Transient Underwater Sound Source Sound Energy Calculation And Measurement Method Research

As the “light” sound source in underwater acoustic detection,underwater explosion sound's source level standardization will guide the selection of equivalent weight of explosive.Underwater explosion sound is a kind of broadband underwater transient acoustic.And establishing accurate transient acoustic measuring method and measuring means is the key point of deeply studying the characteristics of underwater explosion.Most of the existing underwater transient noise research focus on researching acoustic field measurement and calculation in the free field,or use field quantity such as sound pressure level to assess a transient noise.But there are too many uncertain environment factors in external field which make the measurement repeatability and accuracy poor.Underwater explosion sound source is a kind of broadband underwater transient acoustic,establishing accurate transient acoustic measuring method and measuring method,which is a key link in the process of deeply studying the characteristics of underwater explosion.Existing underwater transient noise research,mainly concentrated in the free field(outside field)of acoustic field measurement and calculation,the use of sound pressure level for such a field is transient noise assessment,but the field environment influenced by many uncertain environment factors,make the sound pressure level measurement repeatability is poor,directly affect the measurement accuracy.And external force and some relative measurement environment,the noise elimination pool has good repeatability,measuring environment easy to satisfy,measurement of high efficiency,low cost advantage,and is widely applied to the quantitative measurement of all kinds of sound source acoustic properties.In this paper,in the steady-state sound source free-field pool measurement method based on the proposed a reverberation tool measuring methods for the acoustic characteristics of transient,by measuring the transient acoustic sound energy has been further equivalent acoustic of the transient sound power.Proposed method applies to both frequency domain and time domain analysis,power spectrum analysis draws on steady state transfer function for the correction methods of sound field;Time domain analysis of autocorrelation function is used to collect the transient sound energy density,equivalent acoustic power is obtained.This paper based on the free field to study the transient acoustic field.Then compared to the steady state sound,we analyze the influencing factors of transient acoustic field characteristics in a closed space and the sound field of closed space,and then puts forward the enclosed space measuring method of the transient sound radiation sound power.Furthermore,we use COMSOL to simulate the different frequencies and pulse widths CW pulse in free field and the closed space.Then we simulated the underwater TNT explosion pressure field by using AUTODYN,and used the results as sound source to simulate the sound field by using COMSOL.According to the simulation results of free field and the closed space,we found that the simulation has high accuracy and verified the proposed method of measuring transient acoustic sound power.Finally we measured the sound power of CW pulse and electric spark explosion in anechoic poll,non-anechoic pool and the glass tank.The results showed that the experiment has good repeatability and accuracy,and verified the proposed method of measuring transient acoustic energy in closed space well.