Numerical Simulation Study On The Influence Of Wind Barrier On The Aerodynamic Performance Of Trains And Bridges Under Cross-wind

Hourly train speed is strictly controlled to align with the safety requirements in an environment of strong wind condition.Wind barriers installed on both sides of the railway is an effective method to improve the aerodynamic performance of the bridges.However,excessive wind barriers will adversely affect the aerodynamic performance of the bridge itself.In this paper,it applied CFD numerical simulation to elaborate on the aerodynamic characteristics of the wind-vehicle-bridge system of a road-rail bridge when the train is stationary and moving.Then it analyzes the impact of different wind barrier parameters on the aerodynamic performance of the vehicle-bridge system and the aerodynamic performance of the vehicle-bridge system.The corresponding conclusions and design guidance recommendations are stated as follows:(1)It has introduced the related theory of computational fluid dynamics,and compared and studied four different mesh update methods for moving trains.Due to the large difference in the characteristic sizes of trains,bridges and wind barriers,it used a structured grid to divide the train-bridge-wind barrier model as a whole in order to ensure the accuracy of calculations.This division method is better than tetrahedral unstructured grids or hybrids.Grid has the advantages of high accuracy and low consumption of computing resources,which provides a basis for the calculation of subsequent mobile trains.(2)It has carried out numerical simulation of the aerodynamic characteristics of the vehicle-bridge-wind barrier under static conditions and compared with the wind tunnel test results to verify the accuracy of the numerical simulation method.Besides,it has investigated the changes of the three-component force coefficient of trains and bridges with the height of the wind barrier and the air permeability rate.The results indicate that the change of the three-component force wind barrier height of the bridge is more sensitive than the change of the air permeability rate.Finally,the DEA method is used to evaluate the efficiency of the three-component force coefficients of the vehicle and the bridge with the considerations of overall factors of the vehicle and bridge.In addition,it outlines the optimal parameter values of wind barrier under static conditions.(3)In order to better simulate the changes in the aerodynamic performance of the train passing through the wind barrier under different wind barrier permeability,it uses the dynamic layering method to achieve the dynamic calculation of the moving train.It has studied the wind shielding effect of the closed wind barrier on the moving train under the action of cross winds of 10m/s,20m/s and 30m/s and clarified the influence of different wind barrier permeability on the aerodynamic force of the moving train,and obtained the best wind.The air permeability of the barrier is compare the impact of moving trains on wind barriers with different air permeability rates,providing a reference for the design of similar wind barriers.