小轿车绕流流场的三维数值模拟

Numerical Simultation of the External Flow Around a Car Body

利用商用计算流体力学(CFD)软件PHOENICS与CAD软件相结合,对长安奥托SC7081A型小轿车周围流场进行了三维数值模拟,重点分析了小轿车尾部的湍流情况。结果表明:由于小轿车外形的复杂性和地面效应,面包车周围的流场极其复杂且表现出三维湍流特征;在汽车尾部区域,由于气流在此处突然失去附着,形成马蹄涡和拖拽涡,使尾部气流的流动状况变得更加复杂,大尺度涡的形成使得气流耗散的能量增加,从而使汽车的阻力显著增大。

Using the PHOENICS software with CAD, the 3-dimensional airflow around a car is numerically simulated, the wake flow is discussed in detail. The results show 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. In the wake area, because of the appearance of flow separation and towing vortices, and the formation of the horseshoe vortices, the drag is in general increased.