Gyroscopic effects on a large vertical axis wind turbine mounted on a floating structure

This paper presents an analysis technique for investigating the effects of gyroscopic couples on the behaviour of a large vertical axis wind turbine mounted on a floating semi-submersible vessel. Equations of motion in 6 degrees of freedom are formulated in the frequency domain. Time domain aerodynamic loads are derived from a double multiple stream tube model based Paraschivoiu [13]. These loads are transposed to the frequency domain and integrated with a formulation of the gyroscopic moments acting for the wind turbine rotating and the semi-submersible rotating in roll and pitch due to ocean waves. The paper uses this model to explore the effect of gyroscopic effects on the motions of the turbine and semi-submersible. It is shown that the gyroscopic effect has negligible effects on some modes of motion but that it introduces significant motions at key frequencies related to rotor speed.

► Impact of gyroscopic couples on the motion of a vertical axis wind turbine. ► Hybrid frequency and time domain technique solving the equation of motion. ► Formulation of the gyroscopic moments in roll and pitch due to ocean waves. ► Effects of gyroscopic couples on the system motions are characterised. ► Gyroscopic effect introduces significant motions at key frequencies.