Sequential optimization of the geometrical parameters of an OWC device based on the specific wave characteristics

Abstract

Conventional Wave Energy Converters (WECs) are designed to extract the wave energy from the oceans with the wave power of 20–50 kW-per-meter. If these WECs are used where the wave energy is less than the mentioned values they cannot work in their maximum performance. Therefore it is proposed to optimize the WECs for the average wave power in each place. In this research, an Oscillating Water Column (OWC) is investigated to extract the maximum output power based on the characteristics of the Faroor island waves in the Persian Gulf. The average power of the Persian Gulf Waves is less than 10 kW-per-meter and using a conventional wave energy converter is not efficient. Numerical simulation is performed using ANSYS-Fluent software. In this study, waves are generated using nonlinear second order stokes theory. Also, the k- ω turbulence model and volume of fluid scheme are used for turbulence modeling and interface tracking respectively. Finally, with optimizing each parameter an optimum geometry with an efficiency of 41.5% is obtained to extract the Faroor Island waves’ energy. This study emphasizes on this fact that one should design a new geometry to reach the best performance of the OWC in new wave characteristics. • The optimized OWC dimensionless parameters change with wave characteristics. • The optimized OWC increases the efficiency from 19.75% to 41.5%. • The bottom step can increase the hydrodynamic efficiency of the OWC. • The best length of the bottom step is equal to one wavelength. • The best front angle of the bottom step is 90 degrees.