冰-水-船耦合运动学特性研究

With global warming, polar shipping and resource exploration are becoming more and more realizable. Markets and countries are both raising urgent demand on polar ships. Polar ships usually navigate in the mixed fluid flow of ice and water. Thus the core mechanical problem is the fully multi-media and multi-scale interaction among ice, water and ship. Previous study paid more attention on the collision between ship and ice, rather than the mixed flow of ice and water and the fully interaction model among ice, water and ship. In order to study dynamic characteristics of interaction between polar ships and mixed flow of ice and water, the theoretical derivation, numerical simulation and model tests have been combined and adopted in this project. Mechanical characteristics of ice, interaction between ice and ship as well as mixed flow of ice and water have been studied firstly. Considering different characteristics of ice, water and ship, DEM, SPH and FEM are adopted to simulate them, respectively. At the same time, the interfaces between these media are specially treated to exchange messages and keep continuity. On this basis, numerical model and method for the interaction among ice, water and ship have been explored by using the DEM-SPH-FEM. Model tests and field measurements have been also conducted. The model is then used in the kinematic analysis of polar ships. It is aimed to reveal fully multi-media interaction mechanism of ice, water and ship in different regions such as ice-covered water and mixed ice-water flow, in order to make a significant progress on the research of kinematic and dynamic analysis of polar ships in China.

随着全球变暖，极地航行和资源开发变得日益重要，市场和国家均对极地航行船舶提出了迫切需求。极地航行船舶通常航行于冰水混合域内，冰-水-船形成多介质多尺度的耦合运动学问题，是极地航行船舶的核心力学问题。以往研究多关注冰-船碰撞的强相互作用，对于冰-水耦合尤其是冰-水-船耦合模型考虑不足。本项目拟结合理论推导、数值模拟和物理实验等多种手段，研究海冰力学特性、冰-船相互作用和冰-水耦合模型等。针对冰、水、船不同介质的属性特性，分别采用DEM、SPH和FEM方法建立模型，同时合理地处理介质间交界面的数据交换和连续条件。在此基础上综合采用DEM-SPH-FEM方法开发一套冰-水-船耦合运动学分析模型和数值计算方法，并开展相关的模型实验和现场测量。将此模型应用于极地航行船舶的运动性能分析中，以揭示冰盖区域和碎冰区域内冰-水-船多介质多尺度的耦合机理，进而推动我国极地航行船舶冰水动力学研究取得突破性进步。

随着全球变暖，极地航行和资源开发变得日益重要，市场和国家均对极地航行船舶提出了迫切需求。极地航行船舶通常航行于冰水混合域内，冰、水、船形成多介质多尺度的耦合运动学问题，是极地航行船舶的核心力学问题。以往研究多关注冰-船碰撞的强相互作用，对于冰-水耦合尤其是冰-水-船耦合作用考虑不足。.本研究结合理论推导、数值模拟和物理试验等多种研究手段，研究了冰船作用力学特性、冰水耦合动力特性。针对冰船作用力学特性的研究，通过渤海湾现场测试获得了海冰变形和破坏的关键力学量，为后续数值模型的建立提供校准依据；借助“雪龙”极地运输船研究了冰排与船舶作用时的两种典型破坏方式：艏部的弯曲破坏和舯部的挤压破坏；作为冰区船舶推进作用中的关键科学问题，研究了冰与桨叶的作用机理。针对冰水耦合动力特性研究，分别研究了冰盖区层冰与水的耦合动力特性和碎冰区碎冰与水的耦合动力特性，以及近远场区域的冰水耦合匹配特性，同时借助模型试验验证了数值模型的合理性。本研究重点建立了冰-水-船耦合运动学数值模型，开发了基于DEM-SPH-FEM耦合算法的冰-水-船耦合作用数值计算程序，其中，采用精细离散元模型实现了海冰变形与破坏特征的模拟，采用同属拉格朗日粒子法的DEM和SPH方法实现了冰水之间耦合作用。最后，基于建立的冰-水-船耦合作用模型和算法分析了船舶直航时的冰阻力和冰水混合域内的回转特性，揭示了冰盖区域和碎冰区域内冰-水-船多介质多尺度的耦合机理。.本研究突破了海冰离散元精细模型建立及模型参数选取问题、近远场不同尺度冰水耦合匹配特性、冰-水-船耦合作用的多尺度、多介质数值方法等关键科学问题，研究成果可为后续冰区船舶冰载荷预报提供理论基础，可有效支撑我国冰区船舶的生产设计和安全运营。