Overtopping Wave Energy Convertor (OWEC) is an offshore wave energy convertor, which comprises the circular ramp and reservoir. It collects the overtopped waves and converting water pressure head into electric power through the hydro-turbines installed in the vertical duct, which is fixed in the sea bed. The performance of OWEC can be represented by the operating water heads of the device, which depends on the amount of the wave water overtopping into the reservoir. In the present paper, the reservoir with the duct connecting to the sea water are studied in the 3D numerical wave tank, which has been developed based on the computational fluid dynamics software Fluent 6.3. Both the overtopping motion and the discharges of the reservoir are investigated together, and several shape parameters and incident wave conditions are varied to demonstrate their effects on the performance of OWEC.
The generation of electric power utilizing clean and renewable ocean resources is one of the most important alternative energy technologies for overcoming shortages in energy resources caused by excessive use of fossil fuels. Among various ocean resources, wave energy is the most abundantly available and applicable in most coastal and offshore areas. Due to the advantages of simple converting technique and producing cost over other types of ocean energy, the wave energy conversion system is feasible to be established for the commercial power production. Plenty of wave energy absorption devices have been invented, and several of them have been utilized in the electricity generation. Recently, the Oscillating Water Column (OWC) type has been widely employed in the application for the wave energy conversion. The disadvantage of this device is the low wave energy converting efficiency. Overtopping Wave Energy Convertor (OWEC) has the sloping walls and reservoirs to lift waves to the levels above the average surrounding ocean.