Numerical Simulation Of Wave Propagation And Field Characteristic On Coral Reefs With SPH Method

Coral reef coast is a natural breakwater. It's can effectively block the waves off the coast and storm surge on coastal erosion. With the development of ocean engineering construction, buildings have been built on the coral reef. But the topographic condition of the coral reef coast is different from the ordinary nearshore topographic condition. There is dramatic change of water level in front of the coral reef. Coral reef flat can be very wide, and the water depth above it is very shallow. Small waves can transmit through the reef flat without broken, but larger wave deformation and broken will occur in the process of wave propagation. So the height of the waves which can transmit through the reef flat is limited by the depth of the water above the reef flat. Wave propagation through the reef flat will interact with the buildings on the reef flat. So it is necessary to understand the waves propagation law and the motion law of water above the reef flat.In this paper,2-d numerical wave flume was established and the water wave propagation on different slope of reef flat was carried out which based on smooth Particle dynamics method and N-S hydrodynamic control equation. At the same time, the physical model of regular wave propagation on steep reef flat slope (1:1) was designed at water channel In Dalian university of technology in order to measure and analysis the wave surface change at different location and movement regularity of flow on reef flat. Based on the analysis of experimental data, wave propagation process was simulated on reef flat which changed from a steep slope (1:1) to the flat that had a depression on the roof. Wave surface and wave velocity of the numerical calculation results were in good agreement with physical model test data which declared that the established SPH numerical wave flume could simulate the deep wave propagation problem on steep reef flat.This paper summarizes the laws of wave deformation and field characteristic in the process of wave propagation over reef flat, and then analyzes the factors on the impact of these laws including the incident wave period and wave height, submerged depth of the reef flat, and the reef slope degree. Finally, this paper analyzes the variation of flow field on the coral reef flat through the velocity vector diagram.