Research On Wave Slamming Of Suspended Square Box And Box Grider

With the rise of sea level caused by climate warming,the clearance between the bridge and the sea gradually decreases.The superstructure of the existing low clearance bridge may suffer from wave action and damage under the action of storm surge and typhoon.According to the different water level,the superstructure of bridge can be divided into suspended state,contacting water state and completely submerged state under wave action.Among them,there are obvious phenomena of air capture,slamming and wave breaking in the suspended wave action,and its physical mechanism is very complex.At present,the research on this aspect is relatively scarce at home and abroad.In this paper,the square box is taken as the research object,and the wave action process on the square box in the suspended state is studied by numerical simulation and hydrodynamic test.For the purpose of comparative analysis,the same type of research is carried out for the box girder which is similar to the square box structure.The main research contents and results are as follows:(1)Based on FLUENT software,the numerical flume model is established.Aiming at the problem of excessive wave attenuation in numerical simulation,the parameter setting of numerical model is adjusted,and the reason of excessive wave attenuation is analyzed.Furthermore,the grid independence of wave making and force is verified and the appropriate grid size is selected.The influence of reflected waves is eliminated by setting the source term of the governing equation.Through the comparative analysis of numerical simulation wave making and wave theory wave surface equation,it is verified that numerical flume simulation can generate the target wave better(2)Based on Froude similarity criterion,the hydrodynamic experiments of 1:25scale bridge box girder under regular waves are carried out.The purpose of the test is to study the influence of wave on the wave load and its distribution under different wave height,period and clearance conditions;Based on the principle of the same geometric size of the bottom,the hydrodynamic tests of the same type for the box girder are carried out.(3)Through numerical simulation and model test,the wave load on the square box under regular waves is studied,and the numerical simulation results are compared with the experimental results.The effects of wave height,wave period,clearance on the horizontal,vertical slamming pressure and slamming force,as well as the distribution of bottom pressure are studied.The mechanism of the impact of the other box is explained.By comparing the horizontal and vertical pounding between the opposite box and the box girder,the difference and relation between the two structures subjected to the wave action are obtained...