侧风对轿车气动特性影响的数值模拟研究

选用某国产轿车1∶1模型,利用混合网格方案对不同强度侧风作用下的轿车外流场进行数值模拟,得到不同侧风强度下的流场速度压力分布及气动力系数变化情况.分析不同强度的侧风作用下的流场速度和压力分布,着重分析了尾部流场的变化,定性地解释了侧风对轿车气动力特性的影响,初步研究了尾流随侧风作用的变化机理.模拟结果表明,该车型在不同强度侧风作用下,侧向力系数和升力系数均随着侧风作用的增强而增大.研究结论为深入分析侧风作用下轿车外流场特性提供了有利的参考.

Numerical simulation of the crosswind effects on the aerodynamic performance of a sedan

A 1:1 car model is chosen for the study and the hybrid meshes composed of tetrahedral meshes,prism meshes and hexahedral meshes are employed in the numerical simulation.The flow field around a sedan under the effects of the crosswind with different intensity is simulated and the qualitative analysis is performed of the phenomena that the side force and the lift change under different crosswind intensity according to the velocity and the pressure distribution of the flow field,which reasonably interrupt the changing C_S and C_L calculated.The results of computation show that both the C_S and C_L augment remarkably as the crosswind increases.The analysis results provide the helpful reference to catch the flow field characteristics under the effect of the different crosswind intensity,and the transient numerical simulation study of the flow field around the car under the crosswind effects can be based on these results.