AbstractsTransportation

Environmental regulations and high fuel prices are of increasing importance for manufacturers of heavy duty vehicles. The main issue is to increase the efficiency of the trucks and to reduce the fuel consumption. When driving on the highway more than 40% of the total energy is lost to aerodynamic drag. This increases the importance of the aerodynamic drag behavior of trucks in developing sustainable transport. This research develops insight in the aerodynamic drag performance of a platoon and the influence of tails on the platoon. To study this problem, a platoon of simplified truck models with rear drag reduction devices is simulated using a CFD program. Different simulations are done where the spacing between trucks is varied, as well as the tail plate angle and the body front rounding. Equipping trucks with tails in a platoon at short spacings leads to an increased drag of trucks directly behind a tail due to the pressure increase by the tail and the inwards deflected streamlines. At short spacings the best way is to only equip the last body with a tail so the streamlines can follow the contours of the platoon and the wake is reduced by the tail. At larger spacings the bodies behave like the isolated bodies but with some minor influence of the wake of the preceding bodies. So at larger spacings the bodies with the lowest drag in isolation are favored. The configuration with tails on all bodies is thus favored. This research shows that equipping trucks with tails in a platoon can definitely be beneficial, but it depends on the spacing between the bodies in a platoon. The best configuration is to drive at the smallest spacing as possible and equip the last body with a tail, so the wake of the platoon is reduced. Since the best configuration of the platoon depends on the spacing, there is another possibility which is to create an automated folding and deploying system to adapt the configuration of the platoon to the spacing between the bodies.