Fig. 30 illustrates the two most dominant components of high - performance aircraft noise at afterburner.They are the
low-frequency large turbulence structures noise and the new noise component at higher frequency.This figure includes
noise spectra measured from 1101 to 1501 inlet angle at 101 intervals. It shows that at 1101, the level of the large turbulence structures noise is lower than that of the new noise component. But as the inlet angle increases, the SPL of the large turbulence structures noise increases rapidly. This noise component attain sits maximum intensity at around 1401. Its level drops off by 10 dB when the inlet angle increases further to 1501. On the other hand,the new noise component increases in intensity starting from approximately 1001. Its intensity peaks around 1151 and decays rapidly as the inlet angle increases