Inversion Methods Of Ocean Bubble Parameters Based On Acoustic Characteristics

There are a large number of bubbles in the ocean.Due to the great differences in the density,acoustic impedance and compressibility of air and water,the acoustic characteristics of the seawater medium containing bubbles often change significantly.As a strong scattering body,bubbles(especially a large number of bubbles in the resonance state under the action of sound waves)will have a great impact on the propagation of sound waves It has important research value in underwater sonar detection,ship wake recognition,acoustic parameter array and many other research fields.According to the different acoustic intensity,the seawater with bubbles presents obvious linear and non-linear acoustic scattering characteristics(specifically attenuation,scattering,dispersion,non-linear scattering and so on).According to these acoustic characteristics directly related to the physical characteristics of bubbles,the parameters of bubble group parameters can be obtained,such as bubble group size distribution,bubble concentration and porosity.In this paper,the inversion method of ocean bubble parameters based on the characteristics of acoustic scattering is studied systematically.On the basis of obtaining the correlation between the sound velocity,linear acoustic scattering/attenuation,nonlinear acoustic scattering / attenuation and nonlinear parameters of the medium with bubbles and the distribution of bubble groups,a variety of acoustic scattering models are established,supplemented by a variety of overcoming matrices The optimal numerical method of the over fitting problem in the inversion process is used to obtain the inversion results of the size distribution parameters of the bubble group stably.In the study of the linear acoustic inversion method of bubble group parameters,the influence of nonresonant bubble on sound velocity and sound scattering / attenuation is fully considered,and the rationality of transforming integral equation into matrix equation inversion is deeply studied;in the study of the nonlinear acoustic inversion method of bubble group parameters,the unique nonlinear acoustic scattering characteristics of bubbles are used to effectively separate a large number of sea surface and impurities In order to improve the accuracy of the inversion results,the influence of environmental factors is studied.Furthermore,a new inversion method based on the nonlinear parameters of the medium with bubbles is proposed.Through theoretical and simulation analysis,it is proved that this method has higher stability and enriches the inversion method of the size parameters of the bubble group.Based on the theoretical analysis and summary of the application scope,advantages and disadvantages of various inversion methods of ocean bubble parameters based on linear and non-linear acoustic scattering characteristics,the paper further designs the parameters inversion experiment of electrolytic bubble group in the water tank to obtain more reasonable experimental results,which provides support for verifying the correctness of the inversion method.