Prediction of Aerodynamic Loads for NREL Phase VI Wind Turbine Blade in Yawed Condition
Ki-Wahn Ryu, Seung-Hee Kang, Yun-Ho Seo and Wook-Ryun Lee
International Journal of Aeronautical and Space Sicences, vol. 17, no. 2, pp.157-166, 2016
Abstract : Aerodynamic loads for a horizontal axis wind turbine of the National Renewable Energy Laboratory (NREL) Phase VI rotor in
yawed condition were predicted by using the blade element momentum theorem. The classical blade element momentum
theorem was complemented by several aerodynamic corrections and models including the Pitt and Peters¡¯ yaw correction,
Buhl¡¯s wake correction, Prandtl¡¯s tip loss model, Du and Selig¡¯s three-dimensional (3-D) stall delay model, etc. Changes of
the aerodynamic loads according to the azimuth angle acting on the span-wise location of the NREL Phase VI blade were
compared with the experimental data with various yaw angles and inflow speeds. The computational flow chart for the
classical blade element momentum theorem was adequately modified to accurately calculate the combined functions of
additional corrections and models stated above. A successive under-relaxation technique was developed and applied to
prevent possible failure during the iteration process. Changes of the angle of attack according to the azimuth angle at the
specified radial location of the blade were also obtained. The proposed numerical procedure was verified, and the predicted
data of aerodynamic loads for the NREL Phase VI rotor bears an extremely close resemblance to those of the experimental
data.
Keyword : horizontal axis wind turbine, aerodynamic loads, NREL Phase VI rotor, blade element momentum theorem (BEMT) |