Experimental and computational damping estimation of an offshore wind turbine on a monopile foundation

In this study, Operational Modal Analysis (OMA) is used to identify the damping value of the fundamental for-aft (FA) mode of an Offshore Wind Turbine (OWT) using both real life measurements and simulations. Estimations of the total damping of an offshore wind turbine (taking into account the effects of the aerodynamic, hydrodynamic and soil loads) give a quantitative view of the stability characteristics of the wind turbine. Two different test cases including an overspeed stop and ambient excitation have been considered. The experimental data has been obtained during a measurement campaign on an offshore wind turbine in the Belgian North Sea and the results are compared with the numerical simulations which have been carried out in HAWC2.