Aerodynamic optimization of a vehicle platoon equipped with vortex generators based on RSM-NSGA-II

To address the limitations of traditional isolated aerodynamic control strategies in multi-vehicle platooning, this paper proposes a hybrid control method that synergistically integrates vehicle platooning with passive vortex generators (VGs). Taking a 1:1 scale MIRA notchback sedan platoon consisting of three vehicles as the research object, a multi-objective multivariable joint optimization was performed to minimize the individual aerodynamic drag coefficients (Cd) of the lead, middle, and trailing vehicles concurrently. Using the Box-Behnken response surface methodology (RSM) combined with the NSGA-II genetic algorithm, the two normalized inter-vehicle spacings ( x 1 / L , x 2 / L ) and the total number of roof-mounted VGs were specified as the design variables. The results demonstrate that the VGs successfully suppress flow separation over the rear window and tailgate sections by injecting high-momentum freestream flow into the low-momentum boundary layer. Ultimately, the Pareto-optimal configuration parameters for aerodynamic drag reduction within safe operational limits were obtained, and the synergistic drag-reduction mechanism involving platoon wake interactions and boundary layer intervention was elucidated.