岛礁地形影响下多道浮式防波堤耦合水动力分析方法及消波机理研究

With the increasing requirements of the marine resource exploitation of the reefs in South China Sea, more in-depth researches of floating breakwaters need to be completed as it provides protection to floating structure in the construction process. At present, floating breakwaters have good effect on attenuating of the short period wave, but the transmission coefficient of long period wave is still high. In order to dissipate the long period wave in the South China Sea, multiple-row floating breakwaters were designed to attenuate the incident wave. However, many problems are still need to be solved as follow: (1) the wave characteristics may change due to the effect of the reefs; (2) the hydrodynamic problem of multiple-row floating breakwaters belonging to multi-body system is not easy to be investigated; (3) Wave attenuation is affected due to the free surface between multiple-row floating breakwaters. Based on the fluid-structure interaction dynamic, coupled hydrodynamic model of multiple-row floating breakwaters with mooring system is established near reefs and the model is solved by SPH, meanwhile, model experiment is conducted to verify the correctness of numerical model. Also, how the distance between breakwaters affect the free surface resonance properties and wave attenuation mechanism of multiple-row floating breakwaters are explored. Finally, the hydrodynamic coupling characteristics and wave evolution law of multiple-row floating breakwaters near reefs are revealed. The research results of this project will provide theoretical and technical support for further research of floating breakwaters.

随着我国南海岛礁建设及资源开发需求的日益迫切，浮式防波堤作为保护岛礁建设过程中浮式结构物安全的海上设施，具有重要的研究价值。当前浮式防波堤对短周期波浪消波效果较好，对长周期波浪透射系数仍然较高。为消除我国南海长周期波浪，本项目拟布置多道浮式防波堤联合消波，其水动力性能分析还面临如下挑战：（1）受岛礁地形的影响，波浪特征发生改变；（2）多道浮式防波堤属于多系统耦合水动力问题，求解较为困难；（3）多道浮式防波堤之间自由液面的运动极为复杂，影响消波效果。本研究考虑岛礁地形的影响，基于流固耦合动力学理论，建立多道浮式防波堤与系泊系统耦合动力学模型，通过SPH方法求解该数值模型，采用模型实验验证数值方法的正确性，探究多道浮式防波堤距离对浮体间自由液面共振规律的影响及多道浮式防波堤的消波机理，揭示岛礁地形影响下多道浮式防波堤耦合水动力特性及波浪演化规律，为岛礁浮式防波堤的研究提供理论依据和技术支撑。

当前浮式防波堤对短周期波浪消波效果较好，对长周期波浪透射系数仍然较高。为消除长周期波浪，本项目布置多道浮式防波堤联合消波，考虑岛礁地形的影响，建立多道浮式防波堤与系泊系统耦合动力学模型，探究多道浮式防波堤间自由液面共振规律及消波机理，揭示岛礁地形影响下多道浮式防波堤耦合水动力特性及波浪演化规律。主要完成的研究内容如下：1）基于粘性理论，建立改进的SPH波浪数值模拟方法，提升SPH方法的计算精度，同时结合岛礁地形分布特点，建立岛礁地形影响下波浪传播的数值模型；2）基于集中质量方法，实现动态锚链的模拟，建立波浪与浮式防波堤、浮式防波堤与系泊系统全时域多道耦合SPH数值模型，并编写计算程序；3）分析浮式防波堤系统之间的间距、不同入射波参数等条件下多道浮式防波堤运动响应、波浪透射特性以及消波机理，得到波浪演化规律；4）在多道耦合分析方法的基础上，建立岛礁地形影响下多道浮式防波堤多系统耦合水动力分析方法，得到岛礁地形条件下多道浮式防波堤水动力及波浪的透射特性；5）开展岛礁地形影响下浮式防波堤与系泊系统耦合水动力模型实验，测量多浮体的运动响应、系泊系统的张力和防波堤模型之间以及堤后波浪历程等参数，获得多道浮式防波堤波浪演变规律，数值模拟结果与模型试验误差小于15%。在该项目的资助下，发表论文20篇，其中SCI论文16篇、EI论文1篇、核心论文3篇；授权发明专利11项（国际发明专利4项、中国专利7项），出版学术专著1部，项目的研究成果可为我国海洋资源开发以及岛礁建设的研究提供理论依据和技术支撑。