Unsteady effects on a pitching airfoil at conditions relevant for large vertical axis wind turbines

C. E. Brunner, J. Kiefer, M. O.L. Hansen, M. Hultmark

Research output: Contribution to journalConference articlepeer-review

3 Scopus citations


Interest in offshore vertical axis wind turbines (VAWTs) has created a need to study VAWTs at much higher Reynolds numbers than they have previously been studied at. VAWTs are characterised by unsteady aerodynamics, and high Reynolds numbers have the potential to alter the blade aerodynamics significantly. Here, results are reported on an airfoil that is pitched sinusoidally around zero angle of attack at Rec = 1 × 106, at a reduced frequency k = 0.15 and amplitudes of 5? < α < 20?. Since the static stall angle is not exceeded, no stall effects occur. Nevertheless, lift, drag and moment coefficients show noticeable hysteresis. Despite the high amplitudes of oscillation, lift and moment coefficients show reasonable agreement with unsteady aerodynamic theories by Theodorsen and Motta et al. with regard to the width of the hysteresis loops, but have noticeably steeper slopes.

Original languageEnglish (US)
Article number052065
JournalJournal of Physics: Conference Series
Issue number5
StatePublished - Sep 22 2020
EventScience of Making Torque from Wind 2020, TORQUE 2020 - Virtual, Online, Netherlands
Duration: Sep 28 2020Oct 2 2020

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


Dive into the research topics of 'Unsteady effects on a pitching airfoil at conditions relevant for large vertical axis wind turbines'. Together they form a unique fingerprint.

Cite this