Investigation of Stability Effects of an Offshore Wind Turbine

The article describes work to investigate the effects on tower dynamics when mounting a turbine on a monopile foundation offshore compared to a similar onshore installation. Changes in frequency, mode shapes and damping were investigated, including effects of hydrodynamics and non-linear soil properties. The tool used for the investigation is the new aeroelastic code HAWC2, which is based on a multibody formulation. This formulation is very general, which means that it can handle any structural object (body) as well as large rotations between the bodies and their associated non-linear effects. Thus, for example, complex foundation types such as very flexible monopile foundations, tripod structures and even floating support structures can be simulated in the code.