非均匀层结流体中内孤立波与潜航器任意角度作用的力学特性研究

The internal solitary wave (ISW) is a kind of marine inner fluctuation with large amplitude and strong induced-flow velocity, and also is one of catastrophic marine environmental factors that affects the submersible-vehicle safety. The inhomogeneous stratification is one of basic characteristics in the ocean as well as the prerequisite which results in the ocean density cliffs. The angle between ISW propagation direction and submersible vehicle movement direction is usually varied, thus it is arbitrary. The variety of the interaction angle may lead to the load magnitude sudden change so that it can seriously threaten the safety of .submersible vehicles. In this project both the experimental method of physical model and theoretical modeling method will be used to study the interaction between internal solitary wave and the submersible vehicle at the arbitrary angle in the inhomogeneous stratification fluid. The experimental platform for the ISW generation，propagation and its load on submersible vehicles will be constructed. The mechanical characteristics for different cases such as fluid stratifications, ISW elements, depth and angle of submersible vehicles will be obtained. The quantitative applicable boundary of typical internal solitary wave nonlinear model will be obtained from the ISW experiments, and the theoretical calculation model of the load on the ISW to the submersible is established under the arbitrary angle in an inhomogeneous stratification fluid that effectively solving the problem of the ISW force. This project will profoundly reveal the hydrodynamic performance of the ISW with the submersible in the actual marine environment and clarify the mechanical mechanism that may cause the submersible vehicle to be unstable or even wreck.

内孤立波是一种振幅大、诱导流速强的海洋内部波动，也是影响潜航器安全的灾害性海洋环境因素。非均匀层结是实际海洋分层的基本特性，亦是产生“海底断崖”的前提条件。内孤立波传播与潜航器运动方向是变化的，故内孤立波与潜航器作用角度具有任意性，作用角度变化可改变作用力特性甚至威胁潜航器安全。本项目拟采用物模实验和理论建模方法，研究非均匀层结流体中内孤立波与潜航器任意角度作用下的力学问题。构建内孤立波生成演化及其对潜航器作用的实验平台，对内孤立波特征及潜航器作用力进行测量与分析，探讨流体层结、内孤立波要素、潜航器潜深及不同作用角度下的力学特性；实验确定典型内孤立波非线性模型成立参数定量适用边界，建立非均匀层结流体中内孤立波与潜航器任意角度的高精度作用力计算模型，有效解决内孤立波对潜航器作用力问题。本项目将揭示实际海洋中内孤立波对潜航器任意角度下水动力学特性，阐明可能导致潜航器失稳甚至损毁的力学机理。

内孤立波是一种振幅大、诱导流速强的海洋内部波动，也是影响潜航器安全的灾害性海洋环境因素。针对海洋内孤立波与潜航器作用的实际场景，开展非均匀层结流体中内孤立波与潜航器任意角度作用的力学特性研究，阐明内孤立波对潜航器安全危害性动力学机理。研究内容主要包括：非均匀层结流体中内孤立波生成演化与潜航器任意角度作用力特性的模型实验研究；非均匀层结流体中内孤立波传播及其与潜航器任意角度的作用力计算模型理论研究；非均匀层结流体中内孤立波与潜航器任意角度相互作用机理研究。研究重要结果：1）模型实验方面，构建了内孤立波生成演化及其对潜航器作用的实验平台，对内孤立波特征及潜航器作用力进行测量与分析；系统地获得了下凹型和上凸型内孤立波生成演化特性，确定了典型内孤立波非线性模型成立参数定量适用边界；实验分析了分层环境、作用角度、潜深等要素对作用力的影响，另外，完成了考虑潜航器涡旋脱落所致升力条件下作用力特性研究； 2)模型理论方面，采用典型内孤立波非线性理论结合流体动力学方程，建立了非均匀层结流体中内孤立波与潜航器任意角度的高精度快速化作用力计算模型，该模型可在任意作用角度、振幅及潜深条件下给出潜航器所受到的水平力、垂向力及扭矩情况； 3）机理分析方面：基于模型实验和理论结果，重点探讨了分层流体层结、内孤立波振幅、潜航器潜深及作用角度等关键要素对内孤立波对潜航器力学特性的影响，阐明了内孤立波对潜航器危害性机理。相关成果发表于高水平期刊Ocean Engineering（2020、2023、2023，3篇）、Physics of Fluids （2021）、Journal of Fluids and Structures（2022）、Journal of Marine Science and Engineering（2022）；申请授权相关专利10项。本项目的研究不仅对海洋内波生成演化特性、水下潜航器水动力学特性及潜航器在复杂海洋环境中的适应性等方面具有重要学术意义，而且对实际海洋中内孤立波监测预警、潜航器在复杂海洋环境操纵性和航行安全的评估决策等方面有重要实际应用价值。