沿倾斜河床航行船舶水动力数值计算

发布时间：2018-01-15 14:23

本文关键词：沿倾斜河床航行船舶水动力数值计算　出处：《上海交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：船舶水动力性能可以分为快速性、耐波性和操纵性，其中船舶操纵性对船舶航行安全性尤为重要。长期以来，由于船舶操纵问题而导致的船舶碰撞、触底等海事事故时有发生；特别是近十年来，随着现代航运业的发展，一方面使得船舶不断向大型化发展，另一方面使得船舶在更多类型的限制水域中航行，从而使得船舶操纵变得更加困难，发生海事事故的危险性也越来越大。近十年来，随着国际海事组织（IMO）“船舶操纵性标准”的颁布实施和人们安全意识的提高，船舶操纵性逐渐引起了人们的关注并越来越受到重视。船舶在限制水域中航行时的水动力性能与其在无限水域中航行时有很大区别，尤其是在浅窄航道中，由于有限水深以及岸壁的存在，船舶会受到浅水效应以及岸壁效应的影响，从而引发更严重的操纵性问题。IMO颁布的“船舶操纵性标准”明文规定，在船舶设计初期，必须对其操纵性能进行预报和评估，但其针对的只是在无限水域中的情况。所以，为了保证船舶在限制水域中航行的安全性，有必要对船舶在限制水域中的操纵性能进行研究。上世纪末以来，计算机技术和计算方法有了很大发展，从而为计算流体动力学（CFD）方法在船舶水动力学问题中的应用打下了基础。经过这些年的发展，在船舶设计阶段采用CFD方法对船体粘性绕流场进行数值模拟并计算相关水动力已能够取得比较好的结果，CFD方法逐渐成为一种研究船舶操纵性的可靠而有效的手段。以往，船舶操纵性研究基本都采用约束船模试验法，该方法耗时长，费用高，且适应性差。而CFD方法不仅克服了模型试验法的缺点，还能够对船体粘性绕流场进行更深入的分析并对船型优化提供指导。CFD方法可以与模型试验法相结合，进行数值预报验证，从而取得更准确的预报结果。本文针对船舶在限制水域中航行的情况，以大型集装箱船KCS船模为研究对象，，采用基于有限体积法进行离散化的CFD通用软件FLUENT，通过求解雷诺平均N-S方程(RANS方程)，对船舶粘性流场进行数值模拟，并对船舶所受水动力进行计算，以获得船舶水动力的数值预报结果。本文主要研究了船舶在限制水域中航行的三种情况：（1）船舶在具有倾斜水底以及存在单侧垂直岸壁的限制水域中作直航运动；（2）船舶在倾斜岸壁限制水域中作直航运动；（3）船舶在倾斜岸壁限制水域中作斜航运动。将以上三种情况下船体水动力的计算结果与相关经验公式或理论计算结果进行了对比，以研究CFD方法的有效性；同时，对船-岸距离、斜底或岸壁倾角、水深、航速、漂角对船舶水动力的影响进行了分析。本文所采用的CFD方法可以在一定程度上对船舶在限制水域中航行的水动力性能进行预报和评估，所得到的结果可以为船舶在限制水域中航行时的操纵与控制提供参考，从而确保船舶安全航行。
[Abstract]:Ship hydrodynamic performance can be divided into rapidity, wave resistance and maneuverability, in which ship maneuverability is particularly important to the safety of ship navigation. For a long time, ship collision caused by ship maneuvering problem. Marine accidents such as hitting the bottom occur from time to time; Especially in the past ten years, with the development of modern shipping industry, on the one hand, it makes ships develop to a large scale, on the other hand, it makes ships sail in more types of restricted waters. As a result, ship handling becomes more difficult, and the risk of maritime accidents becomes more and more serious. With the promulgation and implementation of International Maritime Organization (IMO) ship maneuverability Standard and the improvement of people's safety consciousness, ship maneuverability has attracted more and more attention. The hydrodynamic performance of ships in restricted waters is very different from that in infinite waters, especially in shallow and narrow channels, because of the limited water depth and the existence of shoreline. Ship will be affected by shallow water effect and shoreline effect, which will lead to more serious maneuverability problem. IMO promulgated "ship maneuverability Standard" explicitly, in the early stage of ship design. Its maneuverability must be forecasted and evaluated, but only in the case of infinite waters. Therefore, in order to ensure the safety of ships navigating in restricted waters. It is necessary to study the maneuverability of ships in restricted waters. Since the end of 0th century, great progress has been made in computer technology and calculation method, which has laid a foundation for the application of computational fluid dynamics (CFD) method in ship hydrodynamics. In the phase of ship design, the CFD method is used to simulate the viscous flow field around the ship and to calculate the relative hydrodynamics. CFD method has gradually become a reliable and effective means to study ship maneuverability. In the past, constrained ship model test method was used in ship maneuverability research, which takes long time and high cost. The CFD method not only overcomes the shortcomings of the model test method. It is also possible to further analyze the viscous flow field and provide guidance for ship type optimization. The CFD method can be combined with the model test method to verify the numerical prediction and obtain more accurate prediction results. Aiming at the situation of ships navigating in restricted waters, this paper takes the KCS model of large container ship as the research object, and adopts the CFD general software FLUENT which is based on finite volume method to discretize. By solving the Reynolds average N-S equation and rans equation, the viscous flow field of a ship is numerically simulated, and the hydrodynamic force of the ship is calculated to obtain the numerical prediction results of the ship's hydrodynamic force. In this paper, we mainly study three cases of ship navigation in restricted waters: 1) the direct motion of ships in restricted waters with inclined bottom and with unilateral vertical shore walls; (2) the direct navigation motion of the ship in the restricted waters with inclined bank wall; (3) the ship moves diagonally in the restricted waters with inclined bank wall. The calculated results of the hull hydrodynamics under the above three conditions are compared with the relevant empirical formulas or theoretical results. To study the effectiveness of CFD method; At the same time, the influences of ship-shore distance, slope angle, depth, speed and drift angle on ship hydrodynamic force are analyzed. The CFD method used in this paper can predict and evaluate the hydrodynamic performance of ships sailing in restricted waters to a certain extent. The results obtained can provide a reference for the manipulation and control of ships navigating in restricted waters, so as to ensure the safe navigation of ships.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U661.3

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