Development of coupling module between BHawC aeroelastic software and OrcaFlex for coupled dynamic analysis of floating wind turbines

Floating Offshore Wind Turbines (FOWTs) dynamic analysis can be quite challenging as it requires to model within the same calculation aerodynamics, hydrodynamics, controller, moorings and structure behaviour. Mooring and anchor design are strongly affecting FOWTs dynamic behaviour. Also, floater structural behaviour can be complex to model in a decoupled finite element analysis software. To do so, Innosea and Siemens Gamesa Renewable Energy developed a coupling between BHawC software and OrcaFlex software. BHawC is a nonlinear aeroelastic tool performing dynamic analysis of wind turbines. OrcaFlex is a generalist offshore marine engineering software that can perform the dynamic analysis of floaters and their mooring system. This paper describes the method and the mathematical background that is used to perform detailed time-domain simulations of a floating wind turbine coupling BHawC and OrcaFlex. The coupling is verified comparing time domain simulations on several load cases for rigid floaters coupled to a turbine with a rigid RNA. This shows a good agreement which confirms the correctness of the coupling.