What effect does downwash and wing tip vortex have on the angle-of-attack?
A. The wing tip vortex changes the downwash and therefore angle-of-attack along the blade. Aircraft wings use an elliptical planform to minimise the variation in angle-of-attack due to downwash. The turbine blade design should make similar computations to optimise efficiency. The extra induced drag caused by downwash is currently computed by the program but not yet the chord width or angle changes needed to compensate for it.
