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Optimization of the Realizable k - ε Turbulence Model Especially for the Simulation of Road Vehicle
Technical Paper
2012-01-0778
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Realizable k-ε turbulence model has been used widely for engineering development. In this turbulence model, the default values of empirical coefficients such as C₂, σk and σε are obtained from some particular experiments. They are a good choice for most simulations-though may be not the best choice for simulating the aerodynamic characteristics of road vehicle. In order to improve the accuracy of simulation, a set of new empirical coefficients should be designed especially for simulating the aerodynamic characteristics of road vehicle. These empirical coefficients are found out by DoE (design of experiments) in this paper. Firstly the value range of empirical coefficients is decided by the laws that the aerodynamic force coefficients change with altering of empirical coefficients. Secondly 20 sets of empirical coefficients are obtained randomly by applying optimal Latin Hypercube method in Isight. After that the aerodynamic characteristics of MIRA model is simulated with these coefficients in Fluent. On that basis, Kriging model is used to establish approximation model. Regarding the results from wind tunnel experiments as the optimization objective, the empirical coefficients which are more suitable for simulating the aerodynamic characteristics of road vehicle are found out by applying Multi-island Genetic Algorithm. Finally, the new empirical coefficients are applied for the development of a real road vehicle, and its advantages are verified by the wind tunnel test. The results show that, by using the new empirical coefficients, the drag coefficient error is decreased by 2.5%, and the relative error of lift coefficient is reduced by 0.01 with faster convergence rate. However, the velocity contour around the rear of the MIRA model is not improved significantly compared with the velocity contour from PIV test.
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Citation
Gu, Z., Song, X., Jiang, Y., and Gong, X., "Optimization of the Realizable k - ε Turbulence Model Especially for the Simulation of Road Vehicle," SAE Technical Paper 2012-01-0778, 2012, https://doi.org/10.4271/2012-01-0778.Also In
References
- GU, Z Q. Automotive aerodynamics [M] China Communications Press 2005
- Wang, F J. Analysis of computational fluid dynamics-CFD software principle and application Beijing Tsinghua University Press 2004
- Ahmed, S. Ramm, G. Faltin, G. “Some Salient Features Of The Time-Averaged Ground Vehicle Wake,” SAE Technical Paper 840300 1984 10.4271/840300
- Chen, K. Design and Analysis of experiments[M] Beijing Tsinghua University Press 2005
- Queipo, Nestor V. Haftka, Raphael T. Shyy, Wei Goel, Tushar Vaidyanathan, Rajkumar Tucker, P. Kevin Surrogate- based Analysis and Optimization [J] Aerospace Sciences 2005 41 1 28
- Chen, Hong Ooka, Ryozo Kato, Shinsuke Study on Optimum Design Method for Pleasant Outdoor Thermal Environment Using Genetic Algorithms and Coupled Simulation of Convection, Radiation and Conduction [J] Building and Environment 2008 43 1 18 31
- Lasher, William C. Sonnenmeier, James R. An Analysis of Practical RANS Simulations for Spinnaker Aerodynamics Journal of Wind Engineering and Industrial Aerodynamics 96 2008 143 165
- Deage, P. Gabriel, A. Lindbichler, G. et al. Efficient Use of Computational Fluid Dynamics for the Aerodynamic Development Process in the Automotive Industry 26 th AIAA Applied Aerodynamics Conference Honolulu, Hawaii 18 21 August 2008
- Closed-Test-Section Wind Tunnel Blockage Corrections for Road Vehicles Society of Automotive Engineers, Inc. 1996
- Hong, C. Ryozo, O. Shinsuke, K. “Study on Optimum Design Method for Pleasant Outdoor Thermal Environment using Genetic Algorithms(GA) and Coupled Simulation of Convection, Radiation and Conduction,” Building and Environment 43 18 30 2008 10,1016/j.buildenv.2006.11.039