Journal of Jilin University(Engineering and Technology Edition) ›› 2023, Vol. 53 ›› Issue (5): 1289-1296.doi: 10.13229/j.cnki.jdxbgxb.20210940

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Optimization on distortion grid of vehicle external flow field based on Laplacian Algorithm

Yong ZHANG1,2(),Feng-zhao MAO1,Shui-chang LIU1(),Qing-yu WANG1,Shen-gong PAN1,Guang-sheng ZENG1   

  1. 1.School of Mechanical Engineering，Hunan University of Technology，Zhuzhou 412007，China
    2.State Key Laboratory of Advanced Design and Manufacturing of Automotive Bodies，Hunan University，Changsha 410082，China
  • Received:2021-09-17 Online:2023-05-01 Published:2023-05-25
  • Contact: Shui-chang LIU E-mail:834130255@qq.com;289714423@qq.com

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Abstract:

In order to realize the high precision simulation of the vehicle external flow field， the grid distortion position is explored on the basis of analyzing the distortion grid quality evaluation criteria，with the simplified car model in actual use as the research object. In order to prevent the negative volume phenomenon caused by the deviation of the center node during the optimization of the volume mesh， the length weighted Laplacian algorithm is proposed to carry out the simulation calculation of the local optimization of the distortion grid， and verified by the test results of HD-2. The results show that the transition areas of the body side feature line，the front windshield and hood，the rear windshield and luggage lid are prone to volumetric grid distortion.The length weighted Laplacian algorithm can reduce the number of distorted grids， increase the simulation accuracy of the drag coefficient by 3.90%， and the error from the wind tunnel test is 2.26%.The simulation of vehicle tail flow field is more accurate than before the optimization compared with the PIV test， which shows the effectiveness of the length weighted Laplacian algorithm.

Key words: vehicle engineering, grid distortion optimization, Laplacian algorithm, CFD simulation accuracy, wind tunnel experiment

CLC Number: 

  • U461.1

Fig.1

Definition of aspect ratio of quadrilateral"

Fig.2

Definition of aspect ratio of triangle"

Fig.3

Definition of aspect ratio of tetrahedron"

Fig.4

Definition of triangle skew rate"

Fig.5

Definition of quadrilateral skew rate"

Fig.6

Global coordinates of any straight-sided quadrilateral element"

Fig.7

Failure diagram of Laplacian algorithm"

Fig.8

Schematic diagram of Laplacian optimization algorithm"

Fig.9

Model size of car model（Unit：mm）"

Fig.10

Computational domain of vehicle model"

Fig.11

Grid of longitudinal symmetry plane"

Fig.12

Tetrahedral mesh"

Fig.13

Prismatic grid"

Fig.14

Optimized tetrahedral and prismatic grids"

Table 1

Boundary conditions"

计算域边界边界条件设置
入口速度/(m·s-1)30
入口湍流强度/%0.5
水力直径/m2.496
压力出口/Pa1.01×105
出口湍流强度/%5
水力直径/m2.496
地面边界滑移壁面
车身壁面固定壁面
其余壁面对称壁面

Fig.15

PIV experiment site diagram"

Fig.16

Velocity flow charts of CFD simulation and velocity flow charts of wind tunnel experiment"

Fig.17

Velocity cloud images of CFD simulation and velocity cloud images of wind tunnel experiment"

