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

Abstract

In the preliminary design stage of a wave
energy converter (WEC), researchers need fast and reliable
simulation tools. High-fidelity numerical models are usu-
ally employed to study the wave-structure interaction, but
the computational cost is demanding. As an alternative,
midfidelity models can provide simulations in the order of
real time. In this study, we operate Uppsala University’s
WEC in a relatively mild sea state and model it using
WEC-Sim. The model is verified based on OpenFOAM
simulations. To analyze the ability of the midfidelity
model to capture WEC dynamics, we investigate the system
separately with 1, 2, and 3 degrees of freedom. We examine
the contribution of viscous phenomena, and study both
linear and weakly nonlinear solutions provided by WEC-
Sim. Our results indicate that the viscous effects can be
neglected in heave and surge motion, but not for pitch.
We also find that the weakly nonlinear WEC-Sim solution
successfully agrees with the computational fluid dynam-
ics, whereas the linear solution could suggest misleading
results.