水下等离子体声源聚束声场非线性建模和定向辐射机理研究

Bunching sound field modeling and numerical studies of underwater plasma sound source based on nonlinear effects can provide important theoretical references for directional radiation mechanism research. In the existing methods, the sound field modeling methods based on curve reflector bunching can neither describe the exact bunching sound field distribution characteristics, nor obtain the real evolution information of sound field; the bunching sound field nonlinear modeling methods based on array bunching is just at the beginning stage. In this project, the research is focused on nonlinear modeling and mechanism. Based on the nonlinear effect and directional radiation theory, through researching on the complex sound field description of the curve reflector bunching and the array bunching, the multi factor entity model of the nonlinear bunching sound field and the new model of the equivalent pulse sound source modeling can be established. A relatively systematic new method of numerical simulation and experimental study can also be proposed. Based on the test results and simulation results, the bunching sound field performance can be analyzed. The research can not only enrich and improve the directional radiation theory, but also provide novel theoretical references for optimization of sound source and effective control of bunching performance parameter. This project could be considered as the deepening and expansion of the previous research projects. The prospective achievements of the project can be expected to have wide applications in underwater acoustic countermeasure，ultra remote secure communication and target fast and accurate detection ability as well as other fields.

基于非线性效应的水下等离子体声源聚束声场建模与数值模拟研究可为定向辐射机理研究提供准确理论依据。现有的基于曲面反射聚束的声场建模方法即无法准确描述聚束声场的分布特性，也难以获得声场真实的演化信息；而基于阵列聚束的非线性聚束声场建模尚处于起步阶段。本项目针对聚束声场非线性建模和定向辐射机理展开研究，将非线性效应与水下等离子体声源定向辐射理论相结合，分别针对曲面反射聚束和阵列聚束条件下的复杂声场描述问题，建立多要素非线性聚束声场实体模型以及等效脉冲声源新模型，提出较为系统的数值模拟和试验研究新方法，联合数值模拟结果和试验结果，系统的分析聚束声场性能，进一步丰富水下等离子体声源定向辐射理论体系，为优化声源和有效控制聚束性能参数提供新的理论依据。本项目是前期相关科研项目研究的深化和拓展，预期研究成果对于提升我国水声对抗、超远程保密通信和水下目标快速精准探测能力具有重要的理论意义和实用价值。

本项目瞄准大功率水下等离子体声源（UPSS）的重大应用需求，通过研究UPSS电弧放电的微观过程和冲击波波形参数的关系，提出了UPSS阵列聚束实现方法，建立了大功率、非线性条件下的UPSS曲面反射聚束声场模型和阵列聚束声场模型，通过理论研究和实验研究相结合的方法，实现了非线性聚束声场的准确描述，掌握了聚束声场分布规律。具体研究内容如下：（1）深入研究了UPSS电声转换模型、系统声效率模型、预击穿机理、单声源能量预测等理论，掌握了电弧放电微观过程及系统参数与冲击波波形参数的宏观关系，提出了盐水中进行UPSS阵列聚束的实现方法；（2）提出了一种优化的五阶对称WENO数值计算方法，反推了等效脉冲声源初始激励波形，建立了非线性曲面反射聚束声场模型，结合数值模拟研究和实验研究，分析了多种因素影响下的曲面反射聚束声场特性；（3）给出了UPSS阵列聚束设计方案和实现方法，建立了直达波阵列聚束声场模型，分析了不同聚束方式、阵列参数影响下的直达波阵列聚束声场分布特性，重点结合UPSS双声源聚束实验系统，建立了UPSS双声源聚束声场模型，分析了双声源聚束的聚束声场分布特性和演化过程。本项目的研究为解决大功率、非线性条件下的聚束声场描述问题提供了可靠的技术途径。研究成果对于提升我国水声对抗、超远程通信和水下目标精准探测具有重要的意义，在军事和民用领域均有十分广阔的应用前景。