Investigating the influence of geometry on the performance of a wave-powered marine observation buoy: The wave-to-wire approach

As an important marine monitoring platform, marine observation buoys have been widely used in marine environmental monitoring, marine resource surveys, etc., attracting great attention worldwide. However, the lack of a reliable power supply is a crucial problem that seriously restricts buoys’ operation lifetime and carrying capacity. The floating buoy with an inbuilt wave energy harvester is a promising solution to the long-term and sustainable energy supply problem. This study develops a fully coupled wave-to-wire (W2W) mathematical model where the relevant friction parameters and power-take-off system parameters are identified from flume experimental results. Besides, the influence of geometry on the buoy’s electric power performance is investigated under regular and irregular waves, respectively. Numerical results imply that the cylinder-cone-shape buoy produces the most electric power when the three shapes have the same geometric sizes, while the cylinder-sphere-shape buoy performs the best W2W efficiency among the three shapes with the same mass. Moreover, a high W2W efficiency of up to 23.13% is gained under a regular wave. Finally, according to the similarity theory, the averaged electric power of a full-size buoy is estimated at 4.84kW in realistic sea states.