Midfidelity model verification for a point-absorbing wave energy converter with linear power take-off

In the preliminary design stage of a waveenergy converter (WEC), researchers need fast and reliablesimulation tools. High-fidelity numerical models are usu-ally employed to study the wave-structure interaction, butthe computational cost is demanding. As an alternative,midfidelity models can provide simulations in the order ofreal time. In this study, we operate Uppsala University’sWEC in a relatively mild sea state and model it usingWEC-Sim. The model is verified based on OpenFOAMsimulations. To analyze the ability of the midfidelitymodel to capture WEC dynamics, we investigate the systemseparately with 1, 2, and 3 degrees of freedom. We examinethe contribution of viscous phenomena, and study bothlinear and weakly nonlinear solutions provided by WEC-Sim. Our results indicate that the viscous effects can beneglected in heave and surge motion, but not for pitch.We also find that the weakly nonlinear WEC-Sim solutionsuccessfully agrees with the computational fluid dynam-ics, whereas the linear solution could suggest misleadingresults.