NUMERICAL STUDY OF THE WAVY LEADING-EDGE NOISE REDUCTION IN ROD-AIRFOIL INTERACTION WITH SPECTRAL DIFFERENCE METHOD

Inspired by the leading-edge tubercles on humpback whales’ flippers, the wavy leading-edge of the airfoil offer a promising approach to reduce interaction noise. In this study the rod-airfoil interaction noise is computed with a high order spectral difference solver. NACA 0012 airfoils with straight and wavy leading edges(WLE) are simulated to study the effect of wavy leading edges on rod-airfoil interaction noise. The velocity distribution around the airfoil and the noise spectra at far-field are compared with the experimental data and a good agreement is obtained. By comparing the contributions of the noise sources at the straight and wavy leading edges to the far field, it is found that the WLE significantly reduces the sound pressure level of the tonal noise and changes its far field directivity. It also reduces the SPL of broadband components in some frequency bands. The correlation analysis of the wall pressure at the leading edge shows that the WLE reduces the intensity of the noise source at the leading edge, which manifests as a source cut-off effect.