Experimental validation of numerically generated wave excitation torque on an OWSC

Hydrodynamic models can be used to predict wave energy converter performance, loading and ultimately their potential revenue. A key term in a wave energy converter’s numerical model, and therefore one that requires careful validation, is the wave excitation term. A study was carried out at Queen’s Universi- ty Belfast to validate the excitation torque calculated for a flap, similar in shape to an OWSC, by two bounda- ry element codes, Nemoh and WAMIT. Physical tests show both Nemoh and WAMIT to have reasonably good agreement when predicting the reaction torque of the fixed flap to the excitation of monochromatic waves. The tests also highlight certain conditions in which their predictions break down. Differences, between what the BEM codes predict and what is observed in the experiments, were found to occur when the flap’s top edge was near to the still water’s surface and when in the presence of either long or steep waves.