An Open Database of High-Fidelity, Multi-Reynolds Airfoil Polars for Wind Turbine Blade Design
Abstract. This paper presents an open-access dataset that has been realized to provide high-fidelity aerodynamic polars for a wide range of wind turbine airfoils, computed using a consistent Computational Fluid Dynamics (CFD) methodology. The database includes lift, drag, and moment coefficients across multiple Reynolds and Mach numbers. Coefficients are computed with both fully turbulent and free transition boundary layers. A blend of the free transition and fully turbulent coefficients is also included. Beyond the stall region, state-of-the-art post-stall extrapolation models are used, the calibration parameters of which are derived from a number of high-fidelity calculations at various angles of attack in separated flow. The data is relevant for wind turbine design, modeling, and simulation, and reflects representative airfoil performance along the span of modern, large-size offshore rotors. The database includes FFA-W3, FFA-W2, FFA-W1, DU, FX-77 and the recently developed OSO families of airfoils. All simulations are performed using validated numerical methods and span a range of conditions typical for utility-scale offshore turbines. The paper discusses the dataset and its key differences with other open-access data, as well as some general trends that can be noted in the aerodynamic coefficients; such a discussion is made possible by the volume of data produced and is specifically tailored to wind turbine applications.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Wind Energy Science.
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In this paper, the authors conduct high-fidelity URANS simulations on different airfoil families to determine the aerodynamic coefficients under a wide variety of operating conditions. Overall, the current research contributes to improving the understanding of blade design and efficiency using new types of airfoils and providing a complete database to be used by the community for this purpose. Before conducting the final simulations, the authors carefully conduct domain, grid and timestep sensitivity analyses. The data set provides a solid foundation for future research to build upon and offers novelty by incorporating compressibility effects. However, the main weakness of the paper is the lack of clarity in several key justifications or model assumptions, which makes the computational setup and results difficult to interpret.
After reviewing the manuscript, I have grouped my comments into two categories, major concerns and minor corrections/suggestions.
Major comments:
Minor comments:
Overall, the manuscript needs major changes and rewriting before considering for publication. If all comments as described above are addressed, I recommend that the manuscript should be accepted.