CFD analysis of heterogeneous and homogeneous multi-truck platoon aerodynamic drag reduction

The purpose of this study was to provide an analysis of the aerodynamic phenomena involved with the platooning of multiple truck-trailer configurations. With fuel usage being a large factor in high operational costs of truck fleets, increases in fuel economy may drastically reduce these costs for large fleets. Furthermore, there are clear linkages between aerodynamic drag on a particular vehicle and that vehicle’s fuel economy, providing incentive to decrease drag and thus decrease fuel usage. This is increasingly being achieved by the platooning of multiple vehicles coupled with a controller to govern engine usage and preserve proper separation distance between vehicles. Computational Fluid Dynamics (CFD) provides a relatively inexpensive and robust avenue for investigating drag reduction. Previous studies of these heavy vehicles have primarily focused either on single vehicle drag reduction or platoons involving two identical truck-trailer configurations. This study investigated more complex truck-trailer configurations where trailer loads were not necessarily homogeneous and therefore the wake structure behind each vehicle was somewhat unique. Modifications to lateral offset and intra-platoon separation distance in the case of homogeneous configurations, and platoon order in the case of heterogeneous configurations were all studied for their effect on platoon drag reduction. It was determined that lateral offset had a fairly significant effect on drag reduction, and platoon benefits were also incredibly sensitive to intra-platoon separation distance variation. Some effects noted in these scenarios were also present in the heterogeneous scenarios, and suggestions for platoon orders and general separation distance trends are presented.