Noise Attenuation by Half Flat tip Serrated Trailing Edge in Rotating Blades

Abstract

Two rotating blade models with different half-flat tip trailing edge serrations were proposed. The flow characteristics and aerodynamic noise were simulated using the large-eddy simulation model and Ffowcs Williams and Hawking’s acoustic analogy, respectively. The effect of half-flat tip trailing edge serrations in reducing noise was investigated. Results showed that the proposed half-flat tip trailing edge serration designs can effectively reduce broadband noise, and the effectiveness of noise reduction was related to the wavelength-to-amplitude ratio of the half-flat tip trailing edge serrations. The Wide-serrated blade had better noise reduction performance, and the local noise reduction according to the simulations can be as high as 3.3 dBA. Besides, it was found that the aerodynamic performance of the rotating blades was not detrimentally affected by the introduction of half-flat tip serration.