Predicting the high-angle-of-attack characteristics of an airfoil for micro/unmanned aerial vehicle applications

This study investigates the aerodynamic characteristics of a low-Reynolds-number airfoil at high angles of attack (AoA) from 0° to 90°, focusing on their relevance for micro and unmanned aerial vehicle (MAV/UAV) applications. Simulations are conducted using the k-ω shear stress transport (SST) turbulence model using ANSYS Fluent software. Among the key findings is that the lift coefficient CL increases from 1.2981 at 0° AoA to a peak of 2.034 at 11° before decreasing to 1.51 at 90°, indicating initial lift improvement followed by a reduction due to potential flow separation or stall. The drag coefficient CD increases from 0.0222 at 0° AoA to a peak of 0.3572 at 12°, and then decreases to 0.0467 at 90°, indicating initially increasing turbulence and separation, followed by stabilization in the flow regime. The lift-to-drag ratio L/D reaches its maximum of 32.334 at 90° AoA, highlighting improved aerodynamic efficiency at higher AoAs despite increased drag. The skin friction coefficient Cf shows a maximum of 0.046 918 at the leading edge at 30° AoA and 0.039 426 2 at the trailing edge at 90°, indicating critical points of frictional drag. Additionally, the turbulence viscosity ratio at the LE peaks at 0.5586 at 30° AoA and drops to 0.004 at 90°, while it increases at the trailing edge, reaching 0.039 426 2 at 90°, showing heightened turbulence effects at high AoAs. The present numerical study, however, determines the lift coefficient to be 2.00. This yields a maximum percentage variation of 11.5% compared with the value in the literature. These results provide a comprehensive overview of how high-AoA conditions impact aerodynamic performance, offering valuable insights for optimizing airfoil design and improving MAV/UAV efficiency.