Effect of underbody structure on aerodynamic drag and optimization

• Published in: Journal of Measurements in Engineering Vol. 5; no. 3; pp. 194 - 204
• Main Authors: Yuan, Zhiqun, Wang, Yiping
• Format: Journal Article
• Language: English
• Published: Kaunas JVE International Ltd 01.09.2017
• Subjects: Aerodynamic characteristics; Aerodynamic drag; Aerodynamics; Design; Drag coefficients; Drag reduction; Mathematical models; Optimization; Spoilers; Underbodies; Wind tunnel testing; Wind tunnels
• ISSN: 2335-2124; 2424-4635
• DOI: 10.21595/jme.2017.19210

The numerical simulation and wind tunnel experiment are employed to investigate the aerodynamic characteristics of automobile. The object is to investigate the sensibility of aerodynamic characteristic to the underbody, and summarize the influence of aerodynamic attachments on the aerodynamic drag, which can provide more useful date as a reference to underbody design of automobile. In the wind tunnel experiments, the aerodynamic drag of automobile with simplified flat underbody is measured. The realizable k - ε model is employed to compute the aerodynamic drag. The computational results show a good agreement with the experimental date, which proving the accuracy of the numerical calculation method. Then the numerical calculation model with real underbody structure is established on this basis. Calculation results show that there are many separation vortexes in the automotive underbody and with a great influence on the aerodynamic characteristics, which is the main reason for the formation of aerodynamic drag and make the aerodynamic drag increased by 23.4 %. In order to reduce drag, A kind of wheel spoiler and three kinds of underbody spoiler are designed, and the influence of the key parameters on aerodynamic drag is analyzed, which both had effective influence for reducing aerodynamic drag, and the largest drop of drag coefficient are 4.86 % and 7.05 % with the reasonable structure designs. The results of calculation and analysis can give suggestion for vehicle designing.