共查询到20条相似文献,搜索用时 31 毫秒
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为了进一步掌握平面被动式减摇水舱中水位变化对减摇效率的影响规律,为减摇水舱总体设计提供参考。根据目标船和减摇水舱结构特点,选择5档水舱水位和无水状态分别进行静水横摇衰减模型试验、规则波模型试验和4级海况不规则波模型试验,针对减摇水舱水位变化对目标船固有周期、阻尼特性、减摇效率的影响规律进行分析,确定最佳水位区间。研究结果表明,水舱水位增加对目标船横摇固有周期和阻尼系数都有影响,水舱水位在水舱总高50%以内,减摇效率随水位增加而提高,在50%~60%之间减摇效率最高,超过60%时,减摇效率有降低趋势。 相似文献
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为进一步掌握平面被动式减摇水舱内水位的变化对减摇效率的影响规律,以某万吨级溢油回收船为研究对象,选择5档水舱水位和无水状态分别进行静水横摇衰减模型试验、规则波模型试验和4级海况下的不规则波模型试验,对减摇水舱内水位的变化对目标船固有周期、阻尼特性和减摇效率的影响规律进行对比分析。研究结果表明:水舱内的水位增加对目标船的横摇固有周期和阻尼系数都有影响;当水舱内的水位在水舱总高的50%以内时,减摇效率随水位的增加而提高;当水舱内的水位在水舱总高的50%~60%范围内时,减摇效率最高;当水舱内的水位在水舱总高的60%以上时,减摇效率有下降的趋势。 相似文献
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减摇水舱是一种减小船舶横摇,抵抗横倾的常用装置.设计减摇水舱最重要的两个参数是固有频率和阻尼.目前常用的确定减摇水舱固有频率和阻尼的方法大致分两种:一是利用流体力学理论分析或者经验公式进行计算;二是通过试验的方式来测得.由于减摇水舱内水的流动特性比较复杂,所以理论计算十分复杂,而且得到的结果误差也比较大.经验公式只可作为粗略估计.试验的方式对实验台和船模的硬件要求比较高,而且周期比较长.文章提出了一种利用CFD软件进行仿真计算确定水舱固有频率和阻尼的新方法,并且和水舱摇摆台试验结果进行了对照,证明了其可行性和准确性. 相似文献
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非线性条件下被动式减摇水舱仿真研究 总被引:1,自引:1,他引:0
减摇水舱作为一种常见的减摇装置,人们对它进行了很多研究.分析减摇水舱常用的是线性数学模型,但是线性模型仅适合小幅横摇的情况,而且忽略非线性因素的影响对减摇水舱的减摇效果分析也有影响.文章研究了考虑非线性因素的情况下,减摇水舱的特性.使用Matlab/Simulink对被动式减摇水舱进行建模,解决了非线性模型难以解算的问题. 相似文献
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减摇水舱的设计首先要考虑与船体的适配,同时在设计中要重点考虑水舱的阻尼与周期特性,其中周期特性是水舱最基本的特性参数,适用周期范围越宽,减摇效果越理想。针对变周期减摇水舱的相当长度与一般U型水舱相当长度计算的不同之处——其连通道宽度可调且边舱面积随边舱外壁角变化而变化,通过积分方法推导出了可变周期减摇水舱相当长度的计算公式,提出了一种适用于变周期减摇水舱的估算方法。所设计的变周期减摇水舱采用连通道挡板控制改变周期,避免了气阀控制的时间延迟问题,还可根据船体运动规律调整连通道阻尼挡板以提高减摇效果。以某型船为例,建立了船舶减摇水舱仿真模型。经减摇水舱自由衰减振荡数值仿真方法验证,所提出的周期估算公式可靠。采用该模型研究了变周期减摇水舱的控制方法,结果表明,在其工作范围内,可使横摇角始终保持在8°以内,可以在5.5~18 s的周期范围内有效减摇,大大超过了被动式减摇水舱的工作频带。 相似文献
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基于RANS和非线性动力学方法的海洋平台供应船水舱减摇预报 总被引:1,自引:0,他引:1
在探讨带平面被动式减摇水舱的海洋平台工作船在横浪中的减摇问题上,采用RANS方法进行船舶和水舱的强迫运动模拟,通过数值处理得到船舶和水舱的水动力系数。假设在共振频率下船舶和水舱的横摇运动在达到稳态后可以解耦,由非线性动力学的方法求解船舶横摇运动,并在波浪中进行系列模型试验以研究减摇特性。海洋平台工作船具有多工况的特点,不同载况对应不同船舶固有周期,实际航行中对减摇水舱的使用就是通过改变水舱水深使水舱的周期等于船舶固有周期,而通过上述方法的快速计算,选择合适的水深和阻尼隔板可以达到理想的减摇效果。结论表明该方法可以预报不同方案下的船舶横摇运动,该思路在船舶的减摇水舱设计阶段可以提供参考价值,并且在实船航行中可以提供水深加载指导以适应复杂的多工况航行。文中研究结果被运用于一艘实船航行时水舱加水策略中。 相似文献
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Yoshiaki Hirakawa Tsugukiyo Hirayama Kouji Kakizoe Takehiko Takayama Shigeru Funamizu Naoki Okada Akiko Yamane 《Journal of Marine Science and Technology》2014,19(3):292-301
Anti-rolling is an important technique for safety and efficient ship operation. In the era of sailing ships, rolling motions were not so severe compared to those of modern ships running by prime mover without sails, because the sail itself had a damping effect on rolling motion. After propeller driven ships exceeded sailing ships in number and performance, namely, from the end of the nineteenth century, many types of anti-rolling–related techniques were invented and developed, of both passive and active types. Recently (2009, 2010), as sea trials, we carried out proto-type experiments on an anti-rolling system and confirmed its effectiveness. The new concept utilizes the so-called Corioli’s effect, which appears in the rotational coordinate system. Usually, this effect is considered as virtual, but the real effect appears when a mass moves in the radial direction in a rotating coordinate system. In the case of ship rolling, the vertical motion of a mass generates Corioli’s force to finally