Journal of Jilin University(Engineering and Technology Edition) ›› 2019, Vol. 49 ›› Issue (4): 1043-1053.doi: 10.13229/j.cnki.jdxbgxb20180226

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Aerodynamic calculation of MIRA model correlated with wind tunnel test

Hua ZHOU1,2(),Zhi⁃gang YANG1,2,3(),Hui ZHU1,2   

  1. 1. Shanghai Automotive Wind Tunnel Center, Tongji University, Shanghai 201804, China
    2. Shanghai Key Lab of Vehicle Aerodynamics and Vehicle Thermal Management Systems, Shanghai 201804, China
    3. Beijing Research Center, Commercial Aircraft Corporation of China, Beijing 102200, China
  • Received:2018-03-22 Online:2019-07-01 Published:2019-07-16
  • Contact: Zhi?gang YANG E-mail:zhouhua0987826@163.com;zhigang.yang@sawtc.com

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Abstract:

The prediction capability of steady numerical simulation on aerodynamic forces and surface pressure of generic vehicles was clarified. First, a detailed study on mesh scheme for MIRA reference car model was carried out with baseline data derived from full-scale wind tunnel test. Results show that the grid-independent strategy requires 10 mm for car surface mesh, Y +=30 for the first layer grid and 5 layers around the car. Based on this mesh scheme, aerodynamic force calculation of MIRA model could yield satisfactory predictions, that at 0° yaw, the error of drag coefficient C D from test data was 0.34%, error of lift coefficient C L 1.06%, and at 3°~20° yaw conditions, error of C D and side force coefficient C S were respectively no more than 5% and 9%, which indicate the reliability of aerodynamic forces computation for simplified cars like MIRA model. For surface pressure, of all 254 pressure taps all over the car, error of C P over 50% are less than 20%, while surface pressure was poorly calculated mostly where flow is so complicated that separation or reattachment tends to happen, such as the underbody and the leeward side..

Key words: vehicle engineering, aerodynamic force, surface pressure, numerical simulation, MIRA reference car model, wind tunnel test, mesh scheme, yaw conditions

CLC Number: 

  • U467.1

Fig.1

Schematic diagram of MIRA notchback model dimensions"

Fig.2

Schematic diagram of wind tunnel with an open?jet test section"

Fig.3

MIRA notchback model in the wind tunnel"

Fig.4

Distribution of surface pressure taps"

Fig.5

Static pressure measurement tubes inside the car model"

Fig.6

C D variation with wind speed"

Fig.7

Domain dimensions for numerical simulation"

Table 1

Boundary conditions and parameters setup"

边界条件 参数设置
近壁面处理 非平衡壁面函数
阻塞比/% 1.6
MIRA车型正投影面积/m2 1.858
速度入口/（km·h-1） 80
压力出口 一个标准大气压
MIRA车身表面和地面 固定壁面
计算域侧面和顶面 对称壁面

Table 2

Parameters for grid independence study"

变化参数 变化范围
车身面网格尺寸/mm 5~15
车身表面网格Y +值 30~90
车身边界层网格层数 3~10
体网格数量/万个 1361~3753
网格加密形式 尾部加密和整车加密

Table 3

Error of C D and C L for different surface"

面网格尺寸/mm 网格数/万个 ΔC D/% ΔC L/%
15 884 1.35 8.51
10 1726 -0.34 1.06
7.5 2731 -0.34 -1.06
5 5544 0.68 1.06

Fig.8

Error of C P for different surface mesh size"

Table 4

Error of C D and C L for different wall Y + over the car surface"

车身表面Y + ΔC D/% ΔC L/%
30 -0.34 1.06
45 0 13.83
60 -0.68 26.60
90 -2.03 40.43

Fig.9

Error of C P for different wall Y+ over the car"

Fig.10

C P distribution along upperbody centerline"

Fig.11

C P distribution along underbody centerline"

Table 5

Error of C D and C L for different boundary"

边界层层数 边界层厚度/mm ΔC D/% ΔC L/%
3 3.47 -0.34 6.38
5 6.74 -0.34 1.06
8 13.73 0.68 3.19
10 20.30 1.01 -2.13

Fig.12

Error of C P for different boundary layer mesh"

Table 6

Error of C D and C L for different grid density"

体网格总数/万个 ΔC D/% ΔC L
1361 0 -14.89
1726 -0.34 1.06
2662 0 -4.26
3753 -0.68 1.06

Fig.13

Error of C P for different mesh density"

Fig.14

Different mesh refinement types"

Table 7

Error of C D and C L for different types of mesh refinement"

加密方式 网格数/万个 ΔCD/% ΔCL/%
不加密 1726 -0.34 1.06
尾部加密 2834 -0.34 4.26
整车加密 3621 -0.34 1.06

Fig.15

Error of C P for different types of mesh refinement"

Fig.16

Static pressure distribution on backlight"

Fig.17

Static pressure distribution on boot deck"

Fig.18

Static pressure distribution on rear end"

Fig.19

Hybrid grid pattern at longitudinal symmetric plane of flow domain"

Fig.20

Pressure taps where error of C P>50%"

Fig.21

Wall shear stress streamlines over car model"

