Study On Hydrodynamic Characteristics Of Integrated System Of Wave Energy Converter And Floating Breakwater

Oscillating buoy wave energy converter(WEC)is highly effective,but the high costs of research and construction seriously impede its development.At the same time,floating breakwater simply dissipates wave energy by reflection and is subject to large environmental stress loads due to the high wave energy density.WEC also has the function to dissipate wave energy,which is similar to breakwater,but by absorption.If an array of WECs are deployed in front of a breakwater,they can protect it from environmental loads.Therefore,the integration of floating breakwaters and oscillating buoy WECs can reduce the research cost and protect the breakwater.First,based on the potential flow theory,a time-domain numerical model is developed using higher-order boundary element method(HOBEM).Then,a CFD numerical model is established based on viscous Computational Fluid Dynamic(CFD)theory and Star-CCM commercial software.The convergence of the time and space steps and the accuracy of these two models are verified,which guarantee the rationality of the numerical models used in this paper.At the same time,the calculation results of the two numerical models and are compared with the published experimental results to investigate the influence of viscous on the results,which determines the adoption of the CFD numerical model in the following investigation.Then,the factors effecting the wave attenuation and wave energy extraction performance of the integrated device,including the floater bottom shape,the floater width,the proportion of underwater parts of floater,and the height of the floater bottom baffle,are investigated by the established numerical models.A novel integrated device with new floater shape is proposed by simulation,which has good wave attenuation and energy extraction performance.According to the results of the research,the performance of the integrated device can be improved by optimizing the geometric parameters of the device.Finally,based on the research of the single body integration device,a double floaters hybrid system consisting of a WEC and a fixed box-type breakwater is proposed.The hydrodynamic performance of the double floater integrated device is compared with those of the single body integration device.In addition,the effects of floater shape,the ratio of floater draught,the ratio of floater width,and the space between floaters on the hydrodynamic performance of the double floater hybrid device are investigated.