Experimental Research On Wave Propagation Characteristics Under Reef Terrain

In recent years, there have been a lot of port hydraulic structures which are built on coral reef flat at home and abroad. The big wave propagating to the reef flat and the severe turbulence brought by wave breaking could cause serious local scour to buildings. But for the propagation characteristics about waves from the deep water to reef terrain and crossing the reef flat is still a lack of understanding. Quantitative analysis of wave height and wave energy attenuation and the criterion about wave breaking still have many differences.This paper first reviewed about the analysis and research of the propagation characteristics on wave in the depth of upheaval terrain, such as underwater shelf, ridge, submerged breakwater, and coral reef. The reef terrain is simplified to a1:5steep slope and a long horizontal reef flat section. Based on the simplified reef terrain, the physical experiments for the wave propagation process, criterion about wave breaking, the wave height and wave energy attenuation brought by wave breaking and changes of the wave spectrum for regular wave and irregular wave are carried out. Wave propagation process of the terrain are described and analyzed theoretically. Compared with the previous several wave breaking criteria the form and parameters of wave breaking criterion formula are given based on the test data. The empirical model which is used to describe wave height changes rule after breaking is verified with test data and the parameters with different depth have been given. The wave height and energy attenuation formulas are fitted out with the local water depth as indicators.The spectrum change and the relationship between wave height of each order and the incident wave height are studied.In this paper, a reef terrain wave breaking criterion is given, the wave height and wave energy attenuation formula as well as the spectrum of the crushing wave are analyzed preliminary. The research results could provide experimental data and reference to the practical engineering design and to numerical model on wave propagation in the depth of upheaval terrain.