摘要:防波堤对防御波浪对港域的侵袭，保证港口具有平稳的水域以便船舶停靠系泊，顺利进行货物装卸工作和上下乘客起着重要的作用。中国是一个海洋大国，其海岸线共计长达3.2余万公里，其上分布着大大小小的港口，因此研究波浪与防波堤的相互作用对于经济发展和保证港口安全都具有重要意义。

水下淹没平板，作为防波堤的一种，可以有效地减小波浪反射系数和透射系数。与传统的固定式防波堤相比，板式防波堤具有以下优势：很强的地形适应能力；便于水体交换，满足环境保护的要求；工程造价相较于其他形式的防波堤较低，施工方便。另一方面，网衣是一种多孔的、复杂的柔性结构物，其对波浪的传播具有一定的削弱作用。而且其取材方便，既满足经济发展的要求，同时又满足环境保护的要求。目前为止国内外对于板—网衣式防波堤的研究还相对较少。

本文基于计算流体力学理论建立二维数值波浪水槽，来模拟波浪与单板、双板以及双板—网衣式防波堤的相互作用，并对其消浪性能进行研究。对瞬时自由表面流体质点采用VOF（VolumeofFluid）法进行追踪，对压力—速度耦合方式选用PISO算法（算子分裂压力隐式算法）。同时采用两点法分离水平板迎浪侧的入射波浪和反射波浪，得出反射系数；通过监测点的数据得出透射波高从而计算出透射系数。

论文的主要内容分为五章：第一章是绪论，简要介绍了课题的研究背景、研究目的以及与该课题相关的国内外的研究进展。第二章介绍了建立数值波浪水槽的相关数学方法，包括控制方程、边界条件、造消波理论、网格划分以及多孔介质模型与网衣相互转化的原理。第三章对相关的数值模型进行验证：首先对数值水槽的造消波效果进行验证，然后对波浪与淹没式结构物相互作用的模型进行验证，最后对网衣模型进行了验证。第四章探究了波浪与双层板式防波堤的相互作用，并以单板为对照，研究了双板间隙、波高以及板长等参数对双层板式防波堤的消浪性能的影响。第五章根据上一章得出的结论进一步研究波浪与双板—网衣式防波堤的相互作用，并探究了网衣高度、网衣数目等参数对其消浪性能的影响。

关键词：数值波浪水槽；淹没水平薄板；多孔介质模型；两点法；板—网结构

Abstract:Breakwaters are commonly used to protect engineering structures and ships in the harbor against waves. China is a large ocean country with the total coastline of more   than

3.2 million kilometers, along which there are many ports. Therefore, the study of the interaction between wave and breakwater becomes one of the key technology of harbor economic development and construction safety.

Submerged horizontal plate can be applied as an eco-friendly breakwater with low transmission and reflection coefficients. When compared with traditional breakwaters,the attractive merits of the plate breakwater include less dependent on  seabed condition, waters exchanging freely and most importantly inexpensive in construction. As for the net cage, it is a porous and complex flexible structure, which can weaken the wave. In addition, the net meets both the requirement of ecnomic development and the requirement of environmental protection. So far at home and abroad, the question about the interaction of wave and plate-net breakwater has not been studied.

Based on the computational fluid dynamics (CFD) theory, a two-dimensional numerical wave flume is established to simulate the interaction between wave and plate-net breakwater, and the wave-absorption performance of plate-net breakwater is studied. The VOF method is used to track the instantaneous free surface fluid mass, and the PISO algorithm (operator splitting pressure implicit algorithm) is selected as the pressure-velocity coupling method. At the same time, the two-point method is used to separate the incident wave and the reflected wave on the wave side, and the reflection coefficient is obtained. The transmission wave height is obtained by the data of the monitoring point and then calculate the transmission coefficient.