The Study On Hydrodynamic Performance Of Oscillating Floater Buoy Wave Energy Converter

Facing the serious energy crisis, low carbon emission, energy conservation and thedevelopment of renewable energy will become the hotspot of the world’s energydevelopment. Among all kinds of new energy types, ocean renewable energy attractsmany countries’ concern, provided by the ocean which covers nearly71percent of theEarth’s surface. Wave energy has become one of the most promising types because ofits reserves and wide distribution.Nowadays, oscillating-body wave energy device consisting of the oscillating buoyand hydraulic system are classified as the third generation which has been developedrecently. Practical utilization has proposed urgent requirements for correspondingtheoritical reseasch including shape selection and power take-off (PTO) mechanism toimprove its performance.Based on potential flow theory, added mass and damping coefficient of cylindrical、conical floater are presented by solving related equations. Hydrodynamic equationsand corresponding boundary equations inducing PTO effects for buoy motion werefirst propsed in the present thesis. By solving above equations, effects of bouyweights, shape parameters on energy absorption spectrum bands, resonancefrequencies and relative amplitudes are investigated.In the experimental study, the relationship between the floater’s shape and peratingperformance is reflected by ascending and desending movement of floater. Effects ofwave conditions on oscillating velocities are also studied. Within test includingelectricity loads effects, the relationship between the floater’s output power andelectricity loads is also investigated.Base on Reynolds averaged N-S equation and VOF model, a3D numerical wavetank was established. Effects of incident wave and floater’s shape on its movementvelocity can be accurately simulated and verified by corresponding experimental data.The numerical model was successfully utilized for prototype device within PTO loads. Effects of the PTO loads on performance of wave energy devices are studiedunder different wave period.Considering the results of model tests and numerical simulations, the key shapeparameters of the device are proposed. The movement mechanism of floating buoywith PTO loads is also given in the thesis.