The modelling of a flap type wave energy converter in a time-dependent mild-slope equation model

International audienceThe accurate modelling of the wave field distribution around Wave Energy Convertors (WECs) has been a relevant subject of research in the recent years. Interaction effects in the wave field surrounding the devices are important to know either for power production optimisation of an array or for the quantification of its wake effect due to the absorption of the incoming wave energy. A considerable amount of works have studied arrays of WECs employing methodologies such as BEM based on potential flow theory, wave propagation models, or even CFD in some cases. This study presents an investigation on the modelling of the perturbed wave field by a flap type WEC in a time-dependent mild-slope equation model. The aim of this work is to verify the implementation of a flap in a mild-slope equation model against the wave field obtained from a BEM. Several regular wave cases show the results for different modelling techniques. The capability of modelling the diffracted wave intrinsically in the mild-slope equation model and the implementation of a coupling technique with a BEM are shown. In the last section a representation of the flap by applying the sponge layer technique is done. The understanding of all these techniques with their advantages and disadvantages is relevant for a further development of the wave field modelling. The improvement of the state of the art would allow to quantify more accurately the wake effect of a WEC farm and thus evaluate their capability of acting as a shield with respect to the incoming wave field