A grid-less time domain method for plate trailing edge noise prediction

A grid-less time domain method for predicting trailing edge noise radiated from a two-dimensional flat plate is established in the present study, which is based on the discrete vortex method and vortex sound theory. The trailing edge noise is calculated in a decoupling manner. Firstly, the shear layer shed from the plate trailing edge is simulated through a discrete vortex method, and the key parameters of the vortices are obtained, including the strengths, positions and velocities. Then, a sound radiation model of the vortices in the free space is deduced in the frame of the vortex sound theory. Besides, to account for the influence of the plate surface, a time domain boundary element method is introduced. After that, the sound pressure distribution and the far field directivity radiated from the trailing edge vortices are analyzed. The present results indicate that the vortex clouds rolled up by point vortices are typically dipole sources, and the scattering effect from the plate surface can not only enhance the sound pressure level but also lead the maximum sound pressure to propagate in the vertical direction to the surface. This grid-less model depicted here simulates the flow and sound field simultaneously, which can help to improve the basic understanding on the trailing edge noise radiation and provide a reliable method for noise investigation with engineering importance as well. © 2015, Press of Chinese Journal of Aeronautics. All right reserved.