Abstract: The influence of vehicle aerodynamic characteristics on its performance plays a more and more important role with the improvement of vehicle speed. Using the method of CFD numerical simulation, taking Mira model as the research object, the prototype and the model with rear spoiler were simulated. By studying the flow field and velocity around the model, the effects of different tail Mira models, the installation of rear spoiler and the rear spoiler with different section shapes and angles of attack on the aerodynamic characteristics were analyzed. The research shows that there are obvious differences in the wake structure due to different body tail shapes, which has a great impact on the aerodynamic characteristics of the vehicle. At the same time, properly installing the rear spoiler at the rear of the vehicle can well optimize the wake structure of the vehicle body, so as to improve the aerodynamic characteristics of the vehicle.

Key words: vehicle engineering; aerodynamics; CFD; outflow field; Mira model; rear spoiler

摘要： 汽车的空气动力学特性对其性能的影响，随着车速的提高占据了越来越重要的地位。运用CFD数值模拟的方法，以Mira模型为研究对象，对其原型以及加装后扰流板模型进行仿真。通过研究模型周围流场、速度等，分析不同尾部Mira模型、加装后扰流板，以及截面形状与攻角不同的后扰流板对气动特性的影响。研究表明：车身尾部造型不同，尾流结构有明显的区别，对汽车空气动力学特性的影响很大。同时，在车尾恰当加装后扰流板，能够很好地优化车体尾流结构，从而提高车辆的气动特性。

关键词: 车辆工程；空气动力学；CFD；外流场；Mira模型；后扰流板