Influence of Wind Tunnel Walls on Flow Dynamics over Test Objects

Abstract

This thesis develops a robust computational framework for correcting wind tunnel wall interference to align experimental data with free-air conditions. Utilizing a potential flow approach, the study transitions from the Method of Images to a more versatile Panel Method to enforce no-penetration boundary conditions across complex geometries. A vortex-based wall model was selected for its high analytical replicability, while the Vortex Panel Method (VPM) was implemented for body modeling due to its superior accuracy in satisfying the Kutta condition for both lifting and non- lifting airfoils. Validation using NACA 0012 and NACA 2412 profiles demonstrated excellent agreement between VPM simulations and experimental datasets. The results assert that panel-based singularity methods serve as a high-fidelity substitute for experimental data in interference modeling. This research establishes a critical foundation for real-time interference correction in aerodynamic testing. Transitioning toward real-world application, the Wall Signature Method was utilized to recon- struct model geometries from pressure orifices, providing direct insights into blockage factors and lift corrections. Furthermore, the analysis was extended into the compressible regime (M > 0.7) using the Prandtl-Glauert transformation and Ackeret’s theory, assuming a thermally perfect gas. The lift-curve slope dCL/dα and drag coefficient CD were evaluated across the full subsonic-to- supersonic Mach range for the NACA 0012 section, demonstrating that wall interference amplifies as 1/√1−M^2. The wall correction factor κ was computed from experimental tunnel data and shown to follow the Prandtl-Glauert scaling, confirming that the same geometric blockage induces progressively larger aerodynamic interference at higher Mach numbers. Future work is proposed to integrate viscous boundary layer effects and dissipative drag equations to further refine the convergence between numerical simulations and experimental flight data.