Academic Analysis And Experimental Study Of Impulsive Noise In Firing-gas Jet Field Of Rocket

In this dissertation, academic analysis of impulsive noise in firing-gas jet field of rocket has been researched as well as experimental study. Nonlinar acoustics is applied on impulsive noise in firing-gas jet field of rocket. There are some deficiencies put forward in traditional FFT transform, and wavelet analysis is applied on the signal of impulsive noise in firing-gas jet field of rocket. The frequency bands of turbulence noise and initial shock wave noise are separated by using frequency band energy spectrum based on wavelet coefficient. The filter method of automatic soft-threshold based on optimization wavelet-package is applied on the filtering of signal of impulsive noise in firing-gas jet field of rocket.Finally, the relevant noise attenuator has been designed on the basis of above experimental methods, results, conclusions and analysis technology, identified by experiments.lt is also validated to be effective of decreasing shock wave noise by using frequency band energy spectrum based on wavelet coefficient.