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3D Effects on Vortex-Shedding Flow and Hydrodynamic Coefficients of A Vertically Oscillating Cylinder with A Bottom-Attached Disk

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China Ocean Engineering 2017年第4期31卷 428-437页

作者： WANG Quan kou yu-feng ZHU Ren-qing CHEN Hong State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai 200240China School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhengjiang 212002China Shanghai Waigaoqiao Shipbuilding CO. LTD.Shanghai 200240China

Vortex-shedding flow induced by the vertical oscillation of a cylinder with bottom-attached disks of different diameter ratio Dd/Dc and thickness ratio td/Dc is studied by a 3D （three-dimensional） numerical model developed in this paper, and compared with the results obtained through 2D （two-dimensional） numerical model. The high-order upwind scheme is applied to stabilize the computation, and convergence is accelerated by the multi-grid method. Qualitative and quantitative analyses of the differences between the 2D and 3D simulation results reveal the 3D effect on the flow field characteristics and hydrodynamic coefficients of the vertically oscillating cylinder with a bottom-attached disk. The 3D effect on the fluid field is mainly reflected in the significance of three vortex-shedding patterns： ωx has a greater effect on the flow fields around the sharp edges relative to the vortices generated in the 2D simulation. In the slice along the axial orientation, the vortex effect of ωy along the radial axis is smaller than that of ωx along the circumferential direction, indicating the radial effect on the velocity more pronounced than the circumferential effect around the sharp edges of the disk. The rotational interaction ωz of the fluid in the horizontal plane during the heave motion is insignificant. Based on the 2D and 3D simulation results, the turning points that separate the increasing regimes of the added mass coefficient and damping ratio are identified. The dependence of the turning point on the diameter ratio Dd/Dc and thickness ratio td/Dc are discussed in detail.

关键词： 3D effect vortex-shedding pattern added mass coefficient damping ratio vertical oscillation

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Numerical and Experimental Study on Hydrodynamic Performance of A Novel Semi-Submersible Concept

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China Ocean Engineering 2018年第2期32卷 144-156页

作者： GAO Song TAO Long-bin kou yu-feng LU Chao SUN Jiang-long State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai Jiao Tong UniversityShanghai 200240China Department of Naval Architecture and Marine Engineering University of StrathclydeGlasgowG11XQUnited Kingdom China Ship Development and Design Center Wuhan 430064China School of Naval Architecture and Ocean Engineering Huazhong University of Science and TechnologyWuhan 430074China

The Multiple Column Platform(MCP) semi-submersible is a newly proposed concept, which differs from the conventional semi-submersibles, featuring centre column and middle pontoon. It is paramount to ensure its structural reliability and safe operation at sea, and a rigorous investigation is conducted to examine the hydrodynamic and structural performance for the novel structure concept. In this paper, the numerical and experimental studies on the hydrodynamic performance of MCP are performed. Numerical simulations are conducted in both the frequency and time domains based on 3D potential theory. The numerical models are validated by experimental measurements obtained from extensive sets of model tests under both regular wave and irregular wave conditions. Moreover, a comparative study on MCP and two conventional semi-submersibles are carried out using numerical ***, the hydrodynamic characteristics, including hydrodynamic coefficients, natural periods and motion response amplitude operators(RAOs), mooring line tension are fully examined. The present study proves the feasibility of the novel MCP and demonstrates the potential possibility of optimization in the future study.

关键词： multiple column platform(MCP) semi-submersible platform numerical simulation model test response amplitude operators(RAOs)

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Structural Stress Monitoring and FEM Analysis of the Cutting Operation of the Main Bracket of A Semi-Submersible Platform

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China Ocean Engineering 2019年第6期33卷 649-659页

作者： kou yu-feng YANG Jian-min XU Sheng-wen PENG Tao LIU Jun WU Zhuo-wei State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University

For a semi-submersible platform in repair, the eight old main brackets which connect columns with pontoons need to be replaced by new ones. In order to ensure the safety of the cutting operation of the old main bracket and calculate the initial stress condition of new main bracket, the structural stress monitoring of eight key spots is carried out, and then the calibrated finite element model is established according to the field monitoring results. Before cutting the main bracket and all associated structures, eight rectangular rosettes were installed, and a tailored cutting scheme was proposed to release the initial stress, in which the main bracket and associated column and pontoon plates were partly cut. During the cutting procedure, the strains of the monitoring spots were measured, and then the structural stress of the monitored spots were obtained. The stress variation characteristics at different spots during the initial cutting operation were shown and the initial stress condition of the monitored spots was figured out. The loading and support conditions of the semi-submersible platform were calibrated based on the measured initial stress condition, which made the finite element model more credible. The stress condition with the main bracket and associated structures being entirely cut out is analyzed by the Finite Element Method (FEM), which demonstrates the cutting operation to be safe and feasible. In addition, the calibrated finite element model can be used to calculate the initial stress condition of the new main bracket, which will be very helpful for the long-term stress monitoring on the main bracket.

