A Gust Model for Wind Turbine Design

A new method, so called constrained stochastic simulation, has been developed in order to generate extreme gust time series, to be used to calculate the extreme loading of wind turbines. A constrained simulation corresponds to the addition, in a special manner, of turbulence and a deterministic part (which resembles the auto correlation function of turbulence). The stochastic gusts produced in this way has been denoted NewGust and it is proved that they are, in a statistical sense, not distinguishable from gusts selected from a (very long) stochastic time series, with the same amplitude. The NewGust method forms a part of on overall probabilistic method to determine the distribution of the wind turbine response on gusts. This new probabilistic method enables wind turbine manufacturers to build more reliable and optimised wind turbines. The theoretical mean gust shape, as well as the probability of occurrence of gusts, has been verified by measurements. In addition preliminary comparisons between numerical load simulations and wind turbine load measurements have been carried out.