Noise pollution is a critical issue in urban and industrial areas, particularly those near airports. This study experimentally investigated brush and serration edge treatments as passive methods to control wake-leading-edge interaction noise in a tandem symmetric airfoil configuration using surface-mounted unsteady pressure sensors in a subsonic wind tunnel. Surface pressure fluctuations, a key source of aerodynamic noise, were examined on the rear airfoil surface at a relatively low angle of attack and a Reynolds number of 185,000. The results demonstrate that the brush increases the surface pressure fluctuation power spectral density (PSD) levels at low frequencies, whereas its performance at medium and high frequencies varies depending on the relative positioning of the airfoils. The highest PSD reduction (up to 5.5 dB) was achieved when the downstream airfoil leading-edge was aligned with the upstream airfoil chord line. In contrast, the serration performs satisfactorily at low frequencies for negative vertical distances between the rear airfoil leading-edge and the front airfoil trailing-edge (yg < 0); however, its effectiveness is minimal for positive distances, except when the rear airfoil leading-edge aligns with the front airfoil chord line, where it performs optimally. Although serration can sometimes increase PSD levels, it generally reduces pressure fluctuations over a broader frequency range than the brush. Both treatments can be effective for wake-leading-edge interaction noise control, particularly in configurations where the downstream airfoil leading-edge aligns with the upstream airfoil chord line, providing valuable insights for mitigating aerodynamic noise in practical applications

Keywords