Research On Aerodynamic Performances Of Car Body In Crosswind

With the development of express highway, and rise of oil price, especially the rapid development of high-speed automotive technology, the consumers have put forward ever-increasing demands on the vehicle power, handling stability, economy and comfort. The research on automotive aerodynamics has become an important part of technique in automotive industry. Being one of the important capabilities of automobile, maneuverability is often affected by crosswind while running. Thus, the stability, under the effect of crosswind, becomes an important component of aerodynamic characteristics of automobile.In this paper, the outflow of automobiles is numerically simulated through mixed-application of CAD and CFD technology. And research the effect of front window on automobile's power performance in crosswinds.First of all, the three-dimensional CAD software UG is used to create the body models with front window angle of 20°, 30°and 45°and their calculating domains. The calculating domains is about 1 times the length of automotive length in front of the car,2 times of the automotive width on both sides of the car,4 times the length of the automotive in rear of the car,3 times the height of the automotive for the height; the mesh generation will be done in software, ICEM-CFD; use ICEM-CFD software to conduct the hexahedral unstructured mesh division on the built three-dimensional body model calculation domain.; the velocity and pressure distributing of some section will be shown. Then the aerodynamic force coefficients will be obtained.From the post processing results, it can be seen that:due to the complexity of the body shape and the interaction of the ground, the external flow is very complicated and shows well developed turbulence. The effect of cross-wind on cars with different front window angles differs, which not only relates to the car styling, but also relates to the vehicle speed and cross wind speed. Under the same condition, compare with the car with front window angles of 20°,30°and 45°,30°angle of the front window has the best Aerodynamic performance. The simulation results of the present study could provide a theory basis for the research on the design of automobile styling and steering system.