On the importance of restoring term approximations for large pitching floating devices

The improvements of this methodology are compared with the classical approach of using a constant hydrostatic matrix based on precomputed values at equilibrium. A wave energy converter (WEC) designed to extract energy through large rotations is employed to analyze the effect of non-linearizing the hydrostatic term. The results of the methodology for static conditions are validated using commercial software. A sensitivity analysis of the panelization used is also presented. A comparison of the computed results of all the methods using laboratory data shows the improvement of the results when non-linear approximations are used. In the laboratory large amplitude rotations display a different period than small amplitude rotations. This effect cannot be reproduced by the classical linear model but it can be reproduced by non-linear hydrostatic models.