共查询到20条相似文献,搜索用时 15 毫秒
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Sloshing of liquid can increase the dynamic pressure on the storage sidewalls and bottom in tanker ships and LNG careers. Different geometric shapes were suggested for storage tank to minimize the sloshing pressure on tank perimeter. In this research, a numerical code was developed to model liquid sloshing in a rectangular partially filled tank. Assuming the fluid to be inviscid, Laplace equation and nonlinear free surface boundary conditions are solved using coupled FEM-BEM. The code performance for sloshing modeling is validated against available data. To minimize the sloshing pressure on tank perimeter, rectangular tanks with specific volumes and different aspect ratios were investigated and the best aspect ratios were suggested. The results showed that the rectangular tank with suggested aspect ratios, not only has a maximum surrounded tank volume to the constant available volume, but also reduces the sloshing pressure efficiently. 相似文献
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基于OpenFOAM的船舶与液舱流体晃荡在波浪中时域耦合运动的数值模拟 总被引:4,自引:0,他引:4
波浪中载液船舶运动激励舱内液体的晃荡,舱内液体晃荡产生的冲击力同时作用在舱壁上,进而影响船舶的运动姿态。波浪中船体水动力和时延函数是在势流理论范畴下采用切片法和脉冲响应函数方法计算获得的,液舱内液体非线性晃荡是基于粘性流理论实时计算模拟,两者耦合建立了波浪中载液船舶与液舱流体晃荡耦合的运动方程。论文基于开源CFD开发平台OpenFOAM,自主开发实现了船体运动与液舱晃荡的耦合计算程序,并进行了相应的数值模拟计算和验证工作。该方法完整地考虑了波浪、船体和液舱晃荡之间的耦合作用,并结合船体内外流场特点分别采用了势流和粘性流理论,具有较高的计算效率。通过数值模拟计算和模型实验研究表明,数值模拟计算能够清晰显现出液舱晃荡对船体全局运动影响,船体运动计算结果与模型实验结果吻合良好。 相似文献
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In this research,liquid sloshing behavior in a 2-D rectangular tank was simulated using ANSYS-FLUENT software subject to single or multiple-coupled external excitations(such as sway coupled with roll,and sway and roll coupled with heave).The volume of fluid(VOF) method was used to track the free surface of sloshing.External excitation was imposed through the motion of the tank by using the dynamic mesh technique.The study shows that if the tank is subjected to multiple coupled excitations and resonant excitation frequencies,liquid sloshing will become violent and sloshing loads,including impact on the top wall,will be intensified. 相似文献
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晃荡是一种非常复杂的非线性液体流动现象,载液船舶的晃荡问题颇受关注,因为在外界的激励下液舱内会产生剧烈的晃荡现象,巨大的晃荡冲击力会造成结构的破坏.文中建立了三维晃荡数学模型及数值计算模型,借助处理自由表面的VOF(volume of fluid)方法对液舱内液体晃荡的自由表面进行追踪,编制程序实现了液舱内三维液体非线性晃荡的数值模拟,并就三维刚性液舱内粘性液体的自由晃荡和强迫晃荡做了分析,讨论了液体不同粘性系数对晃荡的影响.模拟结果证明了三维晃荡理论的可行性. 相似文献
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基于Youngs法的液舱大幅晃荡数值模拟 总被引:1,自引:0,他引:1
液舱大幅晃荡一直是船舶水动力学研究的热点问题.文章采用Youngs法重构自由表面,给出了自由表面单元的速度边界条件,并且对液体晃荡中出现的流体翻卷、破碎后出现的流体波面的锋-锋相遇的情况进行了分析和讨论.数值模拟结果表明,Youngs法结合适当的自由表面条件,能够较好地模拟液舱内大幅晃荡中出现的翻卷和破碎的现象. 相似文献
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为分析LNG船B型独立液货舱的支撑结构在晃荡载荷作用下的受力情况,建立二维有限元模型,简化支撑结构,基于任意拉格朗日-欧拉方法和体积模量缩减技术,采用Abaqus对液舱晃荡进行数值仿真,得到不同工况下支撑结构作用力随时间的变化情况。有结论以下:1)周期性横摇使支撑结构作用力周期性变化;2)横摇幅值越大,作用力变化范围越大;3)与固体货物相比,装载等密度等体积液体货物时,作用力变化范围更大;4)在液货舱内设置挡板能够降低作用力变化范围。本文采用的计算方法和得到的结论能够为初步设计阶段支撑结构的强度及疲劳分析提供帮助。 相似文献
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以水下航行器水平液舱内的液体晃荡问题为研究对象,基于VOF方法建立二维水平液舱数值模型,研究不同外部激励对液舱晃荡造成的响应。通过仿真计算2种特殊工况下自由液面的晃荡状态,分析数值仿真模拟和文献结果的误差,证明了模型计算的精确性。在矩形液舱计算的基础上,进一步对和海洋工程实际形状类似的半圆-矩形液舱进行模拟分析。通过计算分析各个影响参数对液舱晃荡的影响,得到压载水舱内的波高历时曲线以及舱壁上某监测点处的压力时间曲线。数值模拟计算的结果误差较小,为减小晃荡对水下航行器的影响提供了理论依据。 相似文献
