Gust modelling for wind loading

Abstract

In this paper the TNO gust analysis method and the resulting TNO gust model are described. The method has been applied to a set of 700 hours of stationary wind speed time series measured at the meteorological mast at Cabauw, The Netherlands. The results are discussed in this paper. The TNO gust model has been developed for the calculation of wind turbine loads, especially fatigue loads. To model gusts an analysis method has been developed to statistically analyze full-scale wind speed data and translate these to discrete gusts. The main result of the TNO gust model is that finally, all gust amplitudes are described by one single expression being a function of the height, the mean wind speed, the turbulence intensity, the gust duration and the probability exceedance level within an error band of less than 5%. The model also gives a relation between the gust duration and the frequency of occurence of the gusts. The TNO gust model has been incorporated in the Dutch Handbook ‘Wind Data for Wind Turbine Design’. Verification of this handbook has been performed by comparing the flap and lag loads on the blade root of three different wind turbines by means of the Handbook with the loads measured. The comparison showed very good agreement especially in the range 10 2 to 10 8 load fluctuations per year.