Flat plate self-noise reduction at low-to-moderate Reynolds number with trailing edge serrations

摘要

This paper explores the noise reduction potential of sawtooth trailing edge serrations on a flat plate at low-to-moderate Reynolds number. The noise radiated by a flat plate with both sharp and serrated trailing edges has been measured in an anechoic wind tunnel at the University of Adelaide. The noise measurements have been taken at a range of flow speeds (Reynolds numbers of Re_c < 4.5 x 10~5, based on chord) for two different sawtooth geometries. Trailing edge serrations are found to achieve an average attenuation of up to 7 dB over a certain Strouhal number range, where Strouhal number is St = fδ/U_∞,fs frequency, δ is boundary layer thickness and U_∞ is the free stream velocity. The results of this study are compared with theoretical noise reduction predictions showing that significant differences exist between measurements and theory.