基于Fluent软件的客车高速发飘分析

Analysis of Fat Gone with the Wind of bus high speed based on Fluent software

客车在高速运行的情况下会产生较大的空气升力与阻力，这些气动力会降低轮胎的侧偏刚度，使得在方向盘输入时横摆角速度达到稳态的反应时间较长，超调量较大，给驾驶员的感觉是车辆飘忽不定。这里通过将建立的三维Catia客车外形模型导入Fluent软件中进行仿真，在不同车速下计算出气动升力和阻力，再将其转化为轮胎侧偏刚度的变化作用于多自由度客车动力学模型，研究在力阶跃输入下的客车发飘现象。

It will generate bigger aerodynamic lift and resistance when the bus is operating in high speed,these aerodynamic lift can reduce the cornering stiffness of tyre,which makes long reaction time of yaw velocity to reach a steady state when the steering wheel input,large overshoot,which brings the feel to driver that the vehicle is not stable.Here make simulation by leading in three dimensional outernal model of Catia bus to Fluent software,calculate aerodynemic lift and resistance under different vehicle speed,and then transfer to tyre cornering stiffness modification effected into Multi-DOF bus dynamics model,reseach the bus floating phenomenon under power step input.