Numerical Study of Aeroacoustic Control with Bionics Airfoil for Aircraft

By applying the LBM-LES method, the aerodynamic noise sound field is directly calculated for the porous bionic airfoil constructed based on the bionics principle, and the flow characteristics and acoustic properties of porous bionic airfoils are analyzed in depth, and the effects of flow resistance and length of porous media on the control effect of bionic airfoils are discussed in detail. It is revealed that the bionic airfoil has a better noise reduction effect when the length of the porous medium is 20% and the flow resistance is high. When the flow resistance keeps relatively low, the wake vortex of the bionic airfoil will become stronger, and an orderly Karman vortex street is formed after falling off from the trailing edge of the airfoil, which will enhance the aerodynamic noise of the bionic airfoil and lose the noise reduction effect. The coherent structure in the boundary layer near the airfoil wall and the wake vortex shedding at the airfoil trailing edge are the main sound sources of far-field aerodynamic noise. The noise control of the bionic airfoil needs to comprehensively consider the influence of the two main sound sources in order to effectively reduce the aerodynamic noise.