岸礁地形上波浪增水和传递波的数值模拟研究

Numerical simulation of wave setup and transmitted wave over fringing reefs

利用完全非线性Boussinesq方程数值模型FUNWAVE-TVD,对珊瑚岸礁地形上波浪的传播变形进行了数值模拟。通过Demirbilek物理模型试验,测试了FUNWAVE-TVD关于岸礁地形上波浪传播变形的计算性能,并分析了模拟结果(包括波高、增水和爬高)之于空间网格步长、底摩阻系数和破碎阈值的敏感性。通过系列组次的数值模型试验,研究了岸礁地形上礁坪长度和礁后岸坡坡度对波浪增水、传递波波高和爬高的影响。结果显示:礁坪长度和礁后岸坡坡度的变化对礁坪增水的影响小;一定范围内,传递波高随礁坪长度的减小和岸坡坡度的增大而增大;爬高随礁坪长度的减小而增大,随岸坡坡度的增大先增大后减小。相关结果对礁顶工程建设具有一定的参考价值。

The fully nonlinear Boussinesq model FUNWAVE-TVD was used to simulate wave propagation and transformation over fringing reefs.Demirbilek′s experiments were selected to validate the numerical model,and the sensitivities of the numerical results(including wave height,wave setup and wave runup)to the grid size,bottom friction coefficient and breaking index were analyzed.Based on a series of numerical tests,the effects of reef flat length and beach slope on wave setup and transmitted wave height over the reef flat as well as the wave runup on the beach have been investigated.The results show that the changes of reef flat length and beach slope have little effect on wave setup over the reef.Transmitted wave height is found to increase with the decrease of the reef flat length and the increase of beach slope within certain range.Wave runup is found to increase with the decrease of reef flat length but increase first and then decrease with the increase of beach slope.The relevant results have certain reference value for engineering construction over fringing reefs.