水下多层结构目标体的高频回声特性研究

The Study of High-frequency Echo Characteristics of Underwater Multiple-layer Targets

水下装置很多都是多层结构。为准确预报其高频回声特性,提出平面元方法结合基于传递矩阵的多层结构反射特性计算方法的混合方法研究水下三维多层结构目标体的高频回声特性,并研究多层圆板、圆球和有限长圆柱等水下多层结构三维目标体的回声特性。计算结果表明,水下目标体的第一Fresnel波带表面的曲率变化平缓时,采用的方法和局部反应表面处理方法的结果是基本一致的。而第一Fresnel波带表面的曲率变化不平缓时,方法的计算结果更符合实际声学特性。

Multiple-layer structures have been used for many underwater equipments. In present paper a hybrid technique that planar elements method combined with the method calculating the reflection characteristics of multiple-layer structures based on transfer matrix method is developed for more exactly studying high-frequency echo characteristics of underwater targets with multiple-layer structures. The echo characteristics of multiple-layer disk, sphere and finite cylinder have been studied with the hybrid technique. The results indicate that if the curvature change of first Fresnel wave zone is not gently, the hybrid technique results more match the actual acoustic characteristics. Otherwise it is equivalent to the local plane wave approximation.