关键词： semi-submersible platform main bracket cutting operation field stress monitoring FEM analysis

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Experimental Study on New Multi-Column Tension-Leg-Type Floating Wind Turbine

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China Ocean Engineering 2018年第2期32卷 123-131页

作者： ZHAO Yong-sheng SHE Xiao-he HE Yan-ping YANG Jian-min PENG Tao kou yu-feng State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200030China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration(CISSE) Shanghai Jiao Tong UniversityShanghai 200030China Shanghai University of Engineering Science School of ManagementShanghai 201620China

Deep-water regions often have winds favorable for offshore wind turbines, and floating turbines currently show the greatest potential to exploit such winds. This work established proper scaling laws for model tests, which were then implemented in the construction of a model wind turbine with optimally designed blades. The aerodynamic,hydrodynamic, and elastic characteristics of the proposed new multi-column tension-leg-type floating wind turbine(Wind Star TLP system) were explored in the wave tank testing of a 1:50 scale model at the State Key Laboratory of Ocean Engineering at Shanghai Jiao Tong University. Tests were conducted under conditions of still water, white noise waves, irregular waves, and combined wind, wave, and current loads. The results established the natural periods of the motion, damping, motion response amplitude operators, and tendon tensions of the Wind Star TLP system under different environmental conditions, and thus could serve as a reference for further research.

关键词： floating wind turbine model test WindS tar TLP dynamic response

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Study on Global Performances and Mooring-Induced Damping of A Semi-Submersible

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China Ocean Engineering 2016年第5期30卷 671-686页

作者： XIONG Ling-zhi YANG Jian-min LV Hai-ning ZHAO Wen-hua kou yu-feng State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai 200240 China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai Jiao Tong University Shanghai 200240 China Faculty of Engineering Computing and Mathematics The University of Western Australia Crawley WA 6009 Australia

The harsh environmental conditions bring strong nonlinearities to the hydrodynamic performances of the offshore floating platforms, which challenge the reliable prediction of the platform coupled with the mooring system. The present study investigates a typical semi-submersible under both the operational and the survival conditions through numerical and experimental methods. The motion responses, the mooring line tensions, and the wave loads on the longitudinal mid-section are investigated by both the fully non-linearly coupled numerical simulation and the physical experiment. Particularly, in the physical model test, the wave loads distributed on the semi-submersible＇s mid-section were measured by dividing the model into two parts, namely the port and the starboard parts, which were rigidly connected by three six-component force transducers. It is concluded that both the numerical and physical model can have good prediction of the semi-submersible＇s global responses. In addition, an improved numerical approach is proposed for the estimation of the mooting-induced damping, and is validated by both the experimental and the published results. The characteristics of the mooring-induced damping are further summarized in various sea states, including the operational and the survival ~nvironments. In order to obtain the better prediction of the system response in deep water, the mooring-induced damping of the truncated mooring lines applied in the physical experiment are compensated by comparing with those in full length. Furthermore, the upstream taut and the downstream slack mooring lines are classified and investigated to obtain the different mooring line damping performances in the comparative study.

关键词： semi-submersible physical model tests mooring-induced damping numerical simulation

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暗礁波浪演化及大型坐礁船波浪载荷研究

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船舶力学 2022年第9期26卷 1278-1289页

作者：黄铮寇雨丰肖龙飞陈世海李俊上海交通大学海洋工程国家重点实验室上海200240 上海交通大学三亚崖州湾深海科技研究院海南三亚572024 交通运输部上海打捞局上海200090

针对KeaTrader在杜兰德礁触底事故,本文提出简化物理模型,通过水池模型试验对波浪在礁盘上的演化、坐礁船总体波浪载荷进行研究,并基于合田波压修正公式计算得到坐礁船波浪载荷幅值。波浪从礁盘边缘斜坡往礁盘顶部传播过程中,波高增大,... 详细信息

针对KeaTrader在杜兰德礁触底事故,本文提出简化物理模型,通过水池模型试验对波浪在礁盘上的演化、坐礁船总体波浪载荷进行研究,并基于合田波压修正公式计算得到坐礁船波浪载荷幅值。波浪从礁盘边缘斜坡往礁盘顶部传播过程中,波高增大,波峰变陡,直至发生破碎,礁盘顶部两侧波浪破碎比中部更早,同时礁盘顶部逐渐形成圆弧形波浪。随着入射波陡增大,礁盘顶部波浪破碎更明显,礁盘中心区域波高降低更显著;同时,试验得到的横向和垂向波浪载荷均表现出先减小后增大的趋势,通过力平衡分析发现坐礁船可能发生滑动。最后以坐礁船波浪载荷试验结果为基准,通过与基于合田波压修正公式的计算结果比较,建立了一种快速估算坐礁船波浪载荷的方法。

关键词：暗礁坐礁船波浪演化波浪载荷模型试验

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深水半潜式平台运动响应及截面波浪载荷模型实验研究（英文）

