非线性特征伴随了波浪从浅水变形到破碎的整个过程，对近岸波况变化、泥沙输运、波浪破碎等现象都起到至关重要的作用，一直是海岸工程研究的热点问题之一。目前，对非线性波浪的研究主要针对单向波浪在二维空间内的简单海岸地形上的传播，这显然难以全面反映真实海浪在三维空间内与复杂海岸地形之间的相互作用。本项目拟开展数值模拟试验，围绕“三维复杂海岸地形条件下的波浪非线性特征”这一核心问题，结合入射波况和海岸地形变化的影响，对具有多向分布特征的波浪在常见的沙坝海岸以及珊瑚礁海岸地形条件下的非线性特征开展研究。从三维空间内的非线性相互作用探讨近岸波浪非线性特征的诱发机理，分析岸底地形和深水波况对波浪非线性特征的影响，揭示复杂海岸地形下的波浪非线性特征分布规律。以期通过该项目的开展，加深对近岸非线性波浪的本质认识，得到更符合真实海洋环境下的科学结论，并为该类海岸条件下开展的工程建设提供理论依据。

The nonlinear characteristics of waves, throughout the wave deformation to wave breaking process, play a crucial role in the evolution of wave condition, sediment transport and breaking, and have been a hot issue in coastal engineering research. Recent studies of wave nonlinearity have mainly focused on the transformation of unidirectional waves on a simple coastal topography in two dimensions (2D), which is evidently cannot accurately reflect the interactions between real ocean waves and complex coastal topographies in three dimensions (3D). In this project, we will conduct a numerical experiment to investigate the nonlinear characteristics of ocean waves on a 3D complex coastal topography. By considering the influences of wave condition and coastal topography, the nonlinear characteristics of multidirectional waves on typical sandbar and coral reef coasts are investigated. The generation mechanism of nonlinear features for coastal waves will be investigated through nonlinear interactions in three dimensions (3D), and the effect of bottom topography, as well as the deep water conditions to the nonlinear features will be examined. The distributions of wave nonlinearities for some specific coastal topography will be derived. The results of this study will improve the understanding of nonlinear waves, from which we can draw conclusions that are more consistent with the real marine environment. This work can also provide some theoretical basis for engineering constructions in such coastal conditions.