Load Fluctuations and Response of Rotor Systems in Turbulent Wind Fields

摘要

A frequency domain model was developed to take time and space dependence of incoming wind turbulence into account, to determine the apparent wind speed fluctuations for a rotating wind turbine blade, and the consequent load fluctuations. Wind speed and load fluctuations are described in frequency spectra, expanded in rotational modes centered around the harmonics of the rotation frequency. Similar expansions apply to flexible rotor systems, where frequency filters appear due to flapping blade motions. This is demonstrated for a hinged blade rotor. The filters are characterized by physical blade parameters like mechanical, centrifugal and aerodynamic stiffness, and aerodynamic damping. Calculated spectra, and fatigue damage rate estimations are presented. Applications and limitations of the model are discussed.