Numerical investigation of airfoil self-noise reduction by addition of trailing-edge serrations

Abstract

DNS of the flow around a NACA-0012 airfoil are conducted, employing an immersed boundary method to represent flat-plate trailing-edge extensions both with and without serrations. Properties of the turbulent boundary layer convecting over the trailing-edge are similar for all cases. For cases with serrations, the trailing-edge noise produced by the flow over the airfoil is observed to decrease in amplitude, and the frequency interval over which the noise reduction occurs differs depending on the serration length. The trailing-edge noise appears otherwise largely unaffected by the serrations in terms of its directivity and spanwise coherence. The hydrodynamic behaviour in the vicinity of the t..