Simulation Study on Vehicle Drag Reduction by Surface Dimples
Automotive designers have been trying to use dimples to reduce drag in vehicles. In this work, a car model has been applied with dimple surface with a parameter called dimple ratio DR, the ratio between the depths of the half dimple over the print diameter of the dimple, has been introduced and numerically simulated via k-ε turbulence model to study the aerodynamics performance with the increasing depth of the dimples The Ahmed body car model with 25 degree slant angle is simulated with the DR of 0.05, 0.2, 0.3 0.4 and 0.5 at Reynolds number of 176387 based on the frontal area of the car model. The geometry of dimple changes the kinematics and dynamics of flow. Complex interaction between the turbulent fluctuating flow and the mean flow escalates the turbulence quantities. The maximum level of turbulent kinetic energy occurs at DR = 0.4. It can be concluded that the dimples have generated extra turbulence energy at the surface and as a result, the application of dimples manages to reduce the drag coefficient of the car model compared to the model with smooth surface.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1112193Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1767
 D. Srivastav, Flow control over airfoils using different shaped dimples, International Conference on Fluid Dynamics and Thermodynamics Technologies, (2012) 92–97, Singapore: IACSIT Press.
 L.-m Tian, L.-q Ren, Q.-p Liu, Z.-w Han, X, Jiang, The mechanism of drag reduction around bodies of revolution using bionic non-smooth surfaces, Journal of Bionic Engineering, (2007) 109-116.
 Dol, S.S., Azimov, U. & Martinuzzi, R.J.M. (2012). Statistical description in the turbulent near wake of rotating circular cylinder. World Academy of Science, Engineering and Technology 72, 505 – 509.
 L. Hermann, B. Michael, K. Cagatay, Drag Reduction by dimples? A Complementary Experimental/Numerical Investigation, International Journal of Heat and Fluid Flow, 29(3), (2008) 783-791.
 S.R. Ahmed, G. Ramm, G. Faltin, Some salient features of the times-averaged ground vehicle wake, SAE Society of Automotive Eng., Inc, 1(840300) (1984) 1–31.
 C.K. Chear, S.S. Dol, Vehicle Aerodynamics: Drag Reduction by Surface Dimples? International Journal of Mechanical, Aerospace, Industrial and Mechatronics Engineering 9(1) (2015), 202-205.