International audienceThe choice of control strategy for Direct Wave Energy Converters (DWEC) is often discussed without taking into account the limitations of electric Power Take-Off (PTO): limits of torque or force and power, as well as losses in the electric chain. These assumptions leads to large and expensive electric systems, that prevent leading to a global minimization of the per-kWh cost. We propose herein a simple loss model in order to design a better control strategy

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In this study, the mathematical expressions and numerical methods for the free-surface Green function of the linearized wave-structure problem in deep water and in the frequency domain are investigated. Twelve different expressions are reviewed and analyzed. All these expressions are exact mathematical solutions for the propagation of waves from a pulsating source located in the fluid domain. However, their numerical evaluation is challenging. Dedicated numerical methods have been developed. They include series expansions, polynomials, table interpolations, multipole expansions, approximations with elementary functions, etc. In this work, four methods were implemented: the Newman's method [1], the Delhommeau's method [2], the Telste-Noblesse's method [3] and the Wu et al.'s method [4]. Their CPU time and accuracy are compared. It is found that the average computational time for Newman's method is 5.745×10 −7. It is 5.782 × 10 −8 for the Delhommeau's method. For Telste-Noblesse's method and Wu et al.'s methods, they are 4.642 × 10 −8 and 1.491 × 10 −9 , respectively. The accuracy is respectively 6D(6 decimals), 5D and 3D for the Newman's method, the Telste-Noblesse's method and the Wu et al.'s method. For the Delhommeau's method, it is 3D except when the vertical coordinate is close to 0. The accuracy of the Delhommeau's method can be increased significantly by