On the turbine-induced damping in Oscillating Water Column wave energy converter

The present paper deals with a study of the damping induced by a turbine in the power take off of an small scale Oscillating Water Column Wave Energy Converter. In order to study the turbine-induced damping, an experimental setup was built. The experimental setup consists of a wave flume 2000 mm long, 190 mm high and 96 mm wide with an impermeable beach as a dissipative system at the end to avoid wave reflections. The system is all built in Plexiglas to allow optical real-time observation. An Oscillating Water Column chamber model was placed in the measurement area between the wave-maker and the dissipative beach. The chamber was 37 mm long, 200 mm high and 96 mm wide also built in Plexiglas. In order to study the effect of turbine-induced damping on the system, a calibrated and variable hole was used to simulate the turbine presence, while outflow and inflow air velocity were measured by means of Particle Image Velocimetry (PIV) method. Pressures and velocities of air and water as well as the free water surfaces evolution were measured at different wave frequencies and heights.