Numerical and experimental study of the effects of WEC motion on a combined wind-wave energy platform

초록

In this study, the motion response of a combined wind-wave energy platform equipped with multi wave energy converters (WEC) that can control the motion of a floating offshore wind turbine (FOWT) was analyzed numerically and verified through a two-dimensional mini wave tank experiment. The combined energy platform attaching the WEC to the FOWT not only produces stable energy by controlling the motion of the FOWT with the motion of the WEC, but also produces wave energy by the relative motion of the WEC. The FOWT is a taut mooring spar-type platform, and the WEC is a moving cylinder hinged to the FOWT. The motion reduction effect of the FOWT by the motion of the WEC was analyzed. Numerical analysis used a potential flow-based hydrodynamic program (AQWA). To estimate the restraining force of the FOWT due to the motion of the WEC, the multibody dynamics theory was applied, and the accuracy of the numerical model was improved by applying mooring dynamics, weakly nonlinear Froude-Krylov force, and nonlinear hydrostatic force. The experimental model was fabricated on a scale of 1/100 of the numerical model and was performed in a two-dimensional mini wave tank. The numerical analysis results were in good agreement with the experimental results. In particular, the pitch of FOWT by the motion of WEC significantly decreased near the pitch resonance area. Using the verified numerical model, the behaviour of the combined energy platform due to the motion of the WEC under various wave conditions was analyzed in detail. © 2023 European Wave and Tidal Energy Conference.

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