On aerodynamic drag reduction of road vehicles in platoon

With stringent requirements on fuel economy and greenhouse gas emissions, we are facing a challenge to reduce road vehicle aerodynamic drags. While travelling in a platoon, the wake of preceding vehicle can affect the aerodynamic characteristics of following vehicle. Due to platoon airflow field, the drag of each vehicle changes, posing impact on vehicle's fuel consumption. In the study, the Motor Industry Research Association (MIRA) car models, namely notchback, fastback, and squareback, are generated. The airflow fields for isolated single-vehicle models are imitated by computational fluid dynamics (CFD) simulation. The drag coefficient errors between simulation and experiment are less than 6%, indicating good agreement between the simulation and wind tunnel test. Using CFD simulation, we explore the effects on aerodynamic properties of vehicles in platoon due to contributing factors of nonuniform inter-vehicle separation distance, number of vehicles, and vehicle shapes. Insightful findings from the study will provide guidelines for developing autonomous vehicle platoons.