Investigating the effect of SGS models in the LES method on the shape of eddies and calculating the emitted sound by implementing the Ffowcs Williams–Hawkings equation

Subgrid models are employed to predict the effect of small eddies in the LES method, and their performance is important in calculating the Reynolds stress and transferring the kinetic energy of turbulence to the grid. In this paper, the effect of sub-grid scale models in the LES method on the calculation of aerodynamic sound is investigated. For this purpose, five different sub-grid scale models including Smagorinsky-Lilly, WMLES, WMLES S-Omega, WALE, and KET have been used. First, the statistical convergence of computational methods has been investigated by employing aerodynamic coefficients, and the WMLES S-Omega model has been discarded due to aerodynamic instability. The near-wall flow study reveals models’ differences in the prediction of separation location and length-scale of vortices, which has changed the flow pattern. Aeroacoustic results obtained for the sound pressure level in the one-third octave band are validated using experimental data for the Naca-0012 3D airfoil. Based on the obtained results, the WALE model has presented the best approximation among different models in terms of the amount and trend of sound changes in different frequencies.