Numerical Investigation of NACA 64A-204 Airfoil Performance at Subsonic and Supersonic Regimes

This study presents a numerical investigation of the aerodynamic performance of the NACA 64A-204 airfoil under subsonic (Mach 0.8) and supersonic (Mach 1.5) conditions using two-dimensional CFD simulations in ANSYS Fluent. A steady-state RANS approach with the SST k–ω turbulence model and a validated C-type grid was employed to capture shock waves, boundary layer separation, and adverse pressure gradients with high accuracy. Simulations were conducted over a wide angle-of-attack range (0°–50°), covering both attached-flow and deep-stall conditions. Results reveal clear differences between regimes: while the airfoil sustains attached flow at moderate angles in subsonic conditions, supersonic flows generate strong oblique shocks, earlier separation, and reduced aerodynamic efficiency. The analysis highlights maximum lift and efficiency trends, Mach-dependent drag rise, and flow structure transitions. These findings provide not only detailed aerodynamic insights into the NACA 64A-204 but also practical implications for high-speed aircraft design, offering a CFD-based reference for performance assessment, future experimental wind tunnel validation, and the development of drag-mitigation or flow-control strategies.