大糙率礁面影响下珊瑚礁海岸附近规则波演化及爬高试验研究

A FLUME STUDY OF REGULAR WAVE TRANSFORMATION AND RUN-UP AROUND REEF COASTS WITH LARGE SURFACE ROUGHNESS

本文通过波浪水槽试验研究了大糙率礁面影响下波浪沿礁的演化和爬高规律,测试了一系列规则波工况并对比了光滑礁面和粗糙礁面的情况。结果分析表明:二次谐波是礁坪上透射波的重要组成成分,粗糙礁面使主频波和二次谐波减小,对更高阶波的影响不显著;相对礁坪水深是描述礁坪上波浪透射的关键参数,礁面从光滑变为粗糙时海岸附近透射系数显著减小,能量衰减系数平均增大了8%,但礁前反射系数与礁面糙率之间无明显关系;礁后岸滩爬高随着透射波高的增大而增长,最后拟合了本文试验条件下珊瑚礁大糙率礁面预测规则波爬高的关系式。

To investigate the regular wave transformation and run-up across reef profile under the effect of reef surface roughness,a series of laboratory experiments were carried out in a wave flume,and both the smooth and the rough reef surfaces were tested.The results show that the 2nd harmonic waves are important components of transmitted waves on reef flat.The rough reef surface damps the 1st and the 2nd harmonics,and its impact on the higher harmonics is insignificant.The relative reef-flat submergence is a key parameter to describe the wave transmission.Wave transmission coefficient dropped significantly but energy dissipation coefficient increased by 8%on average in all scenarios when reef surface became rough.However,wave reflection from the reef seemed independent of surface roughness.Wave run-up on the back-reef beach increased with the increasing transmitted wave height.Finally,an empirical formula was proposed with which regular wave run-up on the back-reef beach could be predicted in large surface roughness in the tested scenarios.