Aiming at the problem of evolution law of fluctuating pressure signal under unsteady flow characteristics in cavity

a multi-domain analysis method for fluctuating pressure signal is presented. Firstly

the optimal expression of time/frequency sound pressure level for fluctuating pressure signal is obtained. According to the time series alignment and the spatial position of the measuring point

the sound pressure level spatial distribution map is formed. Then the optimal expression of the time/frequency sound pressure level is analyzed by time series correlation

and the time-varying law of the sound pressure level in the cavity is obtained. The simulation results of multi-domain analysis show that the maximum relative error between the optimal expression of time/frequency energy and the theoretical value is 0. 880 %

and the relative error of time series correlation analysis is 0. 900 %. The results of multi-domain analysis of a cavity experiment in a two-meter high-speed wind tunnel show that the pseudo-period of diffusion and contraction of the sound pressure level from the back wall to the leading edge of the cavity is approximately 0. 127s in Ma = 2. 0. This method can reveal the time-varying law of the sound pressure level in different positions of the cavity

and has great engineering application value.