Title: Study on the effect of window opening on the drag characteristics of a car

Authors: Jaffar Syed Mohamed Ali; Syed Muhammad Kashif; Mohd Sultan Ibrahim Shaik Dawood; Ashraf Ali Omar

Addresses: Department of Mechanical Engineering, Faculty of Engineering, International Islamic University Malaysia, P.O. Box 10, 50728, Kuala Lumpur, Malaysia ' Department of Mechanical Engineering, Faculty of Engineering, International Islamic University Malaysia, P.O. Box 10, 50728, Kuala Lumpur, Malaysia ' Department of Mechanical Engineering, Faculty of Engineering, International Islamic University Malaysia, P.O. Box 10, 50728, Kuala Lumpur, Malaysia ' Department of Mechanical Engineering, Faculty of Engineering, International Islamic University Malaysia, P.O. Box 10, 50728, Kuala Lumpur, Malaysia

Abstract: In this study, the effect of window opening on the drag characteristics of a car is investigated. This additional aerodynamic drag can considerably affect the performance of a car in terms of instability, noise and fuel consumption. Using a 3D car model, the effect of window opening on the drag characteristics was numerically studied using STAR-CCM+ commercial CFD software. It was observed that the aerodynamic drag is highly influenced by the different window openings. For validation, a scaled down car model was tested in the IIUM low speed wind tunnel. The results obtained from both simulation and experimental data showed that the car with all windows open produced higher drag than a car with all windows closed. The experimental data from the wind tunnel test results was found to be in good agreement with the simulation counterpart for the determination of drag coefficient for both window positions.

Keywords: aerodynamic drag; computational fluid dynamics; CFD; STAR-CCM+; wind tunnels; vehicle modelling; vehicle testing; window opening; automotive windows; 3D modelling; open windows; closed windows; drag coefficient.

DOI: 10.1504/IJVSMT.2014.066502

International Journal of Vehicle Systems Modelling and Testing, 2014 Vol.9 No.3/4, pp.311 - 320

Available online: 23 Dec 2014 *

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