车身单一非光滑表面与双表面耦合的减阻效果

Drag reduction effect between single non-smooth surface and coupled double surface of motor

将凹坑型非光滑表面分别布置在汽车工业研究协会(MIRA)给出的直背式模型的顶部和尾部,研究顶部非光滑和尾部非光滑单独作用时的减阻效果,并通过耦合的方法,研究顶部和尾部共同作用时的减阻效果.通过CFD数值计算方法,得出模型的尾流、压力、剪应力以及湍动能等参数,对比模型在不同形式下的减阻效果,并分析减阻原因.研究结果表明:凹坑型非光滑表面能减小模型尾部负压,从而减小压差阻力,并降低湍动能,减小能量耗散;顶部和尾部非光滑的耦合作用略强于单独作用,但小于两者之和.

Pit-type non-smooth surfaces were arranged in Motor Industry Research Association(MIRA)fastback model′s top and tail,and the drag reduction effect when acting alone was studied.And through the coupling method,the drag reduction effect of top and tail together was researched.Through computational fluid dynamics(CFD)numerical calculation method,the wake,pressure,shear stress and turbulent kinetic energy and other parameters were obtained,drag reduction effect in different states were compared,and the reasons for drag reduction were analyzed.The results show that pipe-type non-smooth surface can reduce pressure on the tail,thereby reducing the differential pressure resistance,turbulence kintic energy and energy dissipation.The coupling effect of nonsmooth top and tail is slightly stronger than the separate effect,but less than the sum of both.