Study of the Aerodynamic Characteristics and Interaction Noise of Airfoil with Porous Leading Edges Based on the Rod-Airfoil Model

To investigate the suppression effect of porous materials on turbulence interference noise at the leading edge of airfoils and reveal the mechanism of noise reduction, numerical simulations of the classic rod-airfoil (NACA0012) interaction noise model were conducted using Large Eddy Simulation (LES) combined with the FW-H acoustic analogy method. The calculation was validated by comparison with experimental data and grid sensitivity analysis. The study compared the flow field and sound field characteristics of a solid leading edge with porous leading edges with porosities of 40%, 50%, and 60%, respectively. The results showed that porous leading edges can effectively reduce the single-tone noise of the low- and mid-frequencies. The noise reduction effects increase with the porosity. A maximum noise reduction up to 11.2 dB was obtained, but the averaged drag also increases accordingly. Analyses of the pressure fluctuations, velocity distribution in the stagnation region, and turbulence coherence were also carried out. The results showed that the porous medium suppressed the vertical velocity component \nu ' of the incoming flow when it impinges on the leading edge, so the pressure fluctuations p' is suppressed meanwhile. Secondly, the porous structure disrupted the spanwise coherence of the turbulence structure, reducing the efficiency of sound radiation.