Numerical Study on the Wall Pressure Fluctuations of Airfoils with Straight and Serrated Trailing Edges

Trailing-edge noise is an important noise source for applications involving rotating blades such as unmanned aerial vehicles. To reduce trailing-edge noise, serrations are widely used. A recent study showed that relaxing the frozen turbulence assumption can significantly improve the noise prediction accuracy for serrated trailing edges. In this work, we further investigate the statistical characteristics of wall pressure fluctuations using NACA-0012 airfoils with straight and serrated trailing edges. Incompressible wall-modelled large eddy simulations are conducted at 0° and 10° angles of attack. The instantaneous and mean flow statistics are in good agreement with experimental measurements. The power spectral density and streamwise frequency-dependent correlation length of the wall pressure fluctuations near the trailing-edge serrations are examined. It is found that the two characteristics at different streamwise positions on the serration vary slightly in the mid- and high-frequency range at 0° angle of attack. At 10° angle of attack, the power spectral density on the suction side and pressure side near the trailing edge differ significantly. The upstream and downstream frequency-dependent correlation lengths vary slightly with the streamwise position on the same side of the serration.