Analytical and experimental study on tandem WEC-type floating breakwaters

This is the author accepted manuscript. The final version is available from EWTEC via the link in this record.Tandem wave energy converter (WEC)-type floating breakwaters, which is expected to overcome the shortcomings of the single-pontoon system (i.e., the narrow effective frequency bandwidth for the effective transmission coefficient KT 20%), is proposed. The tandem-pontoon system consists of a pair of single-pontoon WEC-type floating breakwaters (details see Ref. [1]). An analytical method based on linear potential flow theory is adopted to predict the hydrodynamic performance of the singlepontoon and tandem WEC-type floating breakwaters, respectively. Analytical solution showed that the effective frequency bandwidth for the tandem-pontoon system is obviously broader than that for the single-pontoon case. Note that, economically, the volume of the tandem-pontoon system equals to that of the original single-pontoon system. Furthermore, to confirm the phenomenon of boarder effective frequency bandwidth found by analytical method, an experimental study is conducted to investigate the hydrodynamic performance of the WEC-type floating breakwater. The power take-off (PTO) system consisting of the magnetic powder brake, the current controller and the torque-power sensor is used to measure the produced power and the damping force. Experimental results also reveal that the tandem-pontoon system performs more effective than the single-pontoon system in terms of the effective frequency bandwidth.The authors would like to acknowledge the financial support of the National Natural Science Foundation of China (Grant Nos. 51379037 and 51679036) and the Royal Academy of Engineering under the UK-China Industry Academia Partnership Programme (Grant No.UK-CIAPP\73)