Experimental investigation of flat plate self-noise reduction using trailing edge serrations

Abstract

This paper presents an experimental study on the noise reduction potential of sawtooth trailing edge serrations at low-to-moderate Reynolds number (1.6 x 105 < Rec < 4.2 x 105, based on chord). The noise radiated by flat plates with both straight and serrated trailing edges has been measured in an anechoic wind tunnel at the University of Adelaide. The trailing edge serrations were found to reduce narrowband noise levels by up to 13 dB. The straight and serrated trailing edge far-field acoustic spectra are scaled according to existing theory and compared to predictions of trailing edge noise obtained using current semi-empirical methods. In addition, velocity spectra measured in the trailing edge near wake region using hot-wire anemometry are related to the far-field noise measurements to give further insight into the serration noise reduction mechanism.