Abstract:
Inspired by the silent flight of owl,the special curved serration structure of the owl’s feather was applied to the edge of triangular serration,and an airfoil with curved serration trailing edge was designed. Meanwhile,the potential noise reduction effect of the bionic curved serration structure was investigated. The large eddy simulation(LES)and the FW-H acoustic analogy method were conducted to analyze the aeroacoustic characteristic between the NACA0018 prototype airfoil,the bionic curved serration airfoil and the triangular serration airfoil. The simulation results reveale that the overall sound pressure levels of the bionic curved serration airfoil decreases at all azimuth angles of the sound direction distribution. Compared with the traditional triangular serration airfoil,the maximum value of noise reduction of the bionic curved serration airfoil is 3.77 dB. The results of pressure pulsation cloud map and flow direction velocity turbulent wave distribution show that the bionic curved serration structure is beneficial to suppress the pressure fluctuation adjacent to the trailing edge and decrease the turbulent fluctuation at the middle region of the serration significantly,and thus reduce the aerodynamic noise of the airfoil with curved serration.