车身气动阻力直接影响汽车的动力性和燃油经济性,尾涡结构对于车辆空气阻力的形成有很大的影响,非光滑结构在车身的合理布置能有效地减小汽车的空气阻力。为了研究车身非光滑结构对汽车尾涡结构的影响与控制,将凹坑型非光滑单元分别布置在MIRA阶梯背模型尾部、顶部、行李舱盖等表面,运用计算流体力学(Computational fluid dynamics, CFD)数值仿真与风洞试验相结合的方法,对比分析车身表面光滑模型与车身表面非光滑模型尾部流场的压力、湍流耗散率、速度矢量等参数的影响,探讨非光滑结构的扰动效应及其对尾涡形成的控制作用,得出非光滑结构能延迟气流分离,控制后风窗上猫眼涡与尾部剪切涡流,也能抑制汽车尾部主涡的生成。为有效控制车辆尾迹中旋涡结构,抑制涡激振动,改善汽车气动特性提供重要依据。
The aerodynamic drag of the body directly affects the power performance and fuel economy of the vehicle. Trailing vortex structure for vehicle has great effect on the formation of air resistance. The reasonable arrangement of the non-smooth structure in the body can effectively reduce the air resistance of the car. In order to study the influence and control to automobile tail vortex of the structure of non-smooth body, this article has pit type non-smooth units respectively arranging in the MIRA ladder back model of the top of the automobile and the trunk deck surface and the top of the automobile tail. By using the method of computational fluid dynamics(CFD) numerical simulation and wind tunnel test combination to comparative analysis of non-smooth surface of the tail of the model of pressure, turbulent dissipation rate, velocity vector and the effects of other parameters. The effect of non-smooth structure perturbation and the control of the formation of wake vortex are investigated. Concluded that the non-smooth structure can delay the flow separation,control the wind window on the cat and the tail vortex shear vortex and restrain the generation of the main vortex in the rear end of the vehicle. For the effective controlling of the wake vortex structure of the automobile, inhibition of vortex-induced vibration, improving the aerodynamic characteristics of the car to provide important basis.
[1] GU Yunqing,ZHAO Gang,ZHENG Jinxing,et al. Experimental and numerical investigation on drag reduction of non-smooth bionic jet surface[J]. Ocean Engineering,2014,81：50-57.
[2] DING Lixia,SHI Weiping,LUO Hongwen. Numerical simulation of viscous flow over non-smooth surface[J]. Computers and Mathematics with Applications,2011,61(12)：3703-3710.
[3] TIAN L M,REN L Q,JIANG X,et al. Study on drag reduction characteristic around bodies of revolution with bionic non-smooth surface[J]. Natural Science,2010,3(2)：253-254.
[4] 谌可. 非光滑车表汽车的空气阻力特性分析[D]. 杭州：浙江大学,2013.
CHEN Ke. Study of aerodynamic drag feature on automobile with non-smooth surface[D]. Hangzhou：Zhejiang University,2013.
[5] 杨易,聂云,范光辉,等. 车尾凹坑非光滑表面气动减阻分析与优化[J]. 中国机械工程,2013,24(24)：3396-3401.
YANG Yi,NIE Yun,FAN Guanghui,et al. Analysis and design of aerodynamic drag reduction on vehicle rear end by using pit non-smooth surface[J]. China Mechanical Engineering,2013,24(24)：3396-3401.
[6] 金益锋,谷正气,容江磊,等. 汽车凹坑型非光滑表面减阻特性的分析与优化[J]. 汽车工程,2013(1)：41-45.
JIN Yifeng,GU Zhengqi,RONG Jianglei,et al. Analysis and optimization on the drag reduction characteristics of car with pit-type non-smooth surface[J]. Automotive Engineering,2013(1)：41-45.
[7] 王师. MIRA模型组气动特性模型风洞试验研究[D]. 长沙：湖南大学,2011.
WANG Shi. Experimental investigation on aerodynamic characteristics of MIRA model group in wind tunnel[D]. Changsha：Hunan University,2011.
[8] 张成春. 旋成体仿生非光滑表面流场控制减阻研究[D]. 长春：吉林大学,2007.
ZHANG Chengchun. Simulation on flow control for drag reduction of revolution body using bionic dimpled surface[D]. Changchun：Jilin University,2007.
[9] 徐中,赵军,吴正华,等. 凹坑形非光滑表面的减阻性能分析[J]. 航空精密制造技术,2009,45(1)：33-34.
XU Zhong,ZHAO Jun,WU Zhenghua,et al. Analysis of reduction on concave non-smooth surface[J]. Aviation Precision Manufacturing Technology,2009,45(1)：33-34.
[10] 张国耕. 车身仿生非光滑表面气动减阻特性研究[D]. 杭州：浙江大学,2010.
ZHANG Guogeng. Mechanism research on aerodynamic drag reduction of vehicle body with bionic non-smooth surfaces[D]. Hangzhou：Zhejiang University,2010.
[11] 杨歌. 主动凹坑变形湍流减阻控制方案研究[D]. 北京：清华大学,2009.
YANG Ge. Study on control schemes for turbulence drag reduction by active dimple deformation[D]. Beijing：Tsinghua University,2009.
[12] 谷正气. 汽车空气动力学[M]. 北京：人民交通出版社,2005.
GU Zhengqi. Automotive aerodynamics[M]. Beijing：China Communications Press,2005.
[13] 杨易,范光辉,聂云,等. 基于SAE模型非光滑表面对气动减阻的影响[J]. 机械科学与技术,2014,33(4)：559-563.
YANG Yi,FAN Guanghui,NIE Yun,et al. The influence of non-smooth surface effects on aerodynamic drag reduction based on SAE model[J]. Mechanical Science and Technology for Aerospace Engineering,2014,33(4)：559-563.
[14] 张群峰,王望予,傅立敏,等. 轿车尾流移测试验研究[J]. 兵工学报,2000,32(1)：57-60.
ZHANG Qunfeng,WANG Wangyu,FU Limin,et al. Experimental study on flow shift measuring car tail[J]. Acta Armamentarii,2000,32(1)：57-60.
[15] 傅立敏,张群峰,靳春宁. 汽车尾迹涡的形成及其控制[J]. 汽车工程,2000,19(1)：45-47.
FU Limin,ZHANG Qunfeng,JIN Chunning. The mechanism and the control of the road vehicle wake vortices formation[J]. Automotive Engineering,2000,19(1)：45-47.
[16] 吴德久,胡兴军,杨博. 阶背式轿车模型尾流场仿真研究[J]. 汽车工程,2014,36(7)：790-793.
WU Dejiu,HU Xingjun,YANG Bo. A simulation study on the wake field of a notchback car model[J]. Automotive Engineering,2014,36(7)：790-793.
