Development of computer codes to predict the wave loads and the response of ships and offshore structures in waves

开发计算机代码来预测波浪载荷以及船舶和海上结构在波浪中的响应

• 批准号: 09555313
• 负责人: OHKUSU Makoto
• 金额: $ 6.91万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09555313/
• 关键词: Nonlinearity; Finite Amplitude Motion; High Waves; Numerical Computation; Ship Motion in Waves; Offshore Strcture; Simulation; 大振幅動揺

Objectives of our research are :1. Derivation of a theoretical method, which is based on correct modelling and reliable in accuracy, to predict waveﾟCload, wave impact pressure, the effect of sea water on deck on ships and offshore structures in rough seas.2. To develop a computer code to simulate various responses of ship and offshore structures at consistent accuracyﾟCbased on theoretical modellings developed in 1.Summary of the main results :1. We developed a computer code to compute finite amplitude motioms of high speed vessels in rough seas. TheﾟCmathematical model for this code is 2.5D theory combined with weak scatterer assunption. This modelling has aﾟCbenefit to let the computation more consistent and robust.2. A full nonlinear formulation of the 2D flow around a cylindrical body in high waves was provided. Mixed Eulerian-Lagrangia approch was utilized in the time domain. We completed a computer code based on this approch and are continuing the effort to incooporate this code in 2.5D code for the high speed vessels. It will complete our plan to obtain a computer code to simulate accurately ship motions in rough weather.3. We developed a mathematical theory and a computer code based to predict hydroelastic responses of large offshore structures in waves4. We confirmed accuracy of our mathematical model of wave impact pressure generated by the pitch motion of ships in high waves with experiment.5. We found that fully theoretical prediction of dynamic process of sea water entering on deck is not easy with the capability of available compiuters ; a semi-empirical approch to this problem is useful to develop a simulation code.

本研究的目的是：1.推导出一种基于正确建模和可靠精度的理论方法，用于预测波浪载荷、波浪冲击压力、甲板上海水对船舶和海洋结构物的影响.在1中建立的理论模型的基础上，开发了一个计算机程序，以一致的精度模拟船舶和海洋结构物的各种响应。本文编制了一套计算高速船在大风浪中有限幅运动的程序。本程序采用2.5维理论结合弱散射体假设的数学模型。这种建模有一个好处，让计算更一致和鲁棒.给出了高波中圆柱体二维绕流的完全非线性方程。时域采用欧拉-拉格朗日混合方法。我们完成了一个基于这种方法的计算机代码，并正在继续努力将此代码纳入2.5D代码的高速船舶。这将完成我们获得一个计算机代码来精确模拟船舶在恶劣天气中运动的计划。我们开发了一个数学理论和计算机代码，以预测大型海洋结构物在波浪中的水弹性响应4。通过实验验证了所建立的船舶在高浪中纵摇运动产生的波浪冲击压力数学模型的准确性.我们发现，在现有计算机的能力下，完全理论预测海水进入甲板的动态过程是不容易的，半经验的方法来解决这个问题是有用的，以开发一个模拟代码。

项目成果

H.Iwashita: "Influence of the Steady Flow in Seakeeping of a Blunt Ship through the Free Surface Condition" Proc.of 13th.Intl.Workshop on Water Waves and Floating Bodies, Alphen aan den Rijin. 89-92 (1998)

H.Iwashita：“通过自由表面条件稳定流对钝船耐波性的影响”第 13 届水波和浮体国际研讨会论文集，Alphen aan den Rijin。

M.Ohkusu and Y.Namba: "Hydroelastic Behavior of a Large Floating Platform of Elongated Form on Head Waves in Shallow Water" Proc.of 2nd Intl.Conf.on Hydroelasticity in Marine Technol-ogy, Fukuoka. 177-183 (1998)

M.Ohkusu 和 Y.Namba：“浅水中头波上细长形式大型浮动平台的水弹性行为”，第二届海洋技术水弹性国际会议论文集，福冈。

M.Ohkusu: "Validation of Theoretical Methods for Ship Motions by Means of Experiment" Proc.22nd Intl.Symp.of Naval Hydrodynamics, Washington, D.C.(1998)

M.Ohkusu：“通过实验验证船舶运动的理论方法”Proc.22nd Intl.Symp.of Naval Hydrodynamics，华盛顿特区（1998）