On the hydrostatic nonlinearity of spar type floating offshore wind turbine

Abstract

The stability of the floating wind turbine against complex environmental loadings is one of the major challenges in the development of the floating wind turbine industry. Hydrostatics of floating wind turbine is one of the main sources of stability of the floating structure. The use of linear hydrostatic stiffness is very common in the analysis of floating wind. In this paper, nonlinear hydrostatic stiffness is obtained for a floating spar platform, taking into account the rotational displacement of the platform. The dynamic equation of motion of the floating wind turbine is formulated using Newton-Euler approach. The mooring lines are modeled using the elastic catenary cable element. The hydrodynamic forces on the floating platform are calculated using Morison's equation. The effect of hydrostatic nonlinearity on the dynamic response of the floating offshore wind turbine through the analysis of OC3-Hywind model. The results show a significant effect of hydrostatic nonlinearity on the amplitude of heave displacement. © ASCE.