表面粗糙度对塑料车身外流场的影响

Influence of rough surface effects on the aerodynamic characteristics of an all-plastic vehicle body

以某全塑汽车车身为模型,应用流体力学数值模拟方法研究表面粗糙度对车身空气动力性能的影响。分别对相同外形不同粗糙度的各模型进行分析,比较各模型气动阻力、气动升力、速度场和压力场之间的差异,并分析造成差异的原因。结果表明,适当增加塑料车身表面粗糙度对气动阻力影响不明显,但是可以降低气动升力。此结论也将对金属车身的设计优化起到积极作用,对金属车身表面进行喷砂等处理,适当增大表面粗糙度会使其气动升力减小。

Using an all-plastic vehicle body model,the influence of different roughness heights of the car body surface on the aerodynamic characteristics has been studied by computational fluid dynamics numerical simulation. By changing the roughness height of the car body surface and comparing velocities and pressures for different models,the reasons for the differences were analyzed. The results showed rough surfaces have no effect on air drag,but can greatly reduce air lift. This may be helpful in increasing the security and economic efficiency of light all-plastic vehicle bodies. The conclusions can also be employed to reduce the air lift of a metal car body.