前缘下垂远场低频宽频噪声特性

An experimental study on the far-field noise characteristics of leading-edge droop nose is conducted in Beihang University D5 wind tunnel. The computational fluid dynamics method is used to obtain the flow information near the high-lift device. A two-dimensional high-lift configuration model with a leading-edge droop nose is used, and the trailing-edge flap is stowed to eliminate the flap noise interference. The results show that broadband noise dominates the far-field noise spectrum of the high-lift configuration with a leading-edge droop nose. With the increase of freestream velocity, the broadband amplitude increases gradually. Among that, the amplitude of the low frequency (200-400 Hz) broadband noise is well-matched after normalization by the 5 Mach number power law. With the increase of angle of attack, the mid to high frequency broadband noise does not significantly change, but the amplitude of low frequency broadband noise changes significantly that first decreases and then increases. The analyses of the effect of effective windward area, DSM cloth deformation and their combined effects on the far-field noise amplitude at different angles of attack find that the amplitude variation of the low frequency broadband noise is related to the flow characteristics near the model.