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Nonlinear interactions among incident wave, tank-sloshing and floating body coupling motion are investigated. The fully nonlinear sloshing and body-surface nonlinear free surface hydrodynamics is simulated using a Non-Uniform Rational B-Spline (NURBS) higher-order panel method in time domain based on the potential theory. A robust and stable improved iterative procedure (Yan and Ma, 2007) for floating bodies is used for calculating the time derivative of velocity potential and floating body motion. An energy dissipation condition based on linear theory adopted by Huang (2011) is developed to consider flow viscosity effects of sloshing flow in nonlinear model. A two-dimensional tank model test was performed to identify its validity. The present nonlinear coupling sway motion results are subsequently compared with the corresponding Rognebakke and Faltinsen (2003)’s experimental results, showing fair agreement. Thus, the numerical approach presented in this paper is expected to be very efficient and realistic in evaluating the coupling effects of nonlinear sloshing and body motion. 相似文献
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In order to explore the characteristics of the single-layer liquid sloshing in offshore dry oil storage tank and the two-layer liquid sloshing in offshore wet oil storage tank, two series of experiments were carried out: one was free surface sloshing in a closed rectangular tank partially filled with colored water, and the other was interfacial sloshing in the identical tank but completely filled with white oil and colored water. The tank was mounted on a shake table and was subjected to harmonic horizontal excitation with different excitation amplitudes and a wide range of excitation frequencies, including the first seven natural modes of single-layer or two-layer liquid system. The present study find that the frequency responses of interfacial sloshing wave are analogous to those of the free surface sloshing wave, but smaller in amplitudes. The experiments also produce results that are unique to the two-layer liquid sloshing. For example, when the external excitation frequency is equal to or close to the odd mode natural frequency of two-layer liquid system, a complicated three-dimensional (3D) gravity-capillary wave might be generated at the oil-water interface. Finally, the comparisons of free surface and interfacial sloshing in the viscous damping ratio, higher sloshing modes, impact pressure amplitude and mass center displacement were conducted, which revealed the superiority of wet storage technology in structural safety and dynamic stability. 相似文献
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In the present study a novel modeling approach is presented to solve the combined internal sloshing and sea-keeping problem. The model deals with interesting effects arising due to the coupled interaction between the sloshing in partially filled containers of several geometries and the ship motion. The study is very important for the liquid cargo carrier operating in rough sea or under different environmental conditions. The resulting slosh characteristics that include transient pressure variation, free surface profiles and hydrodynamic pressure over the container walls have been reported in this study. In addition, the effects of coupled ship response and sloshing on ship motion parameters have also been investigated. The equations of motion of fluid, considered inviscid, irrotational, and partially compressible, are expressed in terms of the pressure variable alone. A finite difference-based iterative time-stepping technique is employed to advance the coupled solution in the time domain. Several parameters of interest, including the container parameters, level of liquid, thrusters modeling and some important environmental factors are investigated. 相似文献