Time-frequency Analysis of Test Data from Complex Noise of Rocket Engine Jet

In order to predict characteristics of high-thrust rocket launching noise, a sub-scale solid engine was chosen for experiment. The wavelet transform and FFT methods were used in processing experimental noise data, the following results can be found out: the low-frequency and high-amplitude shock components are found in the engine's working time, and their amplitude and frequency are very different from classic jet broadband noise; The filtered noise spectrum is typical turbulent broadband noise spectrum, and the sound efficiency of jet noise is 0.51%, which is in good agreement with empirical data of rocket launching, so it can be concluded that shock noise is not a part of jet noise.