Hydroelastic response of submerged wave energy devices

This study is concerned with hydroelastic interaction of water waves with a fully-submerged wave energy device. The oscillating component of the submerged energy device is a circular, horizontal disc. Wave interaction with the horizontal disc results in formation of time-dependent pressure differential above and below the disc, and consequently a periodic vertical force. The wave-induced force on the disc results in vertical oscillations of the horizontal disc. Rigid-body motion of the disc is restricted to vertical oscillations only by use of the guide rails that are attached to the main frame of the energy device, secured on the seafloor. The vertical oscillations of the disc is converted to electricity by use of a direct-drive power take off system. In this study, the effect of wave and structural conditions on the oscillations are studied. The disc may undergo some elastic deformation due to the wave loads, and this may effect the performance of the wave energy device. The hydroelastic deformations of the disc, and its effect on the oscillations is also considered by combining the three-dimensional linear potential theory with the structural finite element analysis. The wave-induced responses of the wave energy device, including oscillations, and structural deformations are presented for a range of wave frequencies, and results are compared with existing laboratory measurements. The elastic deformations are studied for the discs built of different materials and results are compared and discussed. The responses are analyzed for various PTO and control systems