Vortex, Acoustic Interference

In order to better understand mechanism of vortex and sound interaction, great efforts have been made to improve grid generation techniques and numerical methods for aeroacoustic predicting. Major achievements in present thesis included below aspects:1. Smooth, body fitted grids, such as ONERA M6 wing and slender body, were generated by solving elliptic equation with Hilgenstock source item modification. Based on the grid generation techniques and TFI method, A deforming grid techniques was applied to investigate the acoustic characteristic of an oscillating airfoil. The deforming grid was set up into a multi-block framework.2. In order to investigate blunt body trailing vortex sound emission characteristic, NACA0012 trailing vortex sound was simulated with LES model, and FW-H equation was applied to obtain trailing edge tone noise.3. Supersonic jet flow structure was analyzed at different work condition. Based on FW-H equation and LES model, under expanded supersonic jet noise was simulated.4. LES model was applied to simulate two dimensional vortex merging process. The process of vortex merging was divided into four stages: (1) quasi-stability stage, (2) convective stage, (3) diffusion stage, (4) merging stably stage. The distance between two vortex cores at different time stage and was also given. The acoustic characteristic during merging process was analyzed.