Wall-modeled large-eddy simulation and direct numerical simulation of broadband trailing edge noise from a naca 0012 airfoil

We examine the capability of wall-modeled large-eddy simulation (WMLES) approach to predict the broadband noise generated by a NACA 0012 airfoil. The simulations are carried out for the Mach 0.12 uniform flow over a NACA 0012 airfoil at zero degree angle of attack with a chord-based Reynolds number of 408,000. To examine the influence of the grid resolution on aerodynamic and aeroacoustic quantities, we perform WMLES calculations for three different grid resolutions. In addition to the experimental and wall-resolved large-eddy simulations available for this flow, we also perform a direct numerical simulation (DNS) for an additional reference dataset to benchmark the WMLES performance. In all of our simulations, surface roughness is used near the leading edge to trip the boundary layer. Comparisons indicate that all of the WMLES cases provide a good approximation of the skin friction coefficient. However, other quantities, such as the mean velocity profile, are sensitive to the grid resolution. Sensitivity to the grid is greater for two–point (or two–time) quantities, such as the pressure fluctuation correlation. Some of the observed differences are associated with the tripping and transition mechanism, which is itself significantly affected by the grid resolution. The importance of WMLES outer grid resolution in capturing the relevant turbulent flow length and time scales is discussed.