Assessment of Drag Reduction Devices Mounted on a Simplified ‎Tractor-Trailer Truck Model

Aerodynamic drag reduction of tractortrailer combination trucks is critically important to improve their fuel consumption which consequently results in lower emissions. One practical method to reduce aerodynamic drag of a truck is by mounting drag reduction devices on the truck. This paper presents a numerical study of turbulent flow over a simplified tractortrailer truck with different drag reduction devices mounted on the truck using the Reynolds Averaged NavierStokes (RANS) approach to assess the effectiveness of those devices in drag reduction around the tractortrailer gap region. Three cases with different drag reduction devices have been studied and significant drag reduction (above 30%) has been achieved for all three cases. Detailed analysis of the flow field has been carried out to understand drag reduction mechanisms, and it shows that no matter what drag reduction devices are deployed the drag reduction is mainly due to the reduced pressure on the front face of the trailer, and a small proportion of the drag reduction is due to the reduced turbulent kinetic energy in the gap region.