拖曳线列阵声呐缆线振动特性及减振措施研究

Equipping the surface ships with towed linear array sonars has become an important underwater detecting approach for international anti-submarine warfare nowadays. Reducing the towed cable vibration to mitigate the flow-induced noise interference of sonar is a significant technical problem to be solved urgently. The existing researches concerning about the underwater slender structures’ vibration mainly focus on risers, whereas few attention is paid to the towed cable structures. The towed cable is the research object of this project, and its vibration characteristics in consideration of the surface ship’s wave-induced motions, structure design for passive vibration reduction and active vibration reduction control are investigated respectively, combined with numerical simulations and model experiments. The nonlinear dynamic numerical model of the towed cable under complicated towing cases is established, and the structural local and overall vibration characteristics are revealed with model experiments. The passive vibration reduction methods for towed cable are proposed, and the cable’s vibration amplitude under extreme cases is reduced at least 50% with structure optimal design. The optimal solution tool for the towed cable’s active vibration reduction is developed. Associated with the anti-submarine warfare requirements and the hydrological conditions of the working area, the optimal cable length and towing velocity that minimize the cable’s vibration can be obtained rapidly, making the cable’s vibration able to be suppressed actively according to the optimal solution. The research achievements of this project could effectively improve the detecting behaviors of towed linear array sonar, and the proposed idea of active vibration reduction control is compliant to the intelligent development trend for our army equipment.

由水面舰船搭载拖曳线列阵声呐执行探测任务已成为当今国内外反潜作战的重要手段。抑制拖缆振动以减弱声呐的流噪声干扰是目前亟待解决的关键技术问题。现有水下细长结构物振动问题研究大多聚焦于立管等结构，而对拖缆振动的关注度有限。本项目拟采用数值仿真与模型试验相结合的手段对舰船摇荡和非匀速拖航下拖缆振动特性、拖缆被动减振结构优化方案及拖缆主动减振控制方案三方面内容开展研究。建立复杂拖航工况下拖缆非线性动力学数值模型，并结合模型试验揭示拖缆局部和整体振动特性；掌握拖缆振动被动抑制方法，对拖缆结构进行优化设计，将极端工况下拖缆振动幅值减小至少50%；开发拖缆振动主动抑制优化求解工具，根据工作水域水文条件及反潜作战需要快速演算出使缆线振动较弱的最优缆长和拖航速度，实现拖缆主动减振控制。本项目研究成果可有效提升拖曳线列阵声呐探测性能，提出的主动减振控制概念顺应我军装备向智能化转型升级的发展趋势。

拖曳线列阵声呐常配备于驱逐舰和护卫舰上，主要应用于监测水下潜艇辐射噪声，进行远程监视、测向、测距和识别。拖曳线列阵声纳由水听器和缆线组成，在工作过程中，舰艇通过缆线以一定速度拖着水听器航行，可以对水下潜器进行实时监控。拖曳线列阵声呐在探测远距离信号或弱信号时，流噪声会影响探测效果，拖缆在工作过程中的流致振动是产生流噪声的主要来源之一，且在振动过程中拖缆在交变应力的反复作用下强度下降，会出现疲劳损伤并加速结构破坏。本项目对海洋拖缆结构振动及减振措施进行了较为系统的研究，旨在降低拖缆工作过程中的振动问题。.拖缆的涡激振动问题研究主要分为两个阶段，一是拖缆准静态特性研究，二是拖缆涡激振动研究。本项目首先采用数值模拟对拖缆的准静态平衡位形和固有频率进行了分析，拖缆平衡位形分为“上凸”形、“下凹”形和“直线”形，不同平衡位形会遭遇不同的流场，针对“直线形”拖缆，开展了在摇荡拖航和计及抑制装置工况下的拖缆涡激振动试验研究，得出了复杂拖航下拖缆涡激振动响应特性和抑制装置对拖缆涡激振动的影响机理，根据试验结果和流体力分解模型，提出了拖缆涡激振动数值预报模型，研究了不同拖曳参数和不同抑制装置布置下拖缆涡激振动特性，最后通过遗传算法，对拖缆长度、拖曳速度和抑制装置布置进行优化，以达到减小拖缆涡激振动的目的，实现了对拖缆涡激振动的被动和主动抑制。.本项目对复杂拖航工况下的海洋拖缆涡激振动特性和被动抑制、主动抑制手段进行了较为系统的理论、试验和数值研究，着眼于时变流场、动态边界及轴向参激等联合作用下大柔性海洋细长结构物多场耦合非线性动力学这一科学问题，研究内容涉及当下发展拖曳线列阵声呐亟待解决的关键技术难题，现实意义重大，对于掌握水下拖曳缆线振动机理及特性、被动抑制机制、主动抑制措施以及提升声呐探测精度及效率具有一定的指导意义。