Large eddy simulation of active flow control for aerodynamic drag reduction in vehicle platooning

Mitigating global climate change requires reducing carbon emissions, with the transportation sector playing a pivotal role. Vehicle platooning offers significant potential for energy savings and emission reduction. However, traditional passive flow control strategies for reducing aerodynamic drag—such as vehicle spacing and shape optimization—face challenges, including high costs, real-world implementation difficulties, and vulnerability to external factors like crosswinds. These limitations highlight a gap in current platooning methods. This study investigates the use of zero-mass active flow control technologies to address these challenges. Through numerical simulations and experimental validation, the aerodynamic performance of a 1:3 scaled 25° Ahmed body is examined. Large eddy simulation is employed for simulations, and wind tunnel experiments were conducted at the Shanghai Automotive Wind Tunnel Center. The results show that active flow control significantly reduces drag, with the drag coefficient (Cd) of a single body decreasing from 0.33 to 0.20, resulting in a 35.4% drag reduction. In a two-vehicle platoon, applying active flow control to both vehicles achieves a 40.6% control efficiency, surpassing that of passive flow control. Additionally, active flow control stabilizes the flow field, reduces flow fluctuations, and improves shear layer dynamics between vehicles. This study provides novel insights into integrating active flow control into vehicle platooning, offering an effective solution to the limitations of traditional methods. By improving aerodynamic efficiency, this approach contributes to reducing energy consumption and advancing sustainable transportation.