水下角反射组合体声散射特性

Acoustic scattering properties of underwater corner reflector complexes

[目的]为进一步提高水下凹面目标散射声场的计算速度和精度,开展水下角反射组合体声散射特性的研究。[方法]基于Kirchhoff近似和射线追踪基本理论,考虑角反射体的多次散射和遮挡影响,建立水下角反射组合体声散射预报的简化模型,提出水下角反射组合体目标散射声场的快速预报方法,即改进板块元法(PEM)。通过此方法,计算三角形三面角反射体散射声场,并通过有限元仿真予以验证;在此基础上,以八面角反射体为基元,研究八面角以及组合多面角反射体结构的特性、集群强散射目标回声特性和基于空间的强散射目标特性。[结果]研究表明:改进的PEM法可以准确和快速地计算角反射体的散射声场;八面角及组合多面角反射体的散射声场随入射波频率、角度和组合体间距等的变化而改变。[结论]研究结果可为水下无源干扰体模型设计提供重要的技术支撑。

[Objective]In order to further improve the speed and accuracy of calculating the acoustic scattering fields of underwater concave targets,the acoustic scattering characteristics of underwater corner reflector complexes are studied.[Method]By applying the Kirchhoff approximation and ray tracing methods,and considering the multiple effects of scattering and occlusion by corner reflectors,a simplified acoustic scattering prediction model of an underwater corner reflector complex is established and a rapid prediction method(i.e.modified planar element method,PEM)of acoustic scattering fields is proposed.The acoustic scattering field of a corner reflector complex is calculated by this method and verified via finite element simulation;on this basis,an analysis is made of the characteristics of octahedral corner reflectors,combined polyhedral corner reflectors and cluster-based and space-based strong scattering targets.[Results]The results show that the modified PEM allows the rapid and accurate calculation of the acoustic fields scattered by diagonal reflectors.The acoustic scattering fields of octahedral corner reflectors and combined polyhedral corner reflectors varies with the incident wave frequency,angle and reflector complex distance.[Conclusion]The results of this study can provide important technical support for the design of underwater passive interferer models.