侧风环境下行驶的直背式轿车气动力计算

分别对直背式简化轿车模型在无侧风、稳态侧风、非稳态侧风三种条件下汽车周围流场进行了数值模拟,并对汽车受到的气动力进行了计算.结果表明,定常侧风会产生较大侧向力,阻力和升力也有一定增加;在非定常侧风作用下,气动力变化趋势与侧风速率变化趋势基本相同.阻力增大幅度较为平缓,侧向力增大较为显著,升力处于两者之间.当侧风增大到一定速率后,车外流场会发生较大变化,尾涡会转变为侧向涡.

Calculation of aerodynamic forces of a car with the effect of crosswind

The outflow field of a simplified fast back car was simulated numerically with the effect of no cross wind,steady cross wind and unsteady cross wind.The aerodynamic forces and coefficients were calculated.The results show that,steady crosswind will generate bigger lateral force,and also increase the drag and lifting force to a certain extent;the change trend of aerodynamic forces was the same as that of lateral wind speed.With the effect of unsteady cross wind,the drag increases more slightly,and the lateral force increases most significantly;the lifting force remains moderately.When cross wind reaches a high level,the flow field will change dramatically,and the wake vortex is turned into side vortex.