Experimental Aerodynamic Characterization of a Multi-Element Formula Student Rear Wing using Particle Image Velocimetry

Formula Student competitions require vehicles to operate at relatively low Reynolds numbers while generating maximum downforce to improve cornering speeds. This necessitates the use of aggressive high-lift devices, often resulting in complex flow phenomena such as steep pressure gradients, wake interactions, and potential flow separation. This work presents a detailed experimental investigation of the aerodynamic performance of a multi-element rear wing assembly designed for a Formula Student racing car. The experiments were conducted at the wind tunnel facilities of the National Institute for Aerospace Technology (INTA). A high-resolution Particle Image Velocimetry (PIV) system was employed to quantify the flow field around the suction side of the main plane and the interaction with the flap elements. The study focuses on the analysis of the velocity vector fields and scalar maps obtained at different spanwise locations. The PIV measurements effectively captured the boundary layer development and the flow turning efficiency of the multi-element setup. Particular attention is given to the flow physics within the gaps between elements and the near-wake region. The experimental results reveal the presence of a coherent recirculation bubble at the trailing edge of the second flap (as seen in the instantaneous and average velocity maps), highlighting the limit of flow attachment in high-angle-of-attack configurations. Furthermore, the PIV data provides a quantitative assessment of the velocity deficit in the wake, offering a robust dataset for the validation of Computational Fluid Dynamics (CFD) simulations typically used in the design phase of these vehicles. The visualization of the streamlines and turbulent structures demonstrates the capability of the PIV setup to resolve flow features critical for optimizing the aerodynamic performances in competitive motorsport applications.