Experimental Study On Wave Dissipation Coefficient For Semi-submersible Permeable Tetrahedron

In recent years climate change leads to the rising sea levels,more frequent bad weather on the ocean and recession of a shoreline.The port is impacted by waves becoming more and more severe.Therefore,the protection of the coast is particularly important,and all kinds of wave breaking structures have been applied to practical engineering.The traditional breakwater stands out above the sea,affecting the aesthetic.Floating breakwater can cover shortwave reasonably,but the transmittance of the long wave was still high.The use of semi-submersible breakwater has less demand for seabed geological conditions,and experiments find semi-submersible structure is more appropriately for the deep water;it allows water free to exchange and it has little effect on the surrounding environment.This paper proposes one kind of new structure based on the research of predecessors,called semi-submersible permeable tetrahedrons.The design theory of this model is that the structure is dived below sea level without destroying the natural beauty,and then study the wave dissipating effect of the structure when it is below sea level.Through physical model test,the effect of wave period,wave height,model width,the number of row,row spacing,draught and re-bar submerged depth on the transmission coefficient is studied,and get the results of different factor’s influence to the transmission coefficient.In this paper,the transmission coefficient of the incident wave under different conditions is got through the experiment of the physical model,which will be used to study the wave attenuation performance of semi-submersible permeable tetrahedrons.The results show that wave period has a significant impact on the wave attenuation performance of the model,and as the wave period increases,the wave attenuation performance of model gets worse;increased row number can increase its usefulness in the wave attenuation performance;as the row distance increases,the effect of wave attenuation gets worse;the transmission coefficient of model rises sharply and wave-breaking effect is very poor when the draught overs 0.1m;the wave attenuation performance gets worse when the re-bar submerged depth increases,and the elements swing drastically,that affects the stability of model.In conclusion,semi-submersible permeable tetrahedrons has the research value.Nevertheless it also needs correcting in the theories.