Trailing-edge noise prediction using the nonlinear disturbance equations

Direct computation of broadband noise in reasonable computational times is possible if the calculations can be focused in a specific noise making region of interest. Turbulent boundary layer trailing edge (TBL-TE) noise is of special research interest in the wind turbine aeroacoustic community because, in large scale applications, broadband noise can propagate relatively large distances. A new computational aeroacoustic method is proposed which solves the Nonlinear Disturbance Equations (NLDE) in refined time and spatial scales surrounding the trailing edge of airfoil blades. PSU-WOPWOP uses the NLDE solution to propagate the acoustic solution to observers. A new NLDE flow solver is presented with validation cases. The Blade Systems Design Study (BSDS) atback airfoil section and a NACA 0012 airfoil are tested. Noise is generated due to unsteady laminar vortex shedding and boundary layer interaction, but no TBL-TE noise has been predicted yet. Turbulence injection techniques still have to be introduced that allow for the direct computation of TBL-TE noise. For the NLDE tool to be effective in TBL-TE noise prediction, turbulence must be injected at the inflow of the trailing edge computational domain.