Fundamental Screech Tone Analysis of Elliptic Pipe Jet

The elliptic pipe jet screech is explored at a pressure ratio from 2 to 6. The pipe length to diameter ratio is 5. The fundamental screech frequency and magnitude are obtained from the sound pressure level spectrum. The screech frequency decreases as the pressure ratio increases. The minor plane has more tones than the major plane at an emission angle of 75 degrees from the jet axis. The amplitude of the screech differs among the planes. The amplitude is higher at lower emission angles from 45 to 75 degrees and lower at a sideline angle of 90 degrees.