Study On Aerodynamic Characteristics And Windproof Measures Of Freight Vehicles On High Pier Bridges

In recent years,with the rapid development of highway bridge network,the scale of automobile industry expands and the logistics industry develops vigorously.Commercial vehicles such as freight vehicles are playing an increasingly important role in highway transportation.When cars drive on high pier Bridges,they are often affected by environmental crosswise winds,which have a great impact on the handling stability and safety of cars,and even cause traffic accidents.Therefore,it is of great practical significance to study the driving stability of freight vehicles under crosswind influence on high pier Bridges to ensure their driving safety.In this thesis,with the help of CFD numerical simulation method,Catia and Starccm+ software were used to establish the model of vehicle,bridge and wind barrier and the division of grid cells.The flow field characteristics of freight vehicles under the action of crosswise wind were studied in depth by using the principle of computational fluid dynamics.The aerodynamic load characteristics of freight vehicles on the bridge under different wind speed,speed,wind Angle and other parameters were analyzed,and the wind resistance effect after setting the wind screen was also analyzed.Finally,the cross wind safety operation of freight vehicles on the bridge was evaluated,so as to provide reliable basis for ensuring the safe driving of freight vehicles.This thesis takes Globetrotter XL as the research object,establishes its numerical model,and simulates its aerodynamic characteristics.The main research contents include:(1)Calculate and simulate the surface pressure distribution law and outflow field characteristics of freight vehicles running on high-pier Bridges in the presence or absence of crosswise,get the pressure and velocity cloud diagram,and get the flow field distribution law and aerodynamic characteristics change law around the freight vehicles.(2)By changing the vehicle speed,wind speed,wind direction Angle and other parameters,study its influence on the aerodynamic load of freight vehicles,and analyze the variation rule of aerodynamic load.The results show that the aerodynamic force of freight vehicles increases gradually,and the changes of vehicle speed,wind speed,wind direction Angle,lane position and other parameters have a great impact on the aerodynamic load of vehicles.(3)Set solid and fence type wind shields respectively to simulate the flow field coupling characteristics of vehicle-bridge-wind barrier system,and conduct a comparative study with the automobile wind field without wind shields.The flow field distribution of vehicle-bridge-wind barrier system is studied by changing the speed of freight vehicle and wind speed,and its influence on the dynamic coefficient of freight vehicle and windbreak hold is analyzed.(4)Study the effect of solid windbreak screens with different heights.This thesis studies the effect of different height and different ventilation rate of fence type windbreak screen,and determines the best form of windbreak screen.(5)The safety of roll and sideslip of freight vehicles under crosswind is analyzed,and the safety limits of speed and wind speed under different road conditions are obtained.