CFD Investigation of a Novel Fuel-Saving Device for Articulated Tractor-Trailer Combinations

Enhancing the aerodynamic efficiency of commercial vehicles is gaining increasing importance as it helps to reduce both overall fuel consumption as well as emissions. This paper investigates the advantages offered by a novel fuel-saving device for such vehicles. This device uses a moving surface to impart additional kinetic energy to flow near the roof surface. The additional momentum in the flow modifies the flow field, thereby significantly reducing pressure drag. Distribution of drag shows that the front and rear faces of the semitrailer and the tractor cab are the dominant contributors to drag. The overall reduction in drag has been quantified by the distribution of pressure on the surface as well as the individual contribution to drag by each surface of the vehicle. The newly developed device has been shown to be very effective in reducing the fuel consumption of tractor-trailers.