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CFD simulation of 3-dimensional motion of a ship in waves: application to an advancing ship in regular heading waves 总被引:1,自引:0,他引:1
A new computational fluid dynamics simulation method has been developed for the unsteady motion of a ship advancing in waves.
The objective is to evaluate the added resistance and predict the performance of a ship in waves. In this study, a finite
volume method, in the framework of a boundary-fitted grid system, is employed. The motion of the ship is solved with six degrees
of freedom by using the hydrodynamic forces and moments obtained from the solution of the simulation method. The marker–density–function
method is employed to calculate the nonlinear free surface. This method is applied to the coupled motion problem of heaving
and pitching.
Received for publication on Nov. 15, 1999; accepted on Nov. 18, 1999 相似文献
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规则波浪中舰船操纵与横摇耦合运动模拟及特性分析 总被引:2,自引:0,他引:2
采用六自由度舰船操纵性方程与横摇波浪力矩耦合构成动力学模型,对舰船在规则波浪中的操纵与横摇耦合运动特性进行了模拟研究.其中操纵性方程采用MMG模型,波浪力矩由切片法计算,舰船航向按PD控制.模拟计算了某船正横规则波浪下保持航向的横摇运动,计算结果与单自由度理论结果进行了比较,其幅频曲线与相频曲线两者符合较好,间接证明了耦合构成动力学模型的有效性.在此基础上计算了不同浪向角和航速下的横摇运动,以横摇等值极坐标曲线表征舰船规则波浪中的横摇特性,从而给出了规则波浪下舰船耦合动力学所描述的运动特征. 相似文献
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This paper presents the results of an experimental investigation dealing with the effect of bow overhang extensions on the quantity of shipping water over the foredeck in case of ships advancing in regular head waves. To perform this investigation, a series of free-running tests was conducted in regular waves using an experimental model of a multipurpose cargo ship to quantify the amount of shipping water. The tests were performed on five bow overhang variants with several combinations of wavelength and ship speed conditions. It was observed that the quantity of shipping water was affected by some parameters such as wavelength, ship speed, and bow shape in terms of an overhang extension. The results show the significant influence of an overhang extension, which is associated with the bow flare shape, on the occurrence of water shipping. These results involve the combined incoming regular waves and model speed. 相似文献
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船舶拖航系统六自由度操纵运动仿真 总被引:2,自引:1,他引:1
研究拖航作业操纵运动对于提高拖航作业的安全性有重要意义,采用MMG分离式船舶运动数学模型,结合拖缆的悬链线张力计算模型,建立由拖轮、拖缆、被拖轮组成的拖航系统六自由度操纵运动模型,编制仿真程序,通过数值计算,对该系统操纵运动进行仿真模拟。以拖轮和导管架驳船的拖航运动为例,分析拖缆长度、拖航速度对拖航系统操纵运动及拖航航向稳定性的影响,模拟该系统在风、浪、流影响下的操纵运动,运动数据实时解算,为在视景模拟平台上进行作业预演,规避拖航作业风险提供理论指导。 相似文献
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This article presents a nonlinear time-domain simulation method for the prediction of large-amplitude motions of a Ro–Ro
ship in regular oblique waves in an intact and a damaged condition. Numerical computations and model tests have been carried
out to investigate the dynamic motion responses of Ro–Ro ship Dextra to various wave amplitudes at three different wave headings. The results of numerical and experimental investigations for
stern quartering waves are reviewed. Comparisons between predictions and measurements show good agreement except in the roll-resonant
region. Nonlinear effects are significant in horizontal modes of motion, and resonant roll motion, and there is strong coupling
between all modes of motion in the roll-resonant region for large-amplitude responses. On the other hand, the time-domain
simulation technique suffers from numerical drift in horizontal modes of motion as wave amplitude increases. This is due to
nonlinear equations of motion and the lack of a restoring force and moment in horizontal motion.
Received: April 30, 2002 / Accepted: August 9, 2002
Acknowledgments. II Programme of the European Community Commission under contract No. BRPR-CT97-0513.
