Skin Friction Coefficient and Boundary Layer Trend on UKM Aster i-Bond


Article Preview

This study concerns with aerodynamic drag on a passenger car. By using computational fluid dynamics (CFD) method, we found that values of skin friction coefficients for three different parts of the car: front, top and rear parts, are different. This study addresses three different basic possible flows around a car: favourable, zero and adverse pressure gradients. Generally, cars use approximately 20% of their engine power to overcome aerodynamic drag, which is generally proportional to the frontal area. The boundary layer at each position has been analyzed to ascertain the effect of wall shear stress on the car surface. It is found that the value of wall shear stress velocity is highest at the rear part, followed by front and top parts. Subsequently, it is shown that the front part has the thinnest viscous region despite not being the part with the highest local ambient velocity compared with the top and rear parts. Despite its supposed aerodynamic shape, the rear part of the car sees separation of flow and the total drag per unit area here is the largest, twice as large as front part and more than seven times larger than the top part.



Edited by:

R. Varatharajoo, F.I. Romli, K.A. Ahmad, D.L. Majid and F. Mustapha




Z. Harun et al., "Skin Friction Coefficient and Boundary Layer Trend on UKM Aster i-Bond", Applied Mechanics and Materials, Vol. 629, pp. 450-455, 2014

Online since:

October 2014




* - Corresponding Author

[1] F. M. White, Viscous fluid flow, 2ndEdn. ed.: McGraw Hill, (1991).

[2] Z. Harun, J. P. Monty, R. Mathis and I. Marusic, Pressure gradient effects on the large-scale structure of turbulent boundary layers, J. of Fluid Mechanics, vol. 715, pp.477-498, (2013).

[3] R. E. M. Nasir, F. Mohamad, R. Kasiran, M. S. Adenan, M. M. Faizal, M. H. Mat and A. R. A. Ghani, Aerodynamics of ARTec's PEC 2011EMoC Car, International Symposium on Robotics and Intelligent Sensors (2012).


[4] R. K. Hanna, CFD in Sport - a Retrospective; 1992 -2012, 9thConference of the International Sports Engineering Association (ISEA), (2012).

[5] N. E. Ahmad, E. Abo-Serie and A. Gaylard, Mesh Optimization for Ground Vehicle Aerodynamics, CFD Letters, ISSR Journals, vol. 2, pp.54-65, (2010).

[6] M. A. Brown, A. J. Baxendale and D. Hickman, Recent Enhancements of the MIRA Model Wind Tunnel, 2ndMIRA International Conference on Vehicle Aerodynamics, Coventry, (1998).

[7] R. Singh, Automated Aerodynamic Design Optimization Process for Automotive Vehicle, SAE Technical Paper, (2003).


[8] M. Tsubokura, T. Kobayashi, T. Nakashima, T. Nouzawa, T. Nakamura, H. Zhang, K. Onishi and N. Oshima, Computational visualization of unsteady flow around vehicles using high performance computing, Computers& Fluids, vol. 38, p.981–990, (2009).

[9] Z. Harun, J. P. Monty and I. Marusic, Constant adverse pressure gradient turbulent boundary layers, 17thAustralasian Fluid Mechanics Conference, Auckland, New Zealand, (2010).

[10] M. Koike, T. Nagayoshi and Hamamoto, Research on aerodynamic drag reduction by vortex generators, Mitsubishi Motor Technical Review, Mitsubishi Motor, (2004).