车速对超车车辆瞬态气动特性的影响

Influence of velocity on transient aerodynamic characteristics of overtaking and overtaken vehicles

为了研究超车过程中相对车速和绝对车速对汽车气动特性的影响,采用动网格技术实现了超车过程的三维瞬态数值模拟。研究结果表明:超车过程中,相对车速对主超车的影响较小,对被超车的影响很大。被超车侧向力系数和横摆力矩系数的变化量随两车相对车速的增加呈线性增加的趋势。在相同的相对速度下,绝对速度较低的两辆车在超车过程中产生的瞬态气动影响更大。

The dynamic meshing technique was adopted to realize the 3-D transient numerical simulation of vehicle overtaking process in order to study the influence of relative velocity and absolute velocity on the aerodynamic characteristics of the overtaking and overtaken vehicles during the overtaking process. The simulation results show that the relative velocity has a little influence on the overtaking vehicle but much influence on the overtaken vehicle during the overtaking process. With the increase of the relative velocity, the variations of side force coefficient and yawing moment coefficient of the overtaken vehicle will increase linearly. Under the same relative velocity, two vehicles with slower absolute velocities have more transient aerodynamic influence on each other during the overtaking process.