CFD Analysis on Aerodynamic Drag Reduction of Pickup Vehicles Using Rear Spoiler

Abstract

Global warming and environmental pollution have recently been threatening factors for our survival. The prime concern of automotive industry is to reduce the fuel consumption of the vehicle for the sake of saving energy, thereby conserving the environment. Improving the performance of the engine, reducing the mass of the vehicle and reducing the resistance of aerodynamic drag are some of the recent options used for improving fuel economy. A large chunk of the fuel used is employed in overcoming the aerodynamic drag at highway speeds and therefore if reduced could produce a large reduction in the total fuel consumption and minimize the negative environmental effects. In this work, air flow over a pickup vehicle with spoiler attached on the rear end of the vehicle roof at different inclination angles and spoiler length using computational fluid dynamics (CFD) with the objective of reducing the aerodynamic drag was studied. All numerical simulations were performed using commercial CFD software Fluent and realizable k-epsilon turbulence modeling at different vehicle speeds. A 1/12 scaled down generic pickup model with extended cab modeled with SolidWorks was used as the baseline model. Improvement in drag coefficient was obtained in models with spoiler when compared to the baseline model without any add-on device. A drag reduction of 6.50, 6.12 and 0.493% was achieved on model one, model three and model two, respectively, when compared to the baseline model. The decrease in the amount of drag was attributed to the decrease in wake region and swirling air inside the bed box of the pickup vehicle. Because of the reduction in drag, a maximum of 3.90% reduction in fuel consumption was achieved. Overall aerodynamic drag reduction of pickup vehicle using spoiler as an add-on device which leads to better fuel economy was shown here.