Round robin tests on a hinged raft wave energy converter

One of the main goals of the EU H2020 MaRINET2 project is to improve the quality, robustness and accuracy of physical modelling and testing practices operated by MaRINET2 infrastructures. To achieve this objective, a round robin testing program has been developed where the same device is tested in a number of different infrastructures. The outcomes are new, robust and representative sets of standardised testing procedures and the delivery of open access datasets for virtual laboratory calibration and verification. This paper describes the tests on a wave energy converter model carried out in the wave tanks of University of Plymouth, University College Cork, University of Edinburgh and Centrale Nantes. This deep water device selected by the partners is a two-body hinged raft modelled at a scale of 1:25. Centrale Nantes designed and built the model and developed its Power Take Off (PTO) servo control. The PTO emulator produces a dynamically controlled linear damping law. The PTO resisting torque is proportional to the angular velocity of the relative pitch motion between the two floaters. A real time embedded controller monitors and controls the PTO to ensure correct dynamic behaviour. A simple mooring setup using calibrated springs and aerial lines was designed to fit all the facilities. The wave test program was informed by the wave generation capacities of the infrastructures. Partners worked together to establish a common data format and a common analysis methodology to share and compare the measurements and the analysis results. This paper describes the model, the experimental setups in each facility, and the methodology used for data analysis. The results for the regular wave tests from all infrastructures are compared and discussed.