Aerodynamic noise characteristics of airfoils with morphed trailing edges

Abstract

Numerical investigation of the aerodynamic and aeroacoustic characteristics of a symmetrical NACA 0012 airfoil developed by National Advisory Committee for Aeronautics (NACA) with a conventional hinged flap and a morphed flap has been carried out. The unsteady flow characteristics over the airfoil surface and at the airfoil wake are captured using high-fidelity Large Eddy Simulations. The tests were carried out for a freestream velocity of U∞=20 m/s, corresponding to a chord-based Reynolds number of Rc=2×105, at angles of attack α=0° and 4°. The results of the airfoil static pressure distribution show that the airfoil with morphed trailing edge produces higher values of lift coefficient than the airfoil with hinged trailing edge due to its higher suction peak resulting in larger pressure difference between the suction and pressure sides. Furthermore, from the wake-flow measurements, boundary-layer analysis, wall-pressure spectra, space–time correlation, it is concluded that the Morphed airfoil produces higher values of surface pressure fluctuations near the trailing edge which extend farther into the wake of the trailing edge compared to the Hinged airfoil. Consequently, the increased pressure fluctuations at the vicinity of the trailing edge results in a higher values of radiated far-field noise for the airfoil with morphed trailing edge flap.