Study of compressible effects and reduced frequency effect on pitching wing performance in Mars environment

The Martian atmosphere significantly affects the aerodynamic characteristics of its aircraft. In this study, static analysis of a wing with National Advisory Committee for Aeronautics (NACA) 0012 airfoil is conducted in a low-pressure wind tunnel simulating Martian conditions. Additionally, large eddy simulation is employed to investigate the pitching aerodynamic characteristics of the wing at a Reynolds number of 8000. The effects of incoming Mach number (0.05-0.9) and reduced frequency (0.25-2.0) on aerodynamic performance and flow characteristics are analyzed. To further explore the underlying flow physics, dynamic mode decomposition (DMD) and proper orthogonal decomposition (POD) are utilized. The results indicate that increasing the incoming Mach number has opposite effects on lift coefficient hysteresis and flow separation in subsonic and supersonic regimes. The drag coefficient generally increases with Mach number, with a significant rise due to shock wave formation. Furthermore, both low and high reduced frequencies enhance the hysteresis of the lift and momentum coefficients, while drag coefficient hysteresis increases with reduced frequency. Flow separation is also influenced by reduced frequency. DMD analysis reveals that as Mach number increases, the dominant flow pattern shifts from pressure fluctuations near the leading edge to fluctuations near the trailing edge and wake region. POD analysis indicates that as the reduced frequency increases, pressure fluctuations on the wing surface intensify.