汽车超车过程的空气动力特性研究

采用稳态和瞬态两种方法,对两辆车超车过程中外部流场的空气动力特性进行了数值模拟研究。采用网格变形和局部网格重构相结合的动网格技术,并耦合刚体动力学方程和PISO算法实现了汽车超车过程的三维瞬态数值模拟。通过稳态和瞬态计算,探讨了超车过程中两车纵向相对位置对气动特性的影响以及气动力对汽车行驶稳定性的影响。研究发现超车过程中被超车的阻力、侧向力和横摆力矩都有最大值,并找出了其变化规律。通过对稳态与瞬态计算结果的比较,可以看出:本文采用的瞬态模拟方法能够充分捕捉超车过程中的动态效应,优于传统的稳态模拟。

Research on aerodynamic characteristics during the vehicle overtaking process

The steady and transient numerical simulation methods are adopted to research the aerodynamic characteristics of external flow field during the overtaking process.Dynamic mesh method combining mesh deforming with local remeshing, rigid body dynamics equation and PISO algorithm are adopted to realize the three-dimensional transient numerical simulation of vehicle overtaking process.According to the steady and transient simulation results,discuss the effect of longitudinal relative positions on the vehicle aerodynamic characteristics during the overtaking process and the effect of aerodynamic forces on the driving stability.Research indicates that during the overtaking process the drag,side force and yawing moment of overtaken vehicle have the maximum value and their change laws are found.By comparison with steady and transient results,we can conclude that transient simulation can capture the dynamic effect during the overtaking process sufficiently and it is better than the traditional steady simulation.