Analysis and Validation of Glauert Rotor Design

Jens N. Sørensen*, Néstor Ramos-García, Valéry L. Okulov

*Corresponding author for this work

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

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The design of industrial wind turbine rotors is generally based on the blade-element/momentum (BEM) approach introduced by Glauert (1935). Essentially, the theory consists of combining a blade-element approach with axial momentum theory, and then introducing a tip correction to account for the finite number of rotor blades. This is required, as the momentum theory is based on representing the rotor by a disk, corresponding to a rotor with infinitely many blades. The optimum design properties are obtained by optimizing the local power coefficient at each blade element. This is typically accomplished by solving a simple analytical system of equations for the axial and tangential inductions factors, ignoring at first the tip correction. The tip correction is subsequently introduced to correct the design variables. In the present work we analyse the implications of including the tip correction directly in the optimization. As a result of the analysis, we find the somewhat surprising result that the maximum optimal interference factor is not 1/3, as normally encountered for optimum rotor design, but 2/5. In the paper we prove this analytically and use the theory to design optimum rotors, which subsequently are benchmarked by comparison to results from a numerical lifting line model.
Original languageEnglish
Title of host publicationTurbine Technology; Artificial Intelligence, Control and Monitoring
Number of pages11
PublisherIOP Publishing
Publication date2022
Article number032047
Publication statusPublished - 2022
EventThe Science of Making Torque from Wind 2022 - Delft, Netherlands
Duration: 1 Jun 20223 Jun 2022
Conference number: 9


ConferenceThe Science of Making Torque from Wind 2022
Internet address
SeriesJournal of Physics: Conference Series


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