Flow Characteristic Investugation Of High-speed Trains-bridge Structure Under Wind-wave Actions

With development of "Belt and Road" strategy,high-speed railways have gradually extended from inland areas to coastal areas.Complicated marine environments often experience strong winds,huge waves and even tsunamis,which pose a huge threat to the safety of bridges and train operations.With the high speed and light weight of high-speed trains,it is difficult for single wind or single wave research to fully reflect the complex marine environmental load on the train-bridge structure.The combined effect of wind and wave on the safety of cross-sea highspeed railway bridges and traffic It becomes a controlling factor affecting the safe operation of high-speed railway bridges across the sea.In this paper,the numerical simulation method is used to study the flow characteristics of the high-speed trainbridge structure under the combined action of wind and waves,and to reveal the influence of different flow field environmental conditions on the characteristics of the flow field around the train-bridge system.Research on safety and control methods provides the basis.The main research contents of this article are as follows:First,based on the Fluent software platform,using boundary wave method,VOF to capture free liquid surface and resistance wave elimination technology to establish 2D and 3D numerical wave flume,complete the stable second-order Stokes wave simulation,and through the wave time history,spatial waveform and The comparison of water mass velocity and other parameters with the theoretical wave parameters verifies the correctness of the simulation results.Based on the above numerical water tank,the designed horizontal wind speed is set in the air phase to simulate the stable wind-wave joint action field.The wave parameters and wind field parameters verify the feasibility and correctness of the wind-wave joint action field in the numerical water tank.Subsequently,numerical simulations of standard square columns,rounded square columns,two-sided columns,and the Danish Great Belt East Bridge were carried out,and the correctness of the simulation method was verified by comparison with existing literature.Trains and bridge structures were added to the abovementioned numerical wave troughs.Through numerical simulation of different working conditions such as single wind,single wave,wind-wave combination,etc.,wave aerodynamic interference,train intersection,wind barrier,and tower shielding effect were studied.The factors are aerodynamic characteristics and flow field characteristics of the vehicle-bridge system.The simulation calculation results show that the wave motion drives the upper air velocity to change periodically under single wave conditions,resulting in periodic changes in the aerodynamic coefficients of the train and bridge structure.The change period is consistent with the wave period;compared with the single wind condition,the wind-wave Under combined operating conditions,the aerodynamic characteristics of the following vehicle-bridge structures are significantly enhanced,and the coefficient of lift resistance is significantly increased,and due to the unevenness of the aerodynamic interference of the waves,the flow around the fluid is more complicated and variable.