Study of the turbine power output of an oscillating water column device by using a hydrodynamic - Aerodynamic coupled model

The availability of clean energy of wind waves is enough to meet current demand of the world, attracting researches to find devices with good performance to extract this type of energy. The oscillating water column converter is a type of device that has been extensively studied for this purpose. This paper describes a numerical analysis of an onshore oscillating water column device taking into account hydrodynamic and aerodynamic coupling, performance curves of the turbine and air pressure control by a relief valve. The numerical analyses are carried out by the Fluinco model, based on slightly compressible flow method to solve the Navier-Stokes equations, and employing the two-step semi-implicit Taylor-Galerkin method. The aerodynamic model is based on the first law of thermodynamics applied to the air column inside the chamber and on turbines similar to Pico's. The turbine power output with air pressure control inside the chamber due to a relief valve is compared to the one without control. A significant increase in the power output by using the pressure control in comparison with that without control is observed. The analysis of the turbine power output considers different turbine diameters and ranges of rotational speeds.