This paper presents the validation of ADCoS-Offshore, a newly developed design tool for simulation of offshore wind turbines (OWT). ADCoS-Offshore allows the modeling of branched support structures as Finite Element (FE) beam models in a fully coupled simulation of overall turbine dynamics and it is validated within the Offshore Code Comparison Collaboration (OC3). OC3 is part of the International Energy Agency Wind Annex XXIII. Within this project a realistic 5 MW wind turbine with a tripod substructure is modeled and a set of load cases is run by different partners with several design tools. In this way the performance of ADCoS-Offshore is shown. Furthermore the impact of various modeling assumptions is shown.
The potential of Offshore Wind Energy to deliver cost effective green energy is immense, therefore important steps are taken all over the world to promote this technology. The size of the offshore wind turbines (OWT) is still increasing and offshore wind farms are situated in deeper and deeper waters. For these reasons, the established monopile and gravity based foundations become more and more inappropriate and complex branched support structures are developed and tested as prototypes. Only detailed simulation of such turbines with extensively tested numerical tools can lead to reliable load assumptions. This is of vital importance for reliable and cost effective production of current and future turbines. The described load simulation is a complex task as it has to take the loads from wind and water waves, the turbine control system, the highly dynamic structure of the turbine and the interactions between all subsystems into account. This leads to the use of so called aerohydro- servo-elastic tools. Parallel to the development of new support structure types, the described simulation tools are extended to allow for simulation including those structures and subsequently they are comprehensively tested.