The importance of wind turbulence and coherence to the loads on a wind turbine blade

Abstract

The wind simulation method proposed by Paul S. Veers from Sandia National Laboratories has been checked for the measured wind velocities at 40m and 80m height at FINO1 platform. The Sandia method applied as it is, gives relatively higher standard deviation (turbulence) than the actual but works better when random phases are used. A code for the generation of wind field based on Sandia method has been developed from a time series of wind speed at hub center. Various wind fields based on difference in wind shear and turbulence intensity have been projected on to the reference wind turbine to find root bending moments of the blade. The bending moments are calculated based on 2D Beam Element Momentum theory. The mean bending moment values are affected by wind shear while the maximum bending moments by turbulent intensity. An increase in turbulence in the wind field will increase the maximum and standard deviation of flap-wise bending moment drastically.