Gyroscopic effects of the spinning rotor-blades assembly on dynamic response of offshore wind turbines

Abstract

An analytical solution for the gyroscopic effect of the spinning rotor-blades assembly on the dynamic response of offshore wind turbines (OWT) is presented. A continuous coupled model is rigorously developed to form the partial differential equations of fore-aft, side-side, and yaw motions. The gyroscopic moments caused by the angular momentum of the spinning rotor-blades assembly are formulated and handled into the three boundary conditions at the nacelle. The procedure for obtaining the operational natural frequencies of the structure including these coupled boundary conditions is developed. Furthermore, a response function for each fore-aft and yaw motions is obtained by solving the equations of motion under a wave load applied in only the fore-aft direction. Finally, the operational natural frequencies are calculated and compared to the idling ones for the considered example of OWT. The response of the structure under different values of the rotor-blades assembly's angular velocity is investigated. The proposed solution in this study unfolds a revelational procedure in capturing the gyroscopic effect in wind turbine industries which also can be a guideline for developing the floating OWT models.