Improvement of airfoil turbulent trailing-edge noise semi-empirical prediction formulation

The traditional BPM semi-empirical prediction airfoil turbulent boundary layer trailing edge noise was improved. The traditional BPM semi-empirical prediction formulation overpredicts the spectra in high frequency range at high angle of attack or for thick airfoil. It is found that it was mainly caused by the overestimation of the noise contribution from pressure side source through the analysis and comparison between the traditional BPM semi-empirical prediction formulation and Howe's trailing-edge noise theoretical model. Then the ratio of noise contribution from suction side and pressure side source is improved to the square power of boundary displacement thickness rather than the one power appeared in the traditional BPM semi-empirical prediction formulation. The improved BPM semi-empirical prediction formulation is employed in the airfoil turbulent boundary layer trailing-edge noise prediction, which shows that better results can be obtained from the improved BPM semi-empirical prediction formulation for NACA0012 airfoil at high angle of attack. The prediction for wind turbine airfoil DU-96-W-180 is improved significantly by improved BPM semi-empirical prediction formulation.