Ship Slamming in Waves

提出的研究计划的目的是改进数值工具来预测船舶在波浪中撞击。将进行新的实验，以深入了解波浪中水的物理影响，并为验证研究提供实验数据。******在极端海域航行的船舶，由于自身的重量，船首会频繁地出水并重新入水，从而经历剧烈的运动。这种现象被称为撞击，它会对船舶结构产生高脉冲载荷。碰撞是船舶在大浪中的结构完整性问题。在船舶设计中，波浪冲击载荷的预测是非常重要的。******虽然在解决撞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使用数值和实验方法进入平静水域的二维截面上。最近的研究已经扩展到平静水中的三维尸体，其中一些正在进行实验测试。然而，对具有六自由度运动的船舶在波浪中进行三维撞击的理解是有限的。提出的研究计划将通过改进数值方法和进行模型试验，重点研究船舶在波浪中撞击的预测。研究总结如下：(1)将进一步发展基于约束插值剖面（CIP）的有限差分方法来计算船舶入水；(2)将在Memorial的深槽和拖曳槽中对两个船舶模型（3d），一个平面船体和一个集装箱船船体进行模型试验，进入静水和波浪。我们将研究具有恒定垂直速度和自由落体运动的船舶模型在不同初始姿态下的入水情况。规模效应也将被研究。模型试验结果，包括流场，船舶模型上的压力和载荷，将用于验证数值方法。由于三维船舶撞波实验数据很少，我们将努力为基准研究和验证研究提供高质量的模型试验数据。进行不确定度分析，量化模型试验中的不确定度；(3)利用改进的CIP工具和实验数据，在广泛的二维和三维研究的基础上，考虑三维效应、波浪效应和船舶初始姿态等因素，建立新的半解析模型。半解析模型将集成到基于无面板方法的时域船舶运动程序MAPS中，以模拟涉及撞击的大浪中的大振幅船舶运动。******通过本计划的研究，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。所提出的研究，特别是船舶在波浪中撞击的数值方法和基准实验数据，将对国内外船舶水动力学领域做出贡献。* * * * *

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. *** **