| The radiation sound power of the underwater sound sources is an important parameter to evaluate the acoustic characteristic of sound sources,and the radiation impedance is an important factor to influence the radiation sound power of sound sources.There are still some problems in the existing measurement methods,for example,the low-frequency absorption performance limits the free-field measurement method,and the low acoustic mode density at low frequencies limits the reverberation method.By means of analytical calculation,numerical calculation and experimental measurement,this paper has established a numerical prediction model for calculating acoustic radiation in tanks.The established numerical method can be used to analyze the influencing factors of acoustic radiation characteristics,so as to better understand the acoustic mechanism of sound source in underwater radiation and to provide theoretical basis for measuring method of medium and low frequency of sound sources in tanks.A multi-physical field modeling method is established in this paper for studying the acoustic radiation characteristics of underwater sound sources in tanks.The accuracy of the numerical model is verified by analytical method.The effect of sound source t emission locations and different volume ratio of sound field and sound source on the radiation characteristics of sound sources in the tank is analyzed.When the sound source frequency is lower than the limit frequency and close to the modal frequency of the sound field,the radiation resistance and the radiated sound power at different locations are different and different from the free field.When the vibration of sound source at different positions tends to be the same,the difference of radiation resistance and radiated sound power is very small and similar to the free field.When the size of the sound source is not negligible,the sound source itself becomes a boundary of the sound field and the influence of sound source radiation characteristics on the sound field need to considered.The numerical calculation of the acoustic radiation characteristics of the cylindrical shell sound source in the tank show that,in addition to the natural frequencies of the cylindrical shell and the mode frequencies of the sound field,the radiation resistance and radiation sound power have little change.Finally,combined with the problem of large uncertainty in low-frequency measurement of the non-anechoic tank comparison method,the applicability of the comparison method is analyzed from the perspective of the influence mechanism of the sound field boundary of the tank on the structure-acoustic coupling and experimental measurements are carried out to verify the theoretical analysis.This paper provides an effective analysis method for studying the acoustic radiation characteristics of underwater structures in non-anechoic tanks. |
