岸礁礁冠对波浪传播变形及增水影响的实验研究

摘要

To understand the role of reef crest in wave transformation and wave-induced setup over fringing reef, a series of experiments were carried out in a wave flume using idealized models that simulate a field fringing reef with the presence of a reef crest. Experimental results were reported for four water depths and for a variety of regular wave conditions. Preliminary analysis showed that the presence of the reef crest significantly alters the wave transformation process near the reef edge, especially the intensity of wave breaking and the generation of high harmonic waves. Wave setup was found to increase with the increase of incident wave height and wave period, but decrease with the increase of water depth. The reef crest controls the water level above the reef flat in a way similar to that a submerged breakwater controls the water level on the leeside of the breakwater; wave setup over a reef flat with a crest is generally much larger than that without; and a new dimensionless parameter to analyze the wave setup is introduced in order to take the crest configuration into consideration.%通过在波浪槽中进行一系列物理模型实验来研究珊瑚岸礁礁冠的存在对波浪传播变形和礁坪上增水的影响，实验在现场观测的基础上采用了理想化的岸礁和礁冠模型，并测试了4种礁坪水深和不同的入射波工况。实验结果表明，礁冠能显著改变波浪在礁坪边缘的传播变形过程，尤其是波浪破碎强度和高频波的产生；礁坪的增水随着入射波高和周期增加而增加，随着水深的增加而减少；礁冠的阻水效应类似于潜堤，对于其后礁坪上增水的大小起决定作用，礁冠存在时波浪增水显著增大；随后引入了一个新的无量纲参数来考虑礁冠的存在对增水的影响。