Hydrodynamic characteristics of a wind turbine monopile foundation integrated with an oscillating water column wave energy device

We explore the incorporation of an oscillating water column (OWC) device into a monopile foundation designed for offshore wind power generation. The hydrodynamic characteristics of the structure are investigated, including the free water surface and air pressure response inside the OWC chamber, the wave energy capture performance, and the wave load response under various power take-off (PTO) damping and wave conditions. An orifice is employed to represent the quadratic PTO damping effect. Results indicate that increasing the PTO opening ratio increases the peak frequency of the water surface oscillation coefficient inside the OWC chamber, as well as the OWC pneumatic power. The load-reduction effect of the OWC device in the positive direction is likely related to the water surface oscillation inside the chamber and the wave energy extraction efficiency. At high wave frequencies, the water surface oscillation coefficient is relatively small, while the pneumatic power remains at a large value, and the OWC device can effectively reduce wave loads in the direction of incoming waves. The optimal opening ratio of 1.51% may balance wave energy utilization efficiency with structural protection for the device.