风作用下规则波在岸礁地形上的水动力特性数值研究

Numerical Study on Hydrodynamic Characteristics of the Regular Waves on Fringing Reefs Under Wind Forcing

基于气液两相流模型建立二维数值风浪水槽,采用VOF(Volume of Fluid)模型捕捉自由液面,研究了风作用下规则波在岸礁地形上的水动力特性。将计算结果与实验数据对比,证明了该模型计算风作用下波浪传播的准确性,并进一步分析了不同风速对规则波在岸礁地形上水动力特性影响。结果表明:有风作用时,破碎区的波峰高于无风作用时,冲泻区的波峰低于无风作用时,在风速0~8 m/s范围内,风的作用不会改变波浪在岸礁地形上的破碎类型,但会导致波浪提前破碎并影响破碎波形态变化过程。风的作用会改变波浪在岸礁地形上传播时各断面水平时均流速沿水深分布结构,并且会导致水气交界面附近水质点的速度增大,影响范围随着风速的增大而增大。

Based on the two-phase flow model,a two-dimensional numerical wind-wave tank was established.The VOF model was used to capture the free surface,and the hydrodynamic characteristics of regular waves on fringing reefs under wind forcing were studied.Comparing the numerical simulations with the experimental data,it shows that the two-phase flow model is accurate in simulating waves transformation under wind foring.The influence wind speed on the regular wave transformation on the reef is further analyzed.The results show that the wave crest in the surf zone under wind forcing is higher than that without wind forcing,and the wave crest in the swash zone under wind forcing is lower than that without wind forcing.In the range of wind speed from 0 to 8 m/s,the effect of wind will not influence the wave breaking type,but result in earlier wave breaking and affect the morphology change process of breaking waves.The wind can change the distribution structure of the time-averaged velocity along the topography when waves propagate on fringing reefs,and can increase water particle velocity near water-air interface,and the influence range also increases as wind speed increases.