1 胡兴军,李腾飞,王靖宇,等.尾板对重型载货汽车尾部流场的影响[J].吉林大学学报:工学版,2013,43(3): 595-601.
Hu Xing-jun, Li Teng-fei, Wang Jing-yu, et al. Numerical simulation of the influence of rear-end panels on the wake flow field of a heavy-duty truck[J]. Journal of Jilin University(Engineering and Technology Edition), 2013, 43(3): 595-601.
2 杨永柏, 王靖宇, 胡兴军, 等. 皮卡车外流场的数值模拟[J]. 吉林大学学报: 工学版, 2007, 37(6): 1236-1241.
Yang Yong-bai, Wang Jing-yu, Hu Xing-jun, et al. Numerical simulation on flow field around pickup trucks[J]. Journal of Jilin University(Engineering and Technology Edition), 2007, 37(6): 1236-1241.
3 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.
4 Aljure D E, Calafell J, Baez A, et al. Flow over a realistic car model: wall modeled large eddy simulations assessment and unsteady effects[J]. Journal of Wind Engineering and Industrial Aerodynamics, 2018, 174: 225-240.
5 Ekman P, Venning J, Virdung T, et al. Importance of sub-grid scale modeling for accurate aerodynamic simulations[J]. Journal of Fluids Engineering, 2021, 143(1): 011501.
6 谷正气,赵万东,张勇,等.网格质量评价指标对汽车外流场模拟结果影响的研究[J].汽车工程,2015,37(11): 1265-1269.
Gu Zheng-qi, Zhao Wan-dong, Zhang Yong,et al. A research on the effects of mesh quality evaluation criteria on the results of vehicle external flow field simulation[J].Automotive Engineering, 2015, 37(11): 1265-1269.
7 Peng W, Ji W X. Surface mesh quality improvement by weighted inscribed circle method[J]. Advances in Engineering Software: Including Computing Systems in Engineering, 2019, 136: 102693.
8 熊超强,臧孟炎,范秦寅.低阻力汽车外流场的数值模拟及其误差分析[J].汽车工程,2012,34(1):36-39, 45.
Xiong Chao-qiang, Zang Meng-yan, Fan Qin-yin.Numerical simulation of external flow field around low drag car and its error analysis[J]. Automotive Engineering, 2012, 34(1): 36-39, 45.
9 Fabritius B, Tabor G. Improving the quality of finite volume meshes through genetic optimisation[J]. Engineering with Computers, 2016, 32(3): 425-440.
10 Choi J H, Kim H, Sastry S P, et al. A deviation-based dynamic vertex reordering technique for 2d mesh quality improvement[J]. Symmetry, 2019, 11(7): 11070895.
11 Huang L L, Zhao G Q, Wang Z L, et al. Adaptive hexahedral mesh generation and regeneration using an improved grid-based method[J]. Advances in Engineering Software: Including Computing Systems in Engineering, 2016, 102: 49-70.
12 Sun L, Zhao G Q, Ma X W. Quality improvement methods for hexahedral element meshes adaptively generated using grid-based algorithm[J]. International Journal for Numerical Methods in Engineering, 2012, 89(6): 726-761.
13 Xiao L, Yang G X, Zhao K Y, et al. Efficient parallel algorithms for 3D Laplacian smoothing on the GPU[J]. Applied Sciences-Basel, 2019, 9(24): 9245437.
14 Li W H. 3D mesh smoothing method based on vertex classification and distance equalization[C]∥5th International Conference on Systems and Informatics,Nanjing, China, 2018: 906-910.
15 Huang Z J, Ding J M, Xiang S Y. Suspension footbridge form-finding with laplacian smoothing algorithm[J]. International Journal of Steel Structures, 2020, 20(6): 1989-1995.
16 Zhou T, Shimada K. An angle-based approach to two-dimensional mesh smoothing[J/OL]. [2021-05-23]. .
17 房征. 四边形网格拓扑优化方法的研究[D].山东:山东大学材料科学与工程学院,2019.
Fang Zheng. Research on topological optimization method of quadrilateral mesh[D]. Shandong: School of Materials Science and Engineering, Shandong University, 2019.
18 汪怡平,谷正气,邓亚东,等.基于准k-ε-v~2/LES模型的汽车外流场数值模拟[J].机械工程学报,2012,48(14):97-103.
Wang Yi-ping, Gu Zheng-qi, Deng Ya-dong,et al.Aerodynamic simulations of vehicle by using the hybrid semi k-ε-v~2/LES model[J]. Journal of Mechanical Engineering, 2012, 48(14): 97-103.
19 张海峰. 基于湍流模型的汽车气动特性研究[D]. 长沙: 湖南大学机械与运载工程学院, 2011.
Zhang Hai-feng. Analysis of vehicle aerodynamics performance base on turbulent model[D]. Changsha: College of Mechanical and Vehicle Engineering,Hunan University, 2011.
20 张勇,石佳琦,谷正气,等.尾部特征参数对气动阻力交互影响与全局优化研究[J].湖南大学学报:自然科学版,2020,47(2):14-20.
Zhang Yong, Shi Jia-qi, Gu Zheng-qi, et al. Study on interaction influence of tail characteristic parameters on aerodynamic drag and global optimization[J]. Journal of Hunan University(Natural Sciences),2020, 47(2): 14-20.
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