Numerical simulation of aerodynamics of coupled flapping-pitching airfoil with trailing-edge flap

Navier-Stokes equations were numerically solved with Reynolds averaged Spalart-Allmaras turbulence model in order to analyze the effects of coupled flapping-pitching oscillation on the unsteady aerodynamics and dynamic stall characteristics of an airfoil with active trailing-edge flap (TEF) at high speed forward flight. Results show that compared to simple pitching airfoil with TEF, when flapping oscillating with same frequency and phase is added, higher overshoot of aerodynamic coefficients and larger hysteresis loops are observed. Coupled oscillation increases area of viscous interaction resulting in deep dynamic stall instead of light dynamic stall. Coupled oscillation increases the sensitivity of pitching moment coefficient on flow-field variation.