On the laminar–turbulent transition mechanism on megawatt wind turbine blades operating in atmospheric flow
Publication date
2023-03-06
Document type
Research article
Author
Lobo, Brandon Arthur
Özçakmak, Özge Sinem
Madsen, Helge Aagaard
Schaffarczyk, Alois Peter
Sørensen, Niels N.
Organisational unit
Series or journal
Wind Energy Science
Periodical volume
8
Periodical issue
3
First page
303
Last page
326
Peer-reviewed
✅
Part of the university bibliography
✅
Keyword
Laminar–turbulent transition on wind turbine blades
Abstract
Among a few field experiments on wind turbines for analyzing laminar–turbulent boundary layer transition, the results obtained from the DAN-AERO and aerodynamic glove projects provide significant findings. The effect of inflow turbulence on boundary layer transition and the possible transition mechanisms on wind turbine blades are discussed and compared to CFD (computational fluid dynamics) simulations of increasing fidelity (Reynolds-averaged Navier–Stokes, RANS; unsteady Reynolds-averaged Navier–Stokes, URANS; and large-eddy simulations, LESs). From the experiments, it is found that the transition scenario changes even over a single revolution with bypass transition taking place under the influence of enhanced upstream turbulence, for example, such as that from wakes, while natural transition is observed in other instances under relatively low inflow turbulence conditions. This change from bypass to natural transition takes place at azimuthal angles directly outside the influence of the wake indicating a quick boundary layer recovery. The importance of a suitable choice of the amplification factor to be used within the eN method of transition detection is evident from both the RANS and URANS simulations. The URANS simulations which simultaneously check for natural and bypass transition match very well with the experiment. The LES predictions with anisotropic inflow turbulence show the shear-sheltering effect and a good agreement between the power spectral density plots from the experiment and simulation is found in case of bypass transition. A condition to easily distinguish the region of transition to turbulence based on the Reynolds shear stress is also observed. Overall, useful insights into the flow phenomena are obtained and a remarkably consistent set of conclusions can be drawn.
Cite as
Wind Energ. Sci., 8, 303–326, 2023
Version
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