Numerical Iterative Analysis of Drag Reduction System for a Racing Car Rear Wing

Abstract

In Formula Student competitions, the active adaptation of the aerodynamic components to the current race track conditions can significantly enhance the overall dynamic performance of the car. Due to the abundant low-speed corners, angles of attack of fixed aerodynamic components are usually exaggerated, preventing the car from achieving higher acceleration capabilities due to induced drag. This issue can be tackled by introducing an active drag reduction system (DRS). In this work, a strategy for performing iterative numerical simulations is proposed, with the goal of obtaining a range of different configurations suitable for certain track conditions. Specifically, the case of lowest drag is exploited.

Different macros were developed to couple the utilization of computational fluid dynamics tools for aerodynamic analysis with an extensive iterative process with minimal user interference. An initial mesh refinement study was conducted. Afterward, angles of attack and centers of rotation of the two most rear flaps are iterated. The lowest-drag configuration was found to be at α_flap1 = 0° and α_flap2 = −6 ° , the latter mostly due to its aerodynamic interaction with the rest of the system. Results show that the angle of attack of flap 2 had the most influence on the overall forces, while varying the centers of rotation had a weaker impact. Nevertheless, combining the investigation of the angles of the attack with the center of rotation yields optimal DRS configuration with the minimum drag. Within one loop of the proposed strategy, a reduction of up to 94.5% in rear-wing drag was found. The strategy proposed can be looped until a configuration is obtained for specific optimization targets, such as drag reduction.