Research On Scattering Characteristics Of Underwater Targets With Sound-absorbing Coverin

It is an important means to reduce the strength of submarine target and improve the stealth performance by laying resonator acoustic covering layer on the surface of submarine,which can not only avoid the detection of enemy active sonar,but also isolate the self-noise radiation and vibration.Therefore,it is of great theoretical and practical value to study the scattering characteristics of complex targets with acoustic overlay.This paper mainly studies the acoustic scattering characteristics of complex targets with cavity acoustic absorbing overlay.The specific work is as follows:A finite element model for calculating and analyzing the acoustic overlay under oblique incidence is established.Based on the uniform solid overlay,the finite element model is compared with the calculation junction of transfer matrix method to verify the accuracy of the finite element model.The acoustic performance of the cavity acoustic absorption overlay under oblique incidence is calculated,and the reflection coefficient of the cavity acoustic overlay required for the subsequent acoustic scattering analysis is obtained.Based on the non-rigid plate element method,the target strength of the complex target with the sound absorbing overlay is calculated.Taking the rigid sphere with the cylindrical cavity overlay as an example,the direct calculation results of the non-rigid plate element method and the finite element simulation are in good agreement,which verifies the effectiveness of the method.Based on this method,the variation of target intensity before and after the cavity covering layer is installed in single-shell submarine and double-shell submarine is calculated and analyzed.The target intensity of submarine after the cavity covering layer is installed at different grazing angles is analyzed and summarized,as well as the influence of different cavity covering layer on the submarine target intensity.Based on the asymptotic scattering algorithm and the reflection coefficient of the cavity overlay,the acoustic scattering characteristics of the cavity overlay are calculated.The proposed method and the non-rigid plate element method were used to calculate the target intensity of the submarine with the covering layer in the case of receiving and receiving combined setting.The results show that the calculation results of the two methods are in good agreement,which verifies the effectiveness of the method.Based on the proposed method,the scattered sound pressure level distribution nephogram,radiation direction diagram and positive transverse frequency response curve of the standard submarine with the cavity covering layer in the case of receiving and receiving combined setting are calculated and analyzed.