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Multi-purpose offshore structures are very complex systems to be designed as many different requirements have to be taken into account simultaneously. Experimental tests on scaled models can be very useful to verify structural behavior and to validate numerical models. The definition of the scale can play a key role in performing tests as high scales, closer to full-scale, are generally related to more reliable results. The present paper concerns the design of a wind turbine model for a large-scale model of a Multi-purpose offshore Platform developed within the EU project H2020 Blue Growth Farm. This project aims at developing an offshore farm, based on a modular floating structure that integrates wave energy converters and a wind turbine with aquaculture. The scale model of the complete structure will be deployed at the Natural Ocean Engineering Laboratory (NOEL). The paper will focus on the strategies adopted to scale 1:15 the DTU 10 MW wind turbine in order to represent both the main aeroelastic features and all the functionalities of a real machine. The complete design of the machine and its control will be also provided.

The present paper describes the experiences gained from the design methodology and operation of a 3D physical modelexperiment aimed to investigate the dynamic behaviour of a spar buoy floating offshore wind turbine. The physical model consists in a Froude-scaled NREL 5MW reference wind turbine (RWT) supported on the OC3-Hywind floating platform. Experimental tests have been performed at Danish Hydraulic Institute (DHI) offshore wave basin within the European Union-Hydralab+ Initiative, in April 2019. The floating wind turbine model has been subjected to a combination of regular and irregular wave attacks and different wind loads. Measurements of displacements, rotations, accelerations, forces response of the floating model and at the mooring lines have been carried out. First, free decay tests have been analysed to obtain the natural frequency and the modal damping ratios of each degree of freedom governing the offshore. Then, the results concerning regular waves, with orthogonal incidence to the structure, are presented. The results show that most of longitudinal dynamic response occurs at the wave frequency and most of lateral dynamic response occurs at rigid-body frequencies. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654110, HYDRALAB+.

The present paper describes the experiences gained from the design methodology and operation of a 3D physical model experiment aimed to investigate the dynamic behaviour of a spar buoy (SB) off-shore floating wind turbine (WT) under different wind and wave conditions. The physical model tests have been performed at Danish Hydraulic Institute (DHI) off-shore wave basin within the European Union-Hydralab+ Initiative, in April 2019. The floating WT model has been subjected to a combination of regular and irregular wave attacks and wind loads.