Ship Slamming in Waves

提出的研究计划的目标是改进预报船舶在波浪中撞击的数值工具。将进行新的实验，以深入了解波浪中水冲击的物理过程，并为验证研究提供实验数据。*在极端海面上航行的船只可能会经历大幅度的运动，其船头经常出水，并因其重量而重新入水。这种现象被称为砰击，这可能会导致船舶结构受到高冲击载荷。对于大浪中的船舶来说，砰击是一个结构完整性问题。在船舶设计中，预报波浪中的砰击载荷是非常重要的。尽管在解决砰击问题方面已经取得了很大的进展，但大多数研究都集中在进入平静水中的二维横断面上，采用数值方法和实验方法。最近的研究已经扩展到静水中的三维物体，其中一些正在进行实验测试。然而，对于具有6个自由度运动的船舶，对波浪中的三维砰击问题的理解是有限的。建议的研究计划将重点放在通过改进数值方法和进行模型试验来预报船舶在波浪中的撞击。(1)将进一步发展基于约束内插剖面(CIP)的有限差分方法来计算船舶入波；(2)在纪念馆的深水池和拖曳水池中进行两个船模(一个滑行体和一个集装箱船船体)进入平静水和波浪中的模型试验。将考察具有恒定垂直速度和自由落体运动以及不同初始姿态的船模的入水情况。还将调查规模效应。模型试验结果，包括船模上的流场、压力和载荷，将被用来验证数值方法。由于三维船舶撞击海浪的试验数据非常少见，将努力为基准和验证研究提供高质量的模型试验数据。对模型试验中的不确定度进行了不确定度分析；(3)在利用改进的CIP工具和试验数据进行了广泛的二维和三维研究的基础上，考虑了三维效应、波浪效应和船舶初始姿态等因素，建立了一个新的半解析模型。半解析模型将被集成到基于无面板方法的船舶运动时域程序MAPS中，以模拟船舶在包含砰击的大浪中的大振幅运动。通过拟议的研究，将培养具有较强计算和实验技能的海洋流体力学领域的高素质人才。本文的研究成果，特别是船舶在波浪中砰击的数值方法和基准试验数据，将为国内外船舶水动力领域的发展做出贡献。*

The objective of the proposed research program is to improve numerical tools to predict ship slamming in waves. New experiments will be carried out to gain insight into the physics of water impact in waves and to provide experimental data for validation studies. ******A ship travelling in extreme seas can experience large-amplitude motions with its bow frequently out of water and re-entering water due to its weight. This phenomenon is called slamming, which can result in high impulsive loads on ship structures. Slamming is a concern of structural integrity for ships in large waves. It is important to predict the loads due to slamming in waves in ship design.******Although great progress has been made in solving slamming problems, most studies have been focused on 2-D sections entering into calm water using numerical and experimental methods. Recent studies have been extended to 3-D bodies into calm water and some of them are on experimental tests. The understanding of 3-D slamming in waves for a ship with 6-DOF motions is however limited. The proposed research program will focus on the prediction of ship slamming in waves by improving the numerical methods and by carrying out model tests. The research is summarized as follows: (1) A constrained interpolation profile (CIP)-based finite difference method will be further developed to compute water entry of ships into waves; (2) Model tests will be carried out in Memorial's deep tank and towing tank for two ship models (3-D), one planing hull and one container ship hull, entering calm water and waves. Water entries of the ship models with constant vertical velocities and free-fall motions along with different initial attitudes will be examined. Scale effects will also be investigated. Model test results, including the flow fields, pressures and loads on ship models, will be used to validate the numerical methods. Since the experimental data for 3-D ship slamming into waves is very rare, efforts will be made to provide high-quality model test data for benchmark and validation studies. Uncertainty analysis will be carried out to quantify uncertainties in model tests; (3) Based on extensive 2-D and 3-D studies using the improved CIP tool and the experimental data, a new semi-analytical model will be developed by considering factors such as 3-D effect, wave effect and the initial attitude of ship. The semi-analytical model will be integrated into the panel-free method-based time-domain ship motion program, MAPS, to simulate large-amplitude ship motions in large waves involving slamming.******Through the proposed research, highly qualified personnel in the area of marine hydrodynamics with strong computational and experimental skills will be trained. The proposed research, especially the numerical methods and the benchmark experimental data for ship slamming in waves, will contribute nationally and internationally to the field of ship hydrodynamics. *** **