generate anti-rolling moment. This is the reason the system was named Vertical Weight Stabilizer (VWS). This new system was invented in 1998 by Hirayama, and confirmed by the model experiments in a towing tank. Numerical simulations were carried out by the Sea and Air Control System laboratory of Yokohama National University, but the actual system could not be realized, because we could not find an appropriate actuator. The key technology for the success of the current sea experiment is the powerful, high-speed, compact actuator for the vertical movement of the weight. In this paper, we introduce this new concept by adopting a simple experiment, the control system with new actuator used in an actual sea experiment, and report on the successful results. 相似文献
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Research on the influence of action between fin and anti-rolling tank on the integrated stabilization effect 总被引:1,自引:1,他引:0
YU Li-jun JIN Hong-zhang WANG Hui YANG Sheng 《船舶与海洋工程学报》2007,6(1):9-14
Through analyzing the roll model of the integrated system of fin and anti-rolling tank, this paper uses binomial equation to simplify the module and check how the approximate parameters simulate the original function. Based on the simplified module, the influence of fin and anti-rolling tank on the coefficient items of the roll module is discussed, and the influencing factors between fin and anti-rolling tank are analysed. And through simulation, the influence of action between fin and anti-rolling tank on the static characteristics, and the integrated stabilization effect, are analyzed. 相似文献
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Research on roll stabilization for ships at anchor 总被引:2,自引:0,他引:2
With the increasing importance of ocean exploitation, providing anti-rolling stability for ships at anchor has become more and more important. The lift-generation theory of traditional fin stabilizers is based on incoming flow velocity, which is not suitable for explaining lift generated at anchor. We analyzed non-steady flows, with forces on fin stabilizers generated by non-incoming flow velocity conditions, and gave a new lift-generation model. The correctness of the model was proven by comparing experimental results of fin stabilizer motion under non-incoming velocity conditions from the fluid computation software with that from the emulator of the lift-generation model. Finally, the model was used in an anti-rolling system on a ship and the reduction of roll was much better than what could be achieved by passive anti-rolling tanks. 相似文献
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可控式被动减摇水舱最佳相位PD控制策略研究 总被引:1,自引:1,他引:0
在"船舶-可控式被动减摇水舱"系统数学模型的基础上,综合船舶横摇运动信息设计最佳相位PD控制器,并对可控式被动减摇水舱气阀的开启和关闭进行控制。在不规则波下的仿真结果表明,与常规控制相比,采用最佳相位PD控制策略能够取得更好的减摇效果,最大程度上发挥可控式被动减摇水舱的减摇能力。 相似文献
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水舱阻尼是影响减摇水舱减摇性能的重要因素,在减摇水舱的工程应用中,如何获得最佳的水舱阻尼成为水舱设计最关键的环节之一。一般情况下,可以通过调节水舱挡板来改变水舱底部通道截面积的大小,以达到改善水舱阻尼的目的。本文利用FLUENT软件,计算了二维水舱模型中不同挡板开度条件下水舱稳定矩的变化,得到该仿真模型最佳阻尼所对应的挡板开度的参考数值,并与减摇水舱台架试验的结果进行比较,表明了利用数值仿真的方法来研究水舱阻尼是可行的,该数值仿真的结果是合理的。 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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基于SPH方法对液体在三维矩形容器中的非线性晃荡问题进行了数值模拟研究。采用镜像粒子边界建立三维模型,成功解决传统SPH方法在容器壁产生缝隙的问题。对横荡和横摇两种容器运动形式进行数值模拟,在液面时间历程、不同时刻液体形态、点压强以及液体晃荡作用力等方面与其他学者的实验研究结果和数值计算结果进行对比验证,表明此三维模型的正确性。 相似文献