Numerical Simulation On Aerodynamic Characteristics Of Vehicles And Bridges Under Cross Wind

At present,more attentions are paid to the safety of vehicles moving on the bridge under the strong wind.Hence,more and more researchers pay more attentions to the wind-vehicle-bridge(WVB)coupled system.In this paper,the three-dimensional numerical simulations were carried out to investigated the aerodynamic characteristics of vehicles and bridges under cross winds.Then,the difference of drag force coefficient obtained by the global force measurement and pressure distribution methods is analysed.The aerodynamic characteristics of vehicles and bridges under the interaction of the WVB system are studied.Specific studies are as follows:1.First,the latest researches concerning the aerodynamic characteristics of wind-vehicle system,vehicle-bridge system,and wind-vehicle-bridge system are reviewed.Conclusions about their methods on these researches are draw to study the advantages and shortcomings of their methods.Then through the shortcomings,the breakthrough point is seized and the research ideas in this paper are identified.2.In light of the methods on research contents,the computational fluid dynamics theory including the three equations and turbulence models,development and application of numerical simulation technology and moving mesh methods are introducted in detail.3.In view of the difference of drag force coefficient obtained by the global force measurement and pressure distribution methods,the Sutong Bridge's cross section,flat plate and rectangular cylinder were chosen as the typical sections in this paper,and the three-dimensional numerical simulations were carried out under different conditions.The accuracy of the numerical simulation method adopted in the present study is proved.Then the trends of drag coefficient and pressure drag coefficient of the three sections varying with the wind attack angles and velocities were investigated.Meanwhile,the reasons of their different variations were discussed.Furthermore,the effects of handrail on the total drag coefficient and pressure drag coefficient of the Sutong Bridge's girder section were analyzed.The total drag coefficient and pressure drag force coefficient varying with the ratio of width to height and wind fairing angle were investigated.The variation law of the contribution ratio of the friction drag to the total drag and the effect of Reynolds numbers on it were discussed.When the wind velocity is 12 m/s,correction coefficient of the drag force coefficient obtained by pressure distribution methods for streamlined section varying with different aspect ratio and wind fairing angle was obtained by the least square method.This findings can provide a reference for their applicability in the engineering practice.4.Similar to the above reaseach,numerical simulation method is taken to analyse WVB system and investigate the aerodynamic parameters of the bridge when the MIRA car and lorry respectively parked on different lanes of the bridge under the cross wind.Meanwhile,the aerodynamic parameters of the MIRA car and lorry are investigated varying with wind angle,wind attack angle and lane position.What's more,the aerodynamic parameters of WVB system are studied when the vehicle moving on the bridge.