Reynolds number extrapolation for wind turbine airfoil polars: a data-driven approach

Özgören, Ahmet Can
In this thesis, a data-driven methodology based on power law is proposed to extrapolate the Reynolds number, and its prediction performance for wind turbine airfoil aerodynamic polars are investigated. For this purpose, a database is constructed from experimentally obtained aerodynamic data from open literature for airfoils with thickness-to-chord ratio (t/c) values in the range of 15% to 30%, which are more relevant to wind turbine blade design applications. The airfoils included in the database are inversely parameterized using the PARSEC airfoil parameterization method to enhance the database numerically in terms of the geometrical properties. Then, Pareto analysis is performed to understand the sensitivity of maximum lift coefficient (Clmax) and minimum drag coefficient (Cdmin) variations to PARSEC geometrical properties as well as the Reynolds number using JMP statistical software. Based on this analysis, response surfaces are generated to predict Clmax and Cdmin of a given airfoil operating at a given Reynolds number. These predicted values are then utilized in a proposed power law based estimation methodology to obtain predictions for the full polars. This proposed method is tested by making predictions for airfoils divided into two groups: those that are included in the database and those that are not. At last, predicted aerodynamic polars for the FFA-W3-241 airfoil are implemented in aeroelastic BEM simulations to investigate their effects on the operation of the DTU 10 MW reference wind turbine.


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Citation Formats
A. C. Özgören, “Reynolds number extrapolation for wind turbine airfoil polars: a data-driven approach,” M.S. - Master of Science, Middle East Technical University, 2023.