Master thesis and internship[BR]- Master's thesis : Aerodynamic performances of a fairing in paragliding[BR]- Internship

Abstract

This thesis investigates the aerodynamic performance of a fairing designed for paragliding, focusing on drag reduction to enhance flight efficiency. The research combines experimental and computational methods to evaluate the fairing's impact on overall aerodynamic behavior. Initially, full-scale wind tunnel tests identified key flow behaviors such as stagnation points and recirculation zones. Subsequently, experiments were conducted on a reduced model to quantify aerodynamic forces, including drag and side forces, across various Reynolds numbers and yaw angles. These experimental results were complemented by Computational Fluid Dynamics (CFD) simulations using advanced turbulence models, namely k − ω SST and γ − Reθ. The γ − Reθ model, which provided results closer to experimental data, was chosen for subsequent simulations. The good agreement between numerical and experimental results validated the CFD model. Main finding is that the fairing effectively reduces the drag of the pilot. Wake analysis revealed recirculation zones that induce side forces, which the pilot must consider to prevent unwanted rotation of the fairing. An upscaling study confirmed that aerodynamic coefficients remain consistent with increasing Reynolds number, with a maximum difference of 5%, deemed acceptable. Further analysis of inner airflow was performed by closing the fairing's openings. Results showed improved drag coefficients for yaw angles ranging from -5° to 5°, while higher yaw angles led to increased forces. Finally, 2D RANS simulations of NACA 0012, 0015, 0018, 0021, and 0024 airfoils were conducted to determine optimal aerodynamic performance. The three thickest airfoils, NACA 0018, 0021, and 0024, were found to offer the best aerodynamic performance, resulting in a good basis for future works.