A high resolution tower shadow model for downwind wind turbines

Abstract

A high resolution model for tower shadow effects on horizontal axis wind turbines has been developed which involves the use of a prescribed wake vortex model and an efficient near wake dynamic model of the vorticity trailed from the blade. The prescribed wake model is applied at first stage of the modelling strategy to provide basic information on blade aerodynamics. The near wake model has been enhanced with appropriate modifications and integrated into an unsteady aerofoil scheme to produce a hybrid method capable of predicting the detailed high resolution unsteady response in the tower shadow region. The computational cost introduced by the high resolution near wake model is almost negligible. Comparisons of the results of the high resolution scheme with measurement show a reasonable level of agreement. The model shows a strong impulsive response of the blade loading when the blade is passing out of the tower shadow, which requires further investigation.