Flow characteristics of a pickup truck with regard to the bed geometry variation

The bed is one of the most important parts of a pickup truck for aerodynamic performance. The flow characteristics of a pickup truck were examined in a series of wind tunnel experiments and numerical simulations with regard to the bed geometry variation, the bed length, and the bed height. The drag coefficient was changed in accordance with the bed geometry variation so that the bed length and bed height had a significant interaction effect. The main factors that affected the drag coefficient were the bed recirculation flow over the bed and the reverse flow in the wake. The drag coefficient increased when the downwash of the bed flow was not recirculated into the bed but was attached to the upper part of the tailgate. The larger reverse flow in the wake and the enlarged adverse pressure area inside the bed influenced the drag increment when there was no attachment of the bed flow. For a low-drag pickup truck, the bed should be designed such that the bed flow is not attached to the tailgate and the reverse flow in the wake is small.