 Jun 20223 Jun 2022
Conference number: 9
https://www.torque2022.eu/

Conference

ConferenceThe Science of Making Torque from Wind 2022
Number9
Country/TerritoryNetherlands
CityDelft
Period01/06/202203/06/2022
Internet address
SeriesJournal of Physics: Conference Series
Number3
Volume2265
ISSN1742-6596

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