非淹没刚性植被影响下孤立波在岸滩上的爬高

Solitary wave run-up on beach slopes influenced by unsubmerged rigid vegetation

为探究海岸刚性植被对海啸波的削弱效应,通过物理模型试验和数值模拟研究了孤立波与不同坡度岸滩上非淹没刚性植被的相互作用问题。物理模型试验在波浪槽中进行,测试了不同的入射波波高、植被密度和岸滩坡度对孤立波爬高的影响,并运用物理模型试验数据校核改进后的Boussinesq方程,得到植被的拖曳力系数。结果表明:拖曳力系数随植被密度的增大而增大,随坡度增大而减小;植被后的无量纲透射波高和无量纲岸滩爬高随着无量纲的入射波高的增大而减小,随着植被密度的增大而减小;当岸滩坡度增大时,无量纲透射波高增大而无量纲爬高并无显著差异。最后根据回归分析得出了岸滩爬高与相对入射波高、植被密度和岸滩坡度的幂函数型经验关系式。

To investigate the mitigation of tsunami waves by coastal rigid vegetation,the interaction between a solitary wave and unsubmerged rigid vegetation on different beach slopes was studied by both laboratory experiments and numerical simulations.The laboratory experiments were conducted in a wave flume,and the effects of different incident wave heights,vegetation densities and beach slopes on the wave run-up were examined.Boussinesq equations were improved and validated by the experimental data,based on which the drag force coefficient of vegetation was obtained.The results show that the drag coefficient increases with the increase of vegetation density but decreases with the increase of beach slope.The dimensionless transmitted wave height behind the vegetation and the subsequent dimensionless run-up height on the slope decrease with both the increase of the dimensionless incident wave height and the vegetation density.When the beach slope is increased,the dimensionless transmitted wave height increases but the variation of the dimensionless run-up height is insignificant.Finally,an empirical power-law relation is obtained to predict the dimensionless wave run-up height through the dimensionless wave height,the vegetation density and the beach slope by regression analysis.