| With the increasing strategic significance of the ocean,the interaction between waves and fringing coral reefs has become one of the main research focuses of nearshore hydrodynamics in recent decades.my country has established a series of artificial reclamation islands and reefs based on the South China Sea.These islands and reefs have poor survivability under the influence of the changing ocean weather.Based on the above research background,this paper uses the Dual SPHysics open source program to numerically simulate and analyze the propagation and deformation of different waves along the offshore islands and reefs,as well as the structure of the moored floating body and the hydrodynamic performance of different waves under the reef terrain.The following is the main work:（1）Study the propagation of irregular waves with different wave heights and different wave periods and solitary waves with different wave heights and different reef flat water depths along the coral reefs under ideal conditions,focusing on the analysis of the wave changes generated when different waves propagate on the reefs and the different Wave deformation at the wave monitoring point.The research shows that when irregular waves and solitary waves climb along the front slope of the reef,the wave heights will become larger due to shallowing.With the further propagation of the wave,wave breaking occurs at the reef edge,and the breaking wave presents a waveform with a steep front and a gentle back.When the breaking wave continues to propagate along the horizontal reef flat,the wave height tends to be flat due to the dissipation of wave energy.For irregular waves,the increase of water caused by wave breaking will cause the average water level on the reef flat to rise.The phenomenon of water increase caused by long-period waves and short-period waves is more obvious,and the average water level rise caused by the horizontal reef flat is higher,and the average water level rise caused by the large wave height condition and the smaller wave height condition is higher.For solitary waves,when the breaking wave propagates along the horizontal reef flat,the smaller the reef flat water depth is,the faster the dimensionless wave height Hi/H0decays,and with the increase of the incident wave height H,the breaking wave on the reef flat increases.The energy transmittance becomes smaller,and the faster the breaking wave energy dissipates.（2）The interaction between regular waves,irregular waves and solitary waves with different wave heights and wave periods and the mooring floating structure under the terrain of islands and reefs is studied and calculated and analyzed.The influence of different waves on the dynamic response characteristics of the mooring floating structure under the island reef terrain and the wave deformation when the wave continues to propagate along the island reef terrain after wave elimination by the floating structure is analyzed.The research shows that when a mooring floating structure is set in front of the fringing reef,after the wave passes through the wave elimination effect of the floating structure,there is no wave breaking phenomenon when it continues to propagate along the fringing reef,and the free liquid level on the reef flat is close to zero.In addition,the floating structure has the best wave height attenuation effect on irregular waves,and the worst wave height attenuation effect on solitary waves,and the change of wave height has little effect on its wave height attenuation effect.However,the change of the wave period has a great influence on the wave height attenuation effect of the floating structure,and the floating structure has a poor wave height attenuation effect on long-period waves.The influence of irregular wave on the maximum vertical displacement,maximum pitch angle and maximum sway displacement of floating body structure is smaller than that of regular wave,and the effect of irregular wave is more sensitive to the periodic variation. |
