Response of U-Oscillating Water Column installed in a variable bathymetry region

The U-Oscillating Water Column (U-OWC) system is a wave energy harvester commonly embedded in vertical breakwaters and installed in intermediate water depths. It allows transforming a passive infrastructure (breakwater) into an active structure, by harvesting incoming wave energy while also creating a sheltered basin. The U-OWC is investigated in current literature via several tools. However, most of the models are developed assuming constant water depth in the region where the surrounding wave fields develop and propagate. This fact constrains their applicability to contexts in which the system is installed in bathymetry regions which are, at least, slowly varying in space. In order to overcome this limitation, in this work a BEM model is developed accounting for variable bathymetry effects, in conjunction with a nonlinear dynamic model of a U-OWC. The model supports calculation of hydrodynamic quantities involved in the dynamical system which are used for computing the U-OWC response and energy-wise performance. The proposed models are employed for quantifying the effect of the water depth variability on the converter response and on the energy converted by the system.