Hydrodynamic Performance and Energy Capture Characteristics of a Floating Inner Rotor Wave Energy Device

The development of efficient wave energy converters (WECs) is essential for harnessing marine renewable energy, particularly in regions with low wave energy flux. This study investigates a floating WEC with an internal eccentric rotor designed to enhance energy capture efficiency. The device consists of a floating body for wave energy absorption, an internal rotor for mechanical-to-hydraulic energy conversion, and a mooring system for stability. A numerical model was developed and validated against wave tank experiments, showing good agreement in peak values and amplitudes. Frequency-domain analysis examined the effects of structural parameters, draft, and center of gravity offset on hydrodynamic characteristics, while time-domain analysis evaluated the impact of rotor mass and power take-off (PTO) damping on energy capture. Multi-parameter optimization led to an improved structural design, increasing instantaneous power output by 150% and total power output by 108%. These findings provide a basis for further optimization of WECs in low-energy wave environments.