Computation of aerodynamic noise for rod wake-airfoil interactions

Aerodynamic noise from the rod wake-airfoil interactions at M=0.2 and Re_D=46,000 is computed by solving the linearized perturbed compressible equations (LPCE), with the acoustic source and hydrodynamic flow variables computed from the incompressible LES. A 2D LPCE calculation is conducted at zero spanwise wave-number (k_z=0) with an assumption of statistical homogeneity in the spanwise direction. Then, a 2D Kirchhoff method is used to extrapolate the sound field at the acoustic far-field boundary (40D) up to the microphone location (185D away from the airfoil chord center). Finally, a power spectrum density (PSD) for actual span (30D) is predicted by Oberais correction method for 3D spectral acoustic pressure and spanwise coherence function for the wall pressure. The computational results for flow and acoustics are critically validated with the experimental data measured at the Ecole Centrale de Lyon