Relationship between noise sources spatial distribution and radiation characteristic of airfoil trailing edge

The relationship between the airfoil turbulent boundary layer trailing edge noise spatial distribution and radiation characteristic was studied in detail. A Reynolds averaged Navier-Stokes (RANS) based airfoil trailing edge noise prediction method was employed to investigate the NACA 0012 airfoil turbulent boundary layer trailing edge noise source spatial distribution and radiation characteristic at four different operating conditions. The spatial distribution of NACA 0012 airfoil turbulent boundary layer trailing edge noise source at different frequencies was calculated firstly. It indicated that the turbulence within boundary layer was responsible for the airfoil turbulent boundary layer noise. Meanwhile the source region approached to the trailing edge of airfoil with increase of the noise frequency; it was also shown that the spatial dimension of source and the strength of the source increased first and then decreased with the increase of frequency; meanwhile, the noise radiation characteristic from different source regions in boundary layer was computed secondly. It demonstrated that the noise from source region in boundary inner layer was concentrated on high frequency and the boundary outer layer was responsible for the low frequency of noise. The noise energy moved to low frequency with increase of angle of attack or decrease of incoming flow velocity.