Aeroacoustic Investigation of Beveled Trailing Edges by High-Speed Particle Image Velocimetry

Abstract

The aerodynamic noise generated by trailing edge of aircraft wings at take-o_ and approach con_guration continues to be a critical factor in the future development of aviation. Trailing edge noise is also a serious concern for wind turbines, marine propellers, helicopter rotors, axial and centrifugal turbines and compressors. A fundamental understanding of how the energy contained in turbulent motions around trailing edges is converted to sound will be bene_cial for designing silent airfoils and control surfaces. Current research aims at applying new tools of ow _eld interrogation i.e. high-speed planar and tomographic PIV to the canonical problem of trailing edge noise. In analytical models, the far _eld noise can be described using turbulent quantities like the spanwise coherence. The use of high-speed tomographic PIV creates a link between the phenomenological description of the ow and acoustic _eld in terms of coherence of structures and noise. The geometric con_guration used involves an airfoil with an elliptic leading edge and an asymmetric beveled trailing edge with 25 deg tip angle (_) and three di_erent radii of curvature (R). The measurements are taken at four di_erent Reynolds numbers.