| The integrated design of coastal structures and wave energy devices,with the advantage of cost and function sharing,can realize wave power and disaster prevention of Green Port near the coast or island.Coastal structures are mostly arranged in large-scale arrays,such as caisson and submerged breakwaters,and wave energy devices present the trend of higher efficiency,higher reliability,and clustering.The surrounding flow field typically is modified significantly by different types of wave resonance triggered by breakwaters layout,which affects the performance of wave energy devices arranged in an array.It is essential for the layout and application of devices to study the constructive or negative interaction between structure and wave energy device array.However,the interaction mechanism between breakwater and wave energy device array is still not fully understood,and there is a lack of efficient hydrodynamic analysis methods to evaluate composite structures array.Based on theoretical analysis and physical model test,wave resonance phenomena induced by caisson and submerged breakwater array and its influence on the hydrodynamic performance of wave energy buoy array is investigated.The hydrodynamic analysis method of hybrid coastal structure-wave energy buoy system is established,to explore the effect of wave resonance mechanism on wave energy capture of buoy array and wave attenuation of the breakwater.The interaction between coastal structure and wave energy device array is then examined in detail,which can provide a theoretical reference for the layout of the hybrid breakwater-wave energy device system and design specifications.The following works were carried out:(1)Aiming at wave resonance phenomena of caisson array,a semi-analytical model of wave interaction with caisson array is established.The relationship between trigger frequency of the total transmission,strong reflection phenomenon,and formation mechanism is explored.Based on experimental data,hydrodynamic coefficients and wave amplitude in wave chamber for different geometrical dimensions and wave factors are analysed.The influence of wave gathering performance of caisson array and flange reflection is investigated.It is found that the wave gathering effect of array caisson can effectively increase the wave amplitude in the wave chamber and can provide conditions for the placement of wave energy devices.(2)Given the wave gathering effect of array caisson,it is a way to arrange the wave energy device into the wave chamber.A solution to the generalized radiation problem of buoy array is proposed.A semi-analytical model of wave interaction with the integrated system of caisson array and wave energy devices is established,based on periodic boundary condition.The solution to generalized radiation problem is verified by Haskind relationship.The trigger condition of Rayleigh-Bloch wave involving diffracted and radiated waves are determined to derive reflection coefficient and transmission coefficient.The proposed semi-analytical model is validated by comparing experimental data.(3)The synergistic effect of wave gathering performance on the hydrodynamic efficiency of the device and the influence of energy capturing ability of the buoy on wave attenuation performance of breakwater are discussed.Hydrodynamic performance of the integrated system is investigated for geometrical parameters,involving the buoy locations,dimensions of caisson and buoy,and flange draft.The effect of wave resonance inside and outside the wave chamber on wave power extraction and attenuation performance of the integrated system is analysed.(4)Further investigation is carried out to explore the repressed effect of Rayleigh-Bloch wave on hydrodynamic efficiency and wave attenuation performance of the integrated system.The wave surface distribution characteristics of diffracted and radiated waves corresponding to Rayleigh-Bloch wave is analysed.The influence of incident angles,geometrical parameters,and PTO damping on hydrodynamic performance of the integrated system is investigated,to reveal the variation law of Rayleigh-Bloch wave and its interaction mechanism with wave focusing effect.(5)A multi-scale analysis method for Bragg scattering of submerged breakwater and buoy array is established,based on the asymptotic analysis method and Bloch theorem.The detuned wave envelope equation and bandgap width of Bragg resonance are solved.The multi-scale analysis method is verified by energy conservation law and comparison with the existing literature.The variation trend of reflection coefficient,relative amplitude and other parameters of the combination arrangement is deeply analysed inside or outside Bragg resonance bandgap.The repressed effect of Bragg resonance caused by submerged breakwater on the energy capture characteristics of buoy array is explored. |
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