Experimental and numerical study of a two-body heaving wave energy converter with different power take-off models

Wave energy is one of the most difficult energies to be captured among marine renewables. With the technical progress, wave energy converters (WECs) are being tested in relatively deeper waters, which makes floating concepts almost the only choice. In this paper, a two-body heaving WEC where the wave energy is absorbed through the relative motion between the outer annular and the inner cylindrical buoys is studied. Both experimental and numerical studies are adopted for regular wave conditions. In the physical model test, a hydraulic system is used to achieve constant power take-off (PTO) damping force. Numerical simulations, validated against experimental data, are applied using both the frequency domain and the time domains analyses. Different types of PTOs, including constant, linear and nonlinear damping forces, are undertaken to evaluate the hydrodynamic and power absorption performance of such device.