应用动态耦合法的车辆侧风稳定性研究

Dynamic Coupling Analysis of the Crosswind Stability of a Vehicle

侧风环境中,桥塔周围的流场复杂多变,车辆通过该区域易发生侧滑、侧偏运动,严重威胁行车安全。采用计算流体动力学(CFD)与多体系统动力学(MBD)动态耦合法研究侧风环境下车辆通过桥塔区域时的侧风稳定性。应用重叠网格技术实现车辆在CFD模拟中的运动。建立车辆MBD模型,并通过参数研究验证其鲁棒性。通过风洞试验得到的不同偏航角下的气动阻力系数,验证了CFD的可靠性。将动态耦合法与静态耦合法进行对比分析。结果表明,动态耦合法中的侧向位移与横摆角均大于静态耦合法中的结果。车辆外流场对车辆运动状态非常敏感。动态耦合可以更准确捕捉流场信息,研究车辆侧风稳定性应考虑气动力和车辆动态响应之间的相互作用。

In the crosswind environment,the flow field around the bridge pylon is complex and variable,and the vehicle is prone to side slip and side shift movement through the area,which seriously threatens driving safety. In this paper,a dynamic coupling method is proposed,which uses Computational Fluid Dynamics(CFD)combined with Dynamics of Multi-body System(MBD)to study the crosswind stability of vehicles passing through the bridge pylon area in a crosswind environment. The overlapping grid technique is applied to realize the motion of the vehicle in CFD simulation. The vehicle MBD model is established and its robustness is verified by parametric studies. The reliability of CFD was verified by the aerodynamic drag coefficient at different yaw angles obtained by wind tunnel test. The dynamic coupling method is compared with the static coupling method. The results show that the lateral displacement and yaw angle in the dynamic coupling method are larger than those in the static coupling method.The impact of the flow field on the car is sensitive to changes in the movement of the car. Dynamic coupling can accurately capture flow field information. The study of vehicle crosswind stability should consider the interaction between aerodynamic forces and vehicle dynamic response.