Aerodynamic Drag Reduction of Commercial Ground Vehicles Using Numerical Techniques

Automobiles of today warrants improved aerodynamic behaviour that results in low drag producing vehicles. Such optimally designed vehicles offer advantages such as better overall performance, desirable driveability, rapid response, improved stability and added fuel economy. In this paper, an attempt is made to accomplish lower drag coefficient by incorporating the dimples shape on the vehicle roof surface. Aerodynamic flow analysis was conducted with and without dimple shape effect on a bus truck trailer and commercial vehicles, using ANSYS Fluent software tool. Effect of different sized and shaped dimples on aerodynamic performance was analysed as well. Results obtained were validated with available literature and it is found that coefficient of drag obtained showed less than 10 % error. It was found that drag values were significantly reduced with dimple effect on both the commercial vehicles. Both models demonstrated that the fluid flowing on the surface did not separate from the vehicle roof, and the vortex size at the back was reduced. Further paper gives a detailed study of various parameters like turbulence model effect, pressure distribution on the vehicles, temperature and mach number variations. This study is proposed to enhance energy efficiency of the automobiles as better aerodynamics improves their mileage and fuel economy.