Journal of Bionic Engineering ›› 2020, Vol. 17 ›› Issue (3): 539-552.doi: 10.1007/s42235-020-0043-2
Modification of Flow Structure and Sound Source by Hybrid Porous-serrated Trailing Edge
Hanru Liu1,2,3*, Nanshu Chen1, Yangang Wang1, Zhijie Hu1,2,3
- 1. School of Power and Energy, Northwestern Polytechnical University, Xi’an 710072, China
2. Research & Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen 518057, China
3. Key Laboratory of Aerodynamic Noise Control, Mianyang 621000, China
Modification of Flow Structure and Sound Source by Hybrid Porous-serrated Trailing Edge
Hanru Liu1,2,3*, Nanshu Chen1, Yangang Wang1, Zhijie Hu1,2,3#br#
- 1. School of Power and Energy, Northwestern Polytechnical University, Xi’an 710072, China
2. Research & Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen 518057, China
3. Key Laboratory of Aerodynamic Noise Control, Mianyang 621000, China
摘要： The effects of hybrid porous-serrated trailing edge on flow structure and sound source of NACA65(12)-10 at moderate Reynolds number (Rec = 5 × 105) have been investigated by Delayed Detached Eddy Simulation (DDES). Compared with conventional serrated trailing edge, the pressure fluctuation in the vicinity of hybrid porous-serrated trailing edge is further decreased significantly. The typical necklace vortex structures stretching across adjacent serrations are suppressed by the porous additive. It is found that porous media changes the shear stress distribution along the serration edge and inside the serration gap, which consequently eliminates the generation of necklace vortex. Therefore, the deformation of vortex tube caused by velocity vector is weakened. The underlying mechanisms associated to the sound source modification are analyzed based on vortex sound theory. The magnitude of Lamb vector and the angle between
vorticity and velocity vectors are synchronously reduced by the porous additive, which implies that the present hybrid porous-serrated trailing edge has important influence on the further attenuation of far-field aerodynamic noise.