风对孤立波海堤越浪特性影响的数值模拟研究

Numerical simulation study on influences of onshore wind on overtopping characteristics of solitary wave under coastal seawall

海堤在保护沿海城镇免受极端波浪破坏方面具有重要作用。该文基于二维不可压缩两相流数值模型,系统研究了向岸风对孤立波海堤越浪特性的影响。通过数值计算结果与实验数据的对比,验证了该数值模型的可靠性,并重点讨论了向岸风风速、入射波高、堤顶超高、岸滩坡度和海堤坡度等因素对孤立波海堤越浪水动力过程的影响。研究表明:随着向岸风风速、入射波高的增大以及堤顶超高的减小,孤立波的最大越浪量、最大爬高以及沿程最大水位高程逐渐增大;随着岸滩坡度和海堤坡度的增大,孤立波的最大越浪量分别增大和减小,最大爬高逐渐增大。向岸风会影响孤立波海堤越浪的水动力特性,增大孤立波的波陡以及波峰传播速度,使波浪提前破碎;相比无风情况,最大越浪量、最大爬高、最大水动力荷载以及沿程最大水位高程均有所增大。研究结果可为海岸工程的设计提供参考。

Seawalls play an important role in protecting coastal towns from extreme waves damage.Based on two-dimensional incompressible two-phase flow numerical model,the influences of onshore wind on overtopping characteristics of solitary wave under coastal seawall were systematically studied in this paper.The reliability of the numerical model was verified by comparing the numerical results with experimental data,and the influencing factors such as onshore wind speed,incident wave height,crest freeboards of the coastal seawall,beach slope and seawall slope on the hydrodynamic process of solitary wave overtopping of coastal seawalls were discussed in detail.The research results show that with the increase of onshore wind speed,incident wave height and the decrease of crest freeboards of the coastal seawall,the maximum overtopping volume,maximum runup height and spatial distributions of the maximum water elevation gradually increase.With the increase of beach slope and seawall slope,the maximum overtopping volume increase and decrease,respectively,while the maximum runup height gradually increase.Onshore wind can affect the hydrodynamic characteristics of solitary wave overtopping of coastal seawall,increase the wave steepness and the wave crest propagation speed and cause the wave breaking earlier.Compared with the windless condition,the maximum wave overtopping volume,maximum runup height,maximum hydrodynamic forces and spatial distributions of the maximum water elevation are increased under onshore wind.The results of this study can provide a reference for the design of coastal engineering.