Identification of aerodynamic damping matrix for operating wind turbines

Accurate knowledge of wind turbine tower vibration damping is essential for the estimation fatigue life. However, responses in fore-aft and side-side directions are coupled through wind-rotor interaction under operational conditions. This causes energy transfers complicates aerodynamic identification using conventional ratios. Employing a reduced two-degree freedom model developed this paper, coupling can be accurately expressed by an unconventional matrix. Simulated time series obtained from were successfully verified against outputs simulation tool FAST. Based on system obtained, matrix-based method proposed to identify numerically simulated responses. Applying harmonic excitations allowed frequency response functions matrix extracted. Results compared traditional modal analysis methods including standard modified stochastic subspace identification. The direction was identified all methods, but results showed that performs better capturing