Experimental Update of the Overtopping Model Used for the Wave Dragon Wave Energy Converter

Abstract

An overtopping model specifically suited for Wave Dragon is needed in order to improve the reliability of its performance estimates. The model shall be comprehensive of all relevant physical processes that affect overtopping and flexible to adapt to any local conditions and device configuration. An experimental investigation is carried out to update an existing formulation suited for 2D draft-limited, low-crested structures, in order to include the effects on the overtopping flow of the wave steepness, the 3D geometry of Wave Dragon, the wing reflectors, the device motions and the non-rigid connection between platform and reflectors. The study is carried out in four phases, each of them specifically targeted at quantifying one of these effects through a sensitivity analysis and at modeling it through custom-made parameters. These are depending on features of the wave or the device configuration, all of which can be measured in real-time. Instead of using new fitting coefficients, this approach allows a broader applicability of the model beyond the Wave Dragon case, to any overtopping WEC or structure within the range of tested conditions. Predictions reliability of overtopping over Wave Dragon increased, as the updated model allows improved accuracy and precision respect to the former version.

Keywords

• overtopping
• Wave Dragon
• wave tank testing
• performance assessment
• wave energy
• experimental modeling
• model development