Hydrodynamic analysis of three-unit arrays of floating annular oscillating-water-column wave energy converters

This paper deals with the hydrodynamic analysis of an array of Oscillating Water Column (OWC) devices, made up of coaxial cylinders, which are floating either independently or as a unit forming a floating platform. The platform is considered either free - floating or as TLP configuration connected to the sea bottom. Numerical results concerning the three boundary value problems, namely, the diffraction, the motion - and the pressure - dependent radiation ones are given. They have been obtained through an analytical solution method using matched axisymmetric eigenfunction expansion formulations. In all cases the interaction phenomena with neighbouring bodies have been taken properly into account using the physical idea of multiple scattering. Numerical results for the first - and the mean second - order wave forces, the hydrodynamic interaction coefficients along with pressure hydrodynamic parameters, inner air pressure and free-surface oscillation amplitude inside and outside of each device are parametrically evaluated and supplemented by experimental data.