Ship Slamming in Waves

该研究计划的目的是改进预测船舶在波浪中砰击的数值工具。将进行新的实验，以深入了解波浪中水的冲击物理学，并为验证研究提供实验数据。 ** 在极端海域航行的船舶可能会经历大幅度的运动，由于其重量，船头经常离开水并重新进入水。这种现象被称为砰击，它可以导致船舶结构上的高冲击载荷。砰击是船舶在大浪中结构完整性的一个问题。船舶在波浪中砰击载荷的预测是船舶设计中的重要问题。虽然砰击问题的研究已经取得了很大的进展，但大多数研究都集中在二维断面进入静水的数值和实验方法。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自由度运动的船舶在波浪中的3-D砰击的理解是有限的。该研究计划将通过改进数值方法和进行模型试验来预测船舶在波浪中的砰击。主要研究内容如下：（1）进一步发展基于约束插值剖面（CIP）的有限差分方法，计算船舶入浪问题;（2）在Memorial深水水池和拖曳水池中进行滑行船体和集装箱船船体两种三维船模的静水入浪模型试验。本文将研究具有恒定垂向速度和自由落体运动的船模沿着不同初始姿态下的入水情况。还将研究规模效应。模型试验结果，包括流场，压力和船舶模型上的负载，将用于验证数值方法。由于三维船舶撞击波浪的实验数据非常稀少，因此将努力为基准和验证研究提供高质量的模型试验数据。（3）基于改进的CIP工具和大量的二维和三维试验数据，考虑三维效应、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时域船舶运动程序MAPS中，以模拟船舶在包括砰击的大浪中的大幅运动。**通过拟议的研究，将培养海洋流体动力学领域具有强大计算和实验技能的高素质人员。本文的研究，特别是船舶砰击的数值计算方法和基准试验数据，将为国内外船舶水动力学研究做出贡献。*** **

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. *** **