Turbulence-airfoil interaction noise reduction using wavy leading edge: an experimental and numerical study

Cyril Polacsek (1) , Gabriel Reboul (2, 1) , Vincent Clair (2, 1) , Thomas Le Garrec (1) , Guillaume Dufour (3) , Hugues Deniau (3)

1 ONERA - The French Aerospace Lab [Châtillon]
2 LMFA - Laboratoire de Mecanique des Fluides et d'Acoustique
3 CERFACS - Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique

Passive treatments aiming at reducing turbofan broadband noise have been recently studied in the framework of European Project FLOCON. A concept based on a sinusoidal variation of the leading edge of a single airfoil aiming at reducing interaction noise has been investigated by ONERA. Turbulence-airfoil interaction mechanism is achieved using a turbulence grid located upstream of a NACA airfoil tested in ISVR anechoic open wind tunnel. High noise reductions are obtained (3-4 dB) for all studied flow speeds. Moreover, aerodynamic performances are shown to be slightly increased by the treatment that tends to reduce the drag without modify the mean loading. Experimental work is supplemented by numerical simulations using Large Eddy Simulations (LES) and direct Euler approaches to predict the acoustic response of the wing. LES is chained to a FWH (Ffowcs-Williams and Hawkings) integral to assess the radiated field. Isentropic turbulence is synthetically injected by means of a suited inflow boundary condition. Present computations are focused on the reference case (without treatment). Numerical predictions are compared to the experiment, and to analytical solutions issued from Amiet theory.

Domaines: Acoustique [physics.class-ph]

Cyril Polacsek, Gabriel Reboul, Vincent Clair, Thomas Le Garrec, Guillaume Dufour, et al.. Turbulence-airfoil interaction noise reduction using wavy leading edge: an experimental and numerical study. 18th International Congress on Sound & Vibration, 2011, Rio de Janeiro, Brazil. ⟨hal-02086038⟩