Research On Aerodynamic Characteristics Of Vehicle During Crossing Each Other

With more and more cars, people require more and more car performance of operation stability, security and comfort, meanwhile the aerodynamic features has direct relation with this performance. While crossing with each other, flow around vehicles affect each other and pressure changes with time changing, which lead to the changes of drag, side force and yaw moment. It will affect much on stability and security of cars. Research on vehicle aerodynamics at home and abroad have been done by many people, which mostly focus on single car and train meeting, but less on research about aerodynamic characteristics of car crossing each other. Scholars from Jilin University have done some research on the vehicle transient aerodynamic characteristics during crossing each other and research on the effects of aerodynamic characteristics by transverse distance and speed.This paper studies three-dimensional flow filed during crossing by numerical simulation, aiming to discuss about the law of aerodynamic characteristics changing and the tendency of aerodynamic features with different transverse distance and speed. Apply CATIA software to create MIRA three-dimensional model, use software gambit to do the mesh for the domain and use software FLUENT to do numerical simulation for single car flow field. Compared numerical simulation result with test value, margin of error is within10%to ensure simulation correctly.Then apply dynamic mesh technology inside FLUENT to do transient numerical simulation during crossing, analyze the change of flow around car during crossing, seize the rule along with change of drag coefficient, lift coefficient and lateral force coefficient. The results show three kinds of aerodynamic coefficient all changes like sine curve. Last do transient numerical simulation at4different speed and3different transverse distance according to technical standard of highway engineering and do research on which effects speed and transverse distance bring. The results show that aerodynamic interference generated by the two vehicles is greater when transverse distance is smaller or car speed is bigger. Therefore safe transverse distance between two cars and certain crossing speed which is not too high must be guaranteed during crossing each other. In sum, this paper does a deep research on crossing process in vehicle aerodynamic perspective. For one side, it provides reference for driver to select reasonable transverse distance and crossing speed, and for another one, it provides theory reference for our country’s research on smart vehicle technology.