风对聚焦波海堤越浪特性影响的数值模拟研究

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

在一些恶劣的海洋环境中,极端波浪与向岸风之间存在复杂的相互作用,严重威胁沿海设施的安全。本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聚焦波海堤越浪特性的影响,并重点讨论了向岸风风速、有效波高以及堤顶超高等因素对聚焦波海堤越浪水动力过程的影响机制。结果表明,随着向岸风风速、有效波高的增大以及堤顶超高的减小,聚焦波在斜坡式海堤上的最大越浪量、最大爬高、海堤的最大荷载以及沿程最大水位逐渐增大。向岸风会影响聚焦波的传播演变,增大聚焦波的波陡和传播速度,使波浪的破碎时刻和破碎位置提前,聚焦波高速流动的水体区域也明显增大,相比无风情况,其最大越浪量、最大爬高、最大水动力荷载以及沿程最大水位均有所增大。本文研究结果可为极端波浪的防灾减灾以及海岸防护工程的设计提供一定的参考。

In some harsh ocean environments,there are complex interactions between extreme waves and onshore winds that seriously threaten the safety of coastal facilities.Based on two-dimensional incompressible two-phase flow numerical model,this paper systematically studied the influences of onshore wind on overtopping characteristics of coastal seawall under focused wave,and focused on the mechanism of influences of onshore wind speed,significant wave height,and crest freeboards on overtopping hydrodynamic process of coastal seawall under focused wave.The research results show that,with the increase of onshore wind speeds,significant wave heights,and the decrease of crest freeboards,the maximum overtopping volume,maximum runup height,maximum hydrodynamic forces exerted at the coastal seawall,and spatial distributions of the maximum water elevation gradually increase.Onshore winds can affect the propagation and evolution of focused waves,increase the wave steepness and the propagation speed of focused waves,and cause the moment and position of wave breaking to advance.The high-speed flow area of focused waves also significantly increases.Compared with the no-wind condition,the maximum wave overtopping volume,maximum runup height,maximum hydrodynamic forces and spatial distributions of the maximum water elevation are increased under onshore winds.The research results of this paper can provide corresponding reference for the prevention and reduction of extreme waves and the design of coastal protection engineering.