Study On Security Of Automobile Base On Aerodynamics

The automotive aerodynamics characteristics are very important performance of the automotive and the automotive stability in the condition of crosswind acts a very important part in the automotive aerodynamics characteristics. The operation performance of the automotive is often affected by the cross wind and the steering safety will be destroyed when the cross wind picks up. With the strengthening of cross-winds and the yaw angle of large and increasing vehicle speed, vehicle traffic will have a great security threat. The future trend towards lightweight cars will exacerbate the sensitivity to crosswinds.For the above problem, according to Xi_hua University judicial identification of the motor vehicle, make use of the typical cases and the various types of motor vehicles" different aerodynamic characteristics .then study the high-speed vehicle's safety characteristics basing on the aerodynamics. The conclusion of the study subjects could provide an important reference to the design of automotive safety technology; it can also be applied to road safety campaigns to education and controlling systems. Controlling traffic flow for the correct and reasonable traffic speed, reducing traffic accidents, and it is an important protection to traffic safety.Although the collection of force and moment data through wind tunnel tests can provide information regarding the principal forces and moments influencing a vehicles response in a crosswind. they fail to identify the specific regions on the vehicle that contribute to these aerodynamic loads and to give us the intuitionistic understandings of the flow field around the cars and could not provide details of the fluid dynamics involved. The numerical simulation of the flow field around a car can give the distribution of the pressure and the velocity in every place of the flow field and can give the intuitionistic understandings of the generation and development of the separation and the vortices, which is very helpful for the thorough study of the crosswinds stability.The method of resultant velocity wind is employed in this study program .In this method the yawed resultant winds is applied corresponding to the crosswinds and the movement of the automotive. The hybrid meshes combined of tetrahedral meshes and hexahedral meshes are employed in the numerical simulation.Then we will analysis the Flow field around the body according to the simulation results. And study flow fields at different positions on the speed and pressure distribution of the car's body. And analysis of the role of cars by the side wind lift when the lateral force and the corresponding changed. Basing on the GB7258 standards, Study on the impact of aerodynamic lift on the model cars to traffic safety.The main conclusions are:When the speed of the car and speed of the cross-wind are constant, Aerodynamic lateral force and Aerodynamic lift Increase Obviously With the increase of the Yaw angle.When the speed of the car and yaw angle is constant, the aerodynamic side force and aerodynamic lift are obviously enhanced with the cross-wind increases.When the cross-wind size and yaw angle are constant, the aerodynamic side force and aerodynamic lift are obviously enhanced with the increase of car's speed.To sum up: when Automobile is in a high speed, airflow directly Impact the Aerodynamic lateral force and Aerodynamic lift, Aerodynamic lift directly Impact turning ability of the Automobile. Therefore it Impacts the controlling Stability of the Automobile. The results of the analysis could provide useful Reference when we study the Flow field out of the Automobile .It also could provide a basement when we do the twinkling Simulation out of the automobile .we can account Aerodynamic and Aerodynamic coefficient, and then provide Reference for traffic safety.