Expanding Operational Bandwidth and Tuning a Wave Energy Converter Using U-shaped Sloshing Tanks

The ocean is the largest untapped energy site in the world and the recent decades have shown promising developments towards the wave energy converters (WEC). Among the problems related to the WECs are surely the optimal control strategy and the reliability in extreme waves conditions, and certainly also the tuning of the device, which due to the intrinsic nature of the sea will have to face wildly variable conditions compared to the nominal ones for which it was designed. This work aims to investigate the capability of tuning WECs through a U-shaped tuned liquid damper, expanding its operational bandwidth. To do this, a simply modified 1-D model of the U-tank coupled to the WEC is presented. The model has been validated by an experimental campaign concerning both kinematics, acquiring the water level via a motion tracking system, and dynamics, through load cells. The carried-out results show a good fit with the experiments both in regular and irregular imposed motion.