Fig.22

Velocity streamlines of flow domain at longitudinal symmetric plane"

Fig.23

Boundary setup under yaw conditions"

Fig.24

Comparison between CFD and test results of C D and C S under yaw conditions"

Fig.25

Pressure distribution over MIRA model and on horizontal plane of Z=0.5 m"

Fig.26

Error of C P under different yaw angles"

1 Hucho W H . Aerodynamics of Road Vehicles[M]. Warrendale: Society of Automotive Engineers, 1998.
2 姜乐华, 谷正气 . CFD在汽车空气动力学研究中的应用[J]. 湖南大学学报, 1997, 24(4): 52⁃56.
Jiang Le⁃hua , Gu Zheng⁃qi . The application of CFD methods to automobile aerodynamics[J]. Journal of Hunan University, 1997, 24(4): 52⁃56.
3 傅立敏, 王靖宇 . 汽车三维分离流动特性的数值研究[J]. 汽车工程, 2000, 22(6): 361⁃364, 376.
Fu Li⁃min , Wang Jing⁃yu . Numerical study of separated flow around after⁃body of road vehicle[J]. Automotive Engineering, 2000, 22(6): 361⁃364, 376.
4 严鹏, 吴光强, 傅立敏, 等 . 轿车外流场数值模拟[J]. 同济大学学报, 2003, 31(9): 1082⁃1086.
Yan Peng , Wu Guang⁃qiang , Fu Li⁃min , et al . Numerical simulation of flow field around car[J]. Journal of Tongji University, 2003, 31(9): 1082⁃1086.
5 吴军, 钟志华, 谷正气 . 汽车外流场数值仿真的进一步研究[J]. 机械工程学报, 2003, 39(9): 110⁃113.
Wu Jun , Zhong Zhi⁃hua , Gu Zheng⁃qi . Further study on numerical simulation of flow around automobiles[J]. Chinese Journal of Mechanical Engineering, 2003, 39(9): 110⁃113.
6 Shih T H , Liou W W , Shabbir A , et al . A new k⁃ε eddy viscosity model for high Reynolds number turbulent flows: model development and validation[J]. Computers and Fluids, 1995, 24(3): 227⁃238.
7 张英朝, 薛学栋, 丁伟,等 . 某两厢车气动外形减阻自动优化设计[J]. 同济大学学报, 2016, 44(11): 1771⁃1776.
Zhang Ying⁃chao , Xue Xue⁃dong , Ding Wei , et al . Automobile shape optimization of hatchback to reduce aerodynamic drag[J]. Journal of Tongji University, 2016, 44(11): 1771⁃1776.
8 朱晖, 杨志刚 . 两方程模型计算轿车气动性能的适用性研究[J]. 汽车工程, 2016, 38(11): 1283⁃1287, 1337.
Zhu Hui , Yang Zhi⁃gang . A study on the applicability of two⁃equation models to the calculation of aerodynamic performance of Sedan[J]. Automotive Engineering, 2016, 38(11): 1283⁃1287, 1337.
9 Ashton N , Revell A . Comparison of rans and des methods for the drivaer automotive body[C]∥SAE Paper, 2015⁃01⁃1538.
10 Palaskar P M , Kumar V , Vaidya R . Methodology development to accurately predict aerodynamic drag and lift for passenger vehicles using CFD[C]∥SAE Paper, 2016⁃01⁃1600.
11 Ahmad N E , Abo⁃Serie E , Gaylard A . Mesh optimization for ground vehicle aerodynamics[J]. CFD Letters, 2010, 2(1): 54⁃65.
12 Gaylard A P , Baxendale A J , Howell J P . The use of CFD to predict the aerodynamic characteristics of simple automotive shapes[C]∥SAE Paper, 980036.
13 Zhang Ying⁃chao , Ding Wei , Zhang Yu . Aerodynamic shape optimization based on the MIRA reference car model[C]∥SAE Paper, 2014⁃01⁃0603.
14 Le G G M , Garry K P . On the use of reference models in automotive aerodynamics[C]∥SAE Paper, 2004⁃01⁃1308.
15 Lawson A A , Dominy R G , Sims⁃Williams D B , et al . A comparison between on⁃road and wind tunnel surface pressure measurements on a mid⁃sized hatchback[C]∥SAE Paper, 2007⁃01⁃0898.
16 Gu Zheng⁃qi , Song Xin , Jian Ye⁃jie , et al . Optimization of the realizable k⁃ε turbulence model especially for the simulation of road vehicle[C]∥SAE Paper, 2012⁃01⁃0778.
17 Wang Y , Xin Y , Gu Z , et al . Numerical and experimental investigations on the aerodynamic characteristic of three typical passenger vehicles[J]. Journal of Applied Fluid Mechanics, 2014, 7(4): 659⁃671.
18 龚旭, 谷正气, 李振磊, 等 . 侧风状态下轿车气动特性数值模拟方法的研究[J]. 汽车工程, 2010, 32(1): 13⁃16.
Gong Xu , Gu Zheng⁃qi , Li Zhen⁃lei , et al . A study on the numerical simulation of car aerodynamic characteristics under crosswind conditions[J]. Automotive Engineering, 2010, 32(1): 13⁃16.
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