Numerical Investigation of Riblets on Rod-Airfoil Interaction Noise

Turbulence interaction noise is widely present in the aviation field. In order to adapt the increasingly stringent airworthiness noise standards, new noise reduction measures must be explored to break through the noise reduction bottleneck. The large eddy simulation and FW-H equation were used to study the influences of three riblets on the rod-airfoil interaction noise. The riblet reduces the wall shear stress on the surface of the rod, delays the flow separation of the boundary layer, and breaks the large-scale vortex structure after the rod has fallen off into small-scale vortex structures, thereby reducing RMS velocity and spanwise vorticity intensity of the wake. The stability of the downstream airfoil and the surrounding flow field is improved, and RMS pressure fluctuation is reduced, thus the interaction noise of the rod-airfoil is decreased. D15 can drop the tonal noise of rod by 21.35 dB and airfoil noise by 10.57 dB.