Address correspondence to: H.S. Chan (hoi-sang.chan@ncl.ac.uk) 相似文献
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Kristjan Tabri Petri Varsta Jerzy Matusiak 《Journal of Marine Science and Technology》2010,15(1):87-101
A calculation model to simulate nonsymmetric ship collisions, implying an arbitrary impact location and collision angle, is
described in the paper. The model that is introduced is based on the time integration of twelve equations of motion, six for
each ship. The motions of the ships are linked together by a mutual contact force. The contact force is evaluated as an integral
over the surface tractions at the contact interface. The calculation model provides full time histories of the ship motions
and the acting forces. Physical understanding of the underlying phenomena was obtained by a series of model-scale experiments
in which a striking ship collided with an initially motionless struck ship. In this paper, numerical simulations of four nonsymmetric
collisions are presented and the calculations are validated with the results of the experiments. 相似文献
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选取浙江舟山近岸淤泥质泥沙为研究对象,采用规则波对淤泥质泥沙的起动进行水槽试验研究。结果表明,淤泥质泥沙具有薄层轻微悬扬、表层个体剥离、泥团卷起悬扬3种典型的起动状态,同一水深下的泥沙起动波高随波周期的增大而递减。以泥团卷起悬扬状态作为判断淤泥质泥沙起动的标准,佐藤公式、窦国仁公式计算的起动波高均与本文试验值总体上接近,可将两家公式计算结果的平均值用于淤泥质泥沙起动波高的估算。泥团卷起悬扬状态下过程最大含沙量往往在0.8~2.0 kg/m~3,过程最大含沙量随临界切应力增大而呈现明显的指数递增关系。研究成果便于深入了解淤泥质海岸地区泥沙在波浪环境下的水力特性,同时可为海岸泥沙数模计算及工程分析的参数选取提供参考。 相似文献
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波浪中破损船舶的运动会同时受到波浪激励和进出水的影响,而船体运动也会影响进出水过程,二者的相互影响机理十分复杂.本文重点研究波浪中破舱进出水对船舶运动响应的影响,文中首先基于势流理论建立了考虑破舱进出水的4DOF(横荡-垂荡-横摇-纵摇)相互耦合时域预报方法,在计算中假设舱内的液面水平,利用修正的伯努利方程模拟破舱进/出水,利用Ikeda's经验公式修正阻尼系数.然后以一艘ITTC破损稳性标模为例,研究了波浪中考虑破舱进出水的数学模型以及破舱进出水对运动响应的影响,并研究了不同自由度、破舱口位置对运动响应的影响.研究表明,本文基于势流理论建立的时域预报方法可以定量的预报破损船舶的运动响应. 相似文献
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迎浪规则波中波浪增阻和船体垂向运动的数值预报(英文) 总被引:1,自引:0,他引:1
The numerical prediction of added resistance and vertical ship motions of one ITTC (International Towing Tank Conference) S-175 containership in regular head waves by our own in-house unsteady RANS solver naoe-FOAM-SL JTU is presented in this paper. The development of the solver naoe-FOAM-SJTU is based on the open source CFD tool, OpenFOAM. Numerical analysis is focused on the added resistance and vertical ship motions (heave and pitch motions) with four very different wavelengths (0.8Lpp≤λ≤1.5Lpp) in regular head waves. Once the wavelength is near the length of the ship model, the responses of the resistance and ship motions become strongly influenced by nonlinear factors, as a result difficulties within simulations occur. In the paper, a comparison of the experimental results and the nonlinear strip theory was reviewed and based on the findings, the RANS simulations by the solver naoe-FOAM-SJTU were considered competent with the prediction of added resistance and vertical ship motions in a wide range of wave lengths. 相似文献
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顶浪规则波中小水线面双体船纵向运动特性数值分析 总被引:1,自引:0,他引:1
基于RANS方程和VOF模型求解船体粘性兴波流场,采用Overset技术处理船体运动,开展了小水线面双体船(Small Waterplane Area Twin Hulls,SWATH)迎浪规则波中运动响应特性及其产生机理的研究.通过数值计算结果与模型试验结果的对比分析,验证了本文方法的有效性;在此基础上,分析了船体运动响应曲线中各峰值产生的原因及片体间相互干扰对SWATH船在波浪中运动响应的影响,发现其中一个峰值出现的原因为遭遇频率接近船体运动固有频率,由此发生共振;另一个峰值的出现则可能与SWATH特殊的船型及附体配置有关.由于SWATH船片体间的水动力干扰效应,SWATH船在波浪中运动响应峰值较单个片体响应峰值明显减小,且出现的位置向低频方向移动. 相似文献
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《舰船科学技术》2016,(15)
基于RANS方程和VOF模型求解船体粘性兴波流场,采用Overset技术处理船体运动,开展了小水线面双体船(Small Waterplane Area Twin Hulls,SWATH)迎浪规则波中运动响应特性及其产生机理的研究。通过数值计算结果与模型试验结果的对比分析,验证了本文方法的有效性;在此基础上,分析了船体运动响应曲线中各峰值产生的原因及片体间相互干扰对SWATH船在波浪中运动响应的影响,发现其中一个峰值出现的原因为遭遇频率接近船体运动固有频率,由此发生共振;另一个峰值的出现则可能与SWATH特殊的船型及附体配置有关。由于SWATH船片体间的水动力干扰效应,SWATH船在波浪中运动响应峰值较单个片体响应峰值明显减小,且出现的位置向低频方向移动。 相似文献