Aerodynamic optimization of car top box design for drag reduction using CFD and Kriging modeling

In this paper, the influence of the shape parameters and position parameters of the car top box on the aerodynamic performance is studied. The flow field numerical simulation software STAR-CCM+ was used to conduct CFD simulation of the vehicle outflow field. Through comparative analysis, it was found that the contribution rate of the top box to the resistance coefficient of the vehicle was 10.39%, which proved the necessity of drag reduction optimization of the top box. Based on Isight optimization platform and aiming at reducing drag, the shape parameters and position parameters of the top box were optimized. The Kriging agent model is used to optimize the drag coefficient, and the post-processing diagrams of the outflow field before and after optimization are compared and analyzed, and the drag reduction mechanism is summarized. In addition, on the basis of the optimized vehicle model, the drag reduction slot is added to the bottom of the roof box, and the drag reduction is finally achieved by 5.2%. The aerodynamic drag reduction of the top box can enhance the power performance and fuel economy of the vehicle and reduce carbon emissions.