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斜浪长峰不规则波中船舶复原力变化计算 总被引:3,自引:0,他引:3
基于切片理论,先求解出船舶无横倾时在斜浪长峰不规则波中的垂荡和纵摇运动,确定出波面与船体的相对位置,再利用三个坐标系之间的转换关系,提出了任意斜浪长峰不规则波中船体各横剖面左右舷与波面一组或多组交点的求法及各浸水剖面面积的通用计算法;同时基于规则波复原力计算公式,提出了Froude-Krylov假说下的斜浪长峰不规则波中复原力计算公式。最后以一艘集装箱船为例,研究了其在斜浪不规则波中复原力变化,计算结果表明船-波相对位置是影响斜浪长峰不规则波中复原力变化的一个至关重要因素。 相似文献
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《水道港口》2017,(4):330-336
针对港域波浪在绕射、反射联合作用下波况复杂的特点,基于港口波浪整体物理模型试验,对不规则波作用下港域内波高扰动系数的分布规律进行研究。研究表明:在波浪绕射作用或波浪反射作用占主导地位的掩护区域,多向不规则波的扰动系数与谱峰周期正相关,且周期相差越大,扰动系数相差越大。在波浪反射占主导地位的波浪绕射联合作用下,单向不规则波的扰动系数随谱峰周期的变化无明显规律性关系,且波浪反射对波向十分敏感。在存在原有建筑物反射的物理模型试验中,需要将模型边界反射模拟准确,否则可能造成试验失败;数学模型亦然,对相关建筑物需选取合适的反射系数。研究结果对后续的港口工程建设有重要的借鉴意义。 相似文献
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系泊船舶的水平慢漂运动的自然频率远低于一阶运动的自然频率。本文对具有这一特性的模型试验中不规则波浪模拟所必需包含的成分波个数与系统的自然频率关系作了研究,并提出了在不规则波模拟中波频的分割间隔与系统的自然频率关系的准则。通过模拟计算并用三种不同方法产生的不规则波所得到的模型试验结果证实,凡符合这一准则,得到的模型试验结果是可靠的、否则将产生严重失真。 相似文献
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文章基于高阶近似抛物缓坡方程,利用线性叠加原理建立了自然地形条件下综合考虑水波折射、绕射的随机波模型。通过对Vincent和Briggs的不规则波实验资料的数值模拟,对本模型进行了验证,计算结果和实验结果符合得比较好。并且通过数值计算得出了一些重要结论,对工程计算有重要意义。 相似文献
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[Objective]To investigate ship motion and load responses in realistic 3D waves and overcome the limitations of the traditional 2D wave assumption, this paper develops a method for predicting ship motion and load responses in short-crested waves. [Method]The long- and short-term responses of ship motion and load in long- and short-crested waves are numerically predicted using the spectral analysis and statistical probability methods, respectively. The influence of directional function on ship response is also numerically analyzed. Moreover, tank model tests and a large-scale model sea trial are comparatively conducted to validate the difference between ship response and statistics in long- and short-crested irregular waves. [Results]The results show that when navigating against the waves in the same sea condition, the long-crested wave assumption overestimates the statistical mean value of ship load response, but underestimates extreme load in real seas. For long-crested waves, the ship motion and acceleration power spectrum is concentrated around a certain frequency band. [Conclusion]Ship motion and load responses in realistic 3D waves are significantly different from those in 2D long-crested waves. The directional function of short-crested waves also has a significant effect on ship motion and load responses. © 2023 The Author(s). 相似文献
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Two-dimensional and three-dimensional Green-Naghdi (GN) models equipped with a numerical wave-absorbing beach have been developed to simulate nonlinear, regular, and irregular wave propagation. The numerical beach is introduced near the downstream boundary to absorb outgoing waves. An appropriate amount of numerical damping and an appropriate length of numerical beach are investigated using numerical experiments. The results show that the GN models with a numerical beach work very well in simulating wave propagation in water in a small computational domain. 相似文献
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数值波浪水池及顶浪中船舶水动力计算 总被引:9,自引:3,他引:6
基于粘流理论建立了三维数值波浪水池,模拟了非线性波浪,并对规则波顶浪中前进的拘束船模的水动力进行了计算.数值模拟中,控制方程-RANS方程和连续性方程使用有限体积法离散,非线性自由面采用VOF方法处理;在入口边界模拟柔性造波板运动产生入射波,使用位于波浪水池尾部的人工阻尼区消波.给出了非线性规则波的模拟结果以及规则波顶浪中前进的拘束船模的水动力计算结果,并与理论解及DUT(Delfi University of Technology)的试验数据进行了比较,二者吻合良好. 相似文献
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基于VOF方法的不规则波数值波浪水槽的阻尼消波研究 总被引:3,自引:0,他引:3
对基于VOF方法的不规则波数值波浪水槽进行了阻尼消波研究。在水槽右端的出流边界处,设置了一定长度的海绵层来吸收波浪,海绵层的衰减系数采用线性分布的形式。通过不同入射波参数的数值计算结果,比较了不同形式的衰减系数和参数的海绵层消波效果,给出了对应不同波要素范围的海绵层参数取值范围。对浪高仪位置处波面历时采用两点法进行了分离,波浪的反射率满足计算要求,给出了数值水槽中不同时刻波面高度空间分布情况,应用快速傅里叶变换得到计算波谱,计算波谱与靶谱吻合较好,计算结果表明所采用的海绵层阻尼消波是一种很好的边界处理方式。 相似文献
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实际海洋环境中舰艇受到多种因素的作用,对舰艇的操纵控制、船舶运动等方面产生了影响.本文基于非规则长峰波的数值仿真,提出舰艇在波浪影响下干扰力的计算方法.从频谱分析角度出发分析舰艇干扰力的主要影响因素,为仿真舰艇在海洋环境下运动提供思路. 相似文献
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In this work, the C11 container ship is taken as an example to analyze its rolling performances in random longitudinal or oblique waves. Firstly, a dynamic model of C11 roll in random waves is improved, and it is verified by the model test and numerical simulation. Mathematically, this dynamic model is a one-dimensional stochastic differential equation with random parametric (and external) excitation. Secondly, an enhanced stochastic averaging method is proposed to solve this stochastic differential equation. The validity of the solutions was verified by Monte Carlo simulation. At last, the probabilistic characteristics of the extreme rolling response were investigated based on the calculated results using enhanced stochastic averaging method. According to the analysis, some advices for ship's manoeuvring can be put forward when ships are navigating in random waves. 相似文献