Structual Design And Optimization Study Of The Breakwater Integrating WECs Under Irregular Waves

With the development of the national economy,the rapid increase in population and the improvement of living standard,the fast growing demand for energy has become the focus of global concern.As the traditional energy sources will be depleted soon,it is imperative to develop and utilise clean,economical renewable energy.Wave energy,which is renewable and clean,has received extensive attention from scholars at home and abroad in recent years.The breakwater with the wave power generation function comprehensively combines the advantages of the perforated caisson breakwater and the OWC wave energy conversion plant.While maintaining the water stability and protecting the port area against waves,it can also generate power from wave energy,in which way the renewable energy is utilised,and energy shortage problem would be alleviated effectively.Based on the 'Shore-based Energy Island Innovation Project',this paper carries out the design and experimental study of CU-OWC&CB structure under the action of irregular waves.Firstly,the physical model test was carried out according to the preliminary design results of the structure,and the variation law of the wave force before the breakwater under the action of irregular waves and its influencing factors were explored.Secondly,the structural stability of the wave power generation breakwater under typical conditions and extreme conditions was calculated and analysed.Finally,based on the wave force and its distribution characteristics of the experimental model,the finite element numerical simulation model was established in finite element analysis software,and the stress-strain distribution characteristics of the chamber was explored to complete the optimal design of the structure size.The specific research contents are as follows:(1)Based on STAR-CCM+,the three-dimensional numerical wave flume model was established,by which the optimal inclination angle of the wave energy conversion plant was determined under given conditions.The preliminary design study of structural geometry was carried out,and the overall stability of the structure was verified according to the theoretical formula.(2)The physical model experiment under irregular waves was carried out,where the irregular wave elements were simulated and test procedures were clarified.The time-course variation curves of the wave pressure in each monitoring point was obtained.The relationship between the incident wave period,wave height,working water level,vent hole size influencing factors and wave pressure was explored.(3)Based on the physical model test results,the wave force obtained from the theoretical calculation,the regular wave and irregular wave tests were compared and analysed,and the wave force change trend was studied.The causes of wave force changes in the front of the breakwater were analysed,and the study of structural stability under irregular wave force was finished.(4)Based on ANSYS,the finite element numerical analysis model under the irregular wave load was established,the structural static response analysis was carried out to investigate the stress and strain distribution on the outer wall and bottom of the chamber.The preliminary design of the structure has a large optimization space,thus the size of the caisson and the height of the filling were optimized.Based on the numerical simulation results,the optimal filling height was determined,and the overall stability calculation of the structure was completed.