中文摘要：

波浪聚焦被认为是产生极限波浪的重要机理之一，近年来受到普遍重视。通过高阶谱方法，引入造波边界建立数值计算模型，模拟聚焦波浪在不同方向分布时的产生和聚焦过程，研究波浪的方向分布对聚焦波浪的波面、波峰最大值、聚焦点的偏移、波面参数及频谱的影响。研究结果表明波浪方向分布越窄，波浪的非线性影响越强、波面越陡，波峰值、聚焦点的偏移和波面特征参数都越大；同时方向分布对波浪聚焦前后的能量具有很大的影响。

英文摘要：

Three-dimensional （3D） directional wave focusing is one of the mechanisms that contribute to the generation of extreme waves. Recently, researchers pay more attention to the focusing wave. In this paper, a numerical model based on the High Order spectral （HOS） method is developed. In the developed numerical model, the wave maker boundary condition is introduced to simulate the wave generation. The directional focusing wave genomtion and focusing propagation are calculated using the numerical method. The effects of directional spreading on wave surface elevation, the maximum crest, shift of focusing points, surface parameters and frequency spectra are studied. The results show that when the directional spreading becomes narrower, the focusing wave surface elevations become steeper, the maximum crest, the shift of focusing point and surface parameters become bigger, and the change of spectra becomes evident. ＂lifts implies that the nonlinearity between focusing wave components becomes stronger with narrow directional spreading.