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为研究深水养殖平台的水动力特性及其锚泊系统的安全性,以“振渔二号”深水养殖平台为例,开展物模试验和数值仿真计算。测试该平台在极限风速和流速下的外载荷作用力,并对其进行规则波频率运动响应试验和数值模拟,同时对其锚泊系统进行风、浪、流联合作用下的运动和系泊受力试验,获得该平台的水动力及其锚泊系统的受力特征值。物模试验和数值计算结果表明:忽略网衣的影响,纯波浪作用对平台运动的影响较小;在横风、横浪、横流作用下,锚泊系统最大受力对应的安全系数满足船级社相关指南的要求,有一定的安全裕度。研究成果可供深水养殖平台及其锚泊系统的优化设计和作业安全评估参考。 相似文献
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考虑浮体弹性变形的锚泊系统分析方法 总被引:1,自引:0,他引:1
传统的锚泊系统分析方法一般是假设结构物为刚性不可变形的,这种假设对于常规海洋结构物的锚泊系统分析,其精度是可以接受的,然而对于弹性体(比如超大型浮体)来说,这种浮体刚性的假设显然是不合理的.本文基于摄动理论,分别给出了锚泊浮体(同时包括弹性体和刚性体)和锚泊系统的一阶运动方程.分别用三维水弹性理论和Goodman-Iance法求解浮体的动力响应和锚泊线的运动,并给出了两者之间的协调关系.通过数值算例分析表明,对于超大型浮体,其弹性特性对锚泊系统特性的影响是不可忽略的. 相似文献
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针对锚泊线的非线性特性,采用三维弹性杆理论推导锚泊线的控制方程,并应用迦辽金法将方程离散成适用于锚泊线动力分析的微分方程形式。针对锚泊线上端受高频一阶波浪力的扰动作用显著的特点,提出采用具有可控数值阻尼,能够有效地滤除高频响应的广义α算法对锚泊线进行动力分析,并在原有广义α算法的基础上,提出适用于变质量系统的改进型广义α算法。同时分别从理论研究和实例分析角度将广义α算法与传统的Newmark算法进行对比,结果表明广义α算法在稳定性,准确性及数值阻尼特性等方面均具有优势。 相似文献
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为研究不同锚泊方式悬浮隧道在随机波作用下的动力响应,设计对应的节段模型试验,分析考虑随机波作用的3种锚泊方式悬浮隧道的动力特性。根据相似准则,考虑波流水槽的尺寸,设计几何比尺为1∶150的物理模型试验。将数值模拟结果与试验结果相对比,验证试验结果的准确性和可靠性。开展不同工况下的模型试验,分析随机波作用下3种典型锚泊方式悬浮隧道管体结构的横荡、垂荡和横摇运动响应,以及锚索的受力情况。研究结果表明:锚泊方式1的抑振能力最差,锚索缆力最大,安全性最差;锚泊方式2在垂荡方向上具有较好的抑振能力,锚索缆力比锚泊方式1小;锚泊方式3在横荡、纵荡、横摇运动响应和锚索缆力方面的表现均较佳,安全性更好。该研究可供悬浮隧道工程及其他类似工程的锚泊设计提供参考。 相似文献
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本文采用数值计算方法对浅水中海洋平台支持船(OSV)的锚泊定位性能开展研究.首先,基于三维频域势流理论,对一艘OSV不同水深的水动力性能开展分析,计算了水动力系数、运动幅值响应算子、一阶波浪力和二阶波浪力.由于浅水中非线性效应显著,本文采用中场公式计算了该OSV全二阶波浪力传递函数(Full Quadratic Transfer Function,简称全QTF).然后,本文对不同水深下锚泊系统的水平刚度开展了分析,计算了不同水深下锚泊系统的水平刚度,研究了水深对锚泊系统水平刚度的影响.最后,采用准动态方法对不同水深下的OSV和锚泊系统开展时域分析,研究了水深对船体运动性能和锚索张力的影响. 相似文献
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Chong Ma Kazuhiro Iijima Yasunori Nihei Masahiko Fujikubo 《Journal of Marine Science and Technology》2016,21(3):396-415
In this paper, we discuss nonlinear motion of a buoy connected vertically to the seabed via a tensioned tether (tethered-buoy). A series of scaled model tests has been conducted and a significant nonlinear behavior of the buoy motion, sub-harmonic motion in particular, is observed. Taking account of the influence of time-varying tether tension on the buoy motion, theoretical explanation is made for the sub-harmonic response. The stability of the tethered-buoy system is focused based on Mathieu instability theory. A strongly coupled numerical model between the buoy motion and the tether behavior is established to clarify the mechanism of the nonlinear motion of the tethered-buoy system. A comparison between the experiment data and simulation results is presented not only for the linear but also for the sub-harmonic components. Influential factors for the sub-harmonic motion are discussed in detail. It turned out that the sub-harmonic motion is dominated by the nonlinear coupling effect of time-varying tension in the tether with the buoy motion. Finally, the influential factors to the sub-harmonic motion are indicated throughout the comparison between two different buoy models. 相似文献
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采用悬链线理论精确地计算浮标漂移量与锚链力的关系曲线;通过B样条拟合求得锚链张力;从而达到锚泊系统的时域快速精准模拟。本文对于锚泊-浮体系统的研究有一定的指导意义。 相似文献
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This article is about the use of measured wave-induced vessel motions for estimation of ocean wave spectra by application of the wave buoy analogy. In the study, data from a larger, in-service container ship is considered. The estimation of wave spectra, equivalently sea state parameters, is based on measurements from, respectively, a gyro and two accelerometers leading to the simultaneous use of the pitching motion together with the horizontal and vertical accelerations in a position close to the forward perpendicular. The study of in-service data leads to contemplations about the vessel's advance speed, as the possible existence of sea current means that speed-over-ground (SOG) and speed-through-water (STW) will be different. The article discusses aspects related to advance speed in the context of the wave buoy analogy, and a smaller sensitivity study is conducted. Preceding to the sensitivity study, a comparison is made between sea state estimates by the wave buoy analogy and estimates obtained from a hindcast study. The article shows an acceptable agreement between the two sets of estimates. Following, the main conclusion from the sensitivity study on advance speed is that errors and uncertainties in the speed log have an effect on the estimates of the wave buoy analogy. In fact, the effect can be severe if reliable STW measurements are not available. In the final part, the article includes a few discussions about (non)stationary conditions in the context of the wave buoy analogy, and, although the effect on results is not necessarily detrimental, care must be shown when the wave buoy analogy is applied during in-service conditions. 相似文献
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Floating structures oscillate in waves, where these wave-induced motions may be critical for various marine operations. An important consideration is thereby given to the sea states at the planning and operating stages for an offshore project. The most important information extracted from a sea state is the directional wave spectrum, indicating wave direction, significant wave height, and wave spectrum peak period. Among several available methods of measuring and estimating the directional wave spectrum, the wave buoy analogy technique based on vessel motion responses is an in situ and almost real-time solution without extra costs of devices. If the forms of the wave spectra are not predefined in the estimation, the method is called a nonparametric approach. Its most remarkable advantage is the flexible form, but the smoothness should be regulated. After the discrete Fourier transform has been applied to the measured vessel motions, smoothing is necessary. However, this process results in disturbed vessel cross-spectra and a lowpass characteristic of the windowing function. This paper presents a nonparametric approach for directional wave spectrum estimation based on vessel motion responses. It introduces novel smoothness constraints using Bézier surface and includes a more robust estimate using L1 optimization. Both techniques are applied to the wave buoy analogy for the first time. Numerical simulations are conducted to verify the proposed algorithm. 相似文献