Pickup trucks offer operators the advantage of towing payload capacity, but at higher operating costs in terms of fuel usage. Some of the increased fuel usage can be attributed to the shape of the truck, which is not aerodynamically advantageous, especially when compared to the other vehicles. This analysis reviews the air flow patterns around a truck during highway travel and uses computational fluid dynamics (CFD) modeling to analyze the best method to predict drag coefficient for the truck. This paper investigates the various mesh features available and the physics models that can be used to approximate the fluid flow, determining the significance of each numerical method. The results indicated that a polyhedral mesh with an incompressible fluid assumption, solved using a segregated flow solver and Reynolds Averaged Navier Stokes k-ε equations provided a suitable balance between accuracy and computational investment when compared to other turbulence models or physics modeling solvers. Further, the analysis investigated the impact on drag of driving the truck with the bed tailgate in the raised, closed position versus driving with the bed tailgate lowered in the open position. The findings actually show that the truck drag coefficient is reduced by about 3% when the truck is operated with the tailgate in the lowered, open position.

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