Screech Suppression of Supersonic Jet Noise

Screech tones are a common by-product of supersonic jets. The screech tones are seen to get amplified due to the effect of solid surfaces. The amplification is clearly seen in V/STOL aircrafts and in particular during landing. Different techniques have been applied to reduce and/or eliminate the screech tones altogether. A detailed test programme was conducted to evaluate the noise generating potential of supersonic jets. Screech tone removal was one subset of the test programme conducted at the at the National Research Council Canada's Acoustic Reverberant Chamber in Ottawa. The results of the measurement programme are presented in this paper. In particular, the results of two techniques utilized for screech removal will be the focus of the presentation.