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船舶力学 2018年第6期22卷 714-726页

作者：熊凌志杨建民寇雨丰魏汉迪张泽宇上海交通大学海洋工程国家重点实验室上海200240

半潜平台在恶劣的海洋环境中将承受极端的环境载荷,从而导致相应的大幅运动,截面载荷以及系泊力。文章对一艘系泊在南海的典型半潜平台进行了综合试验研究。为了测量中纵剖面上的波浪载荷,半潜平台模型从中纵剖面处被剖开,并用3个六分... 详细信息

半潜平台在恶劣的海洋环境中将承受极端的环境载荷,从而导致相应的大幅运动,截面载荷以及系泊力。文章对一艘系泊在南海的典型半潜平台进行了综合试验研究。为了测量中纵剖面上的波浪载荷,半潜平台模型从中纵剖面处被剖开,并用3个六分力传感器进行连接。结果表明,当波浪周期在10 s附近时,中纵剖面处的截面传递函数达到最大值。而低频长波以及差频波浪成分对剖面载荷影响很小。文中还分别针对仅有波浪作用的海况和风、浪、流联合作用的海况,对半潜平台的运动和载荷情况进行了研究,发现风和流对平台波频运动影响较小,而对于低频运动,其影响要大于波浪作用。随着风和流的出现,中纵剖面的剪切力,分离力以及垂向弯矩增幅分别可达127.07%,51.87%和45.77%。与此同时,在风、浪、流的联合作用下,最大锚链力与锚链的破断强度比值达到了62.3%,接近规范中66.6%的限制。

关键词：半潜平台试验研究截面载荷波浪载荷系泊系统

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半潜式平台波浪砰击测试方法与载荷特性研究

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船舶力学 2021年第4期25卷 426-434页

作者：郭英豪肖龙飞卢文月寇雨丰上海交通大学海洋工程国家重点实验室上海200240 高新船舶与深海开发装备协同创新中心上海200240

本文采用模型试验的方法对半潜式钻井平台受到的水平波浪砰击载荷进行了研究。为了克服模型结构动力响应的影响,试验时设计了专用的测量单元用于监测波浪砰击载荷,并采用小波分析的方法对砰击载荷试验数据进行降噪处理。试验结果表明:... 详细信息

本文采用模型试验的方法对半潜式钻井平台受到的水平波浪砰击载荷进行了研究。为了克服模型结构动力响应的影响,试验时设计了专用的测量单元用于监测波浪砰击载荷,并采用小波分析的方法对砰击载荷试验数据进行降噪处理。试验结果表明:半潜式平台水平波浪砰击载荷的发生频率和砰击冲量随有义波高的增加而增加,但砰击载荷幅值则体现了显著的非线性和随机性特征,砰击载荷冲量的随机性和发散性则相对较小;平台立柱与箱型甲板连接处的砰击载荷较大,大多数海况下后立柱砰击频率和砰击载荷幅值比前立柱更高。

关键词：砰击载荷半潜式平台模型试验小波降噪空间分布

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新型超大型浮式海上基地消浪室方案试验研究

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船舶力学 2016年第7期20卷 833-840页

作者：寇雨丰肖龙飞刘建辉杨立军上海交通大学海洋工程国家重点实验室上海200240 高新船舶与深海开发装备协同创新中心上海200240 海洋石油工程股份有限公司设计公司天津300451

新型超大型浮式海上基地(VLFOB)设计采用了由两层直立开孔式消浪墙组成的消浪室结构。根据内、外消浪墙开孔率的不同,提出6组消浪室方案。通过模型试验研究,对比分析不同消浪室方案下的消波效率和VLFOB水动力性能,结果表明:一般地,消浪... 详细信息

新型超大型浮式海上基地(VLFOB)设计采用了由两层直立开孔式消浪墙组成的消浪室结构。根据内、外消浪墙开孔率的不同,提出6组消浪室方案。通过模型试验研究,对比分析不同消浪室方案下的消波效率和VLFOB水动力性能,结果表明:一般地,消浪室开孔率越小,消波效率越高,VLFOB的纵荡幅值和系泊力越大,单体间连接载荷相对较大;相同消浪室方案下,入射波能级提高使得消波效率降低;采用内外开孔率分别为0.16和0.24的消浪室方案,不仅消波效率较高,而且单体间的连接载荷也较小。

关键词：超大型浮式结构物海上基地消浪室模型试验

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半潜式平台垂向运动对气隙影响的概率统计分析

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海洋工程 2014年第4期32卷 11-17页

作者：冯雪磊肖龙飞寇雨丰上海交通大学海洋工程国家重点实验室上海200240

应用矩和L矩方法以及二次转换方程,基于模型试验数据的概率统计分析,研究半潜式平台在作业工况和生存工况下的气隙响应,以及平台垂向运动对立柱周围不同位置处的波浪升高和气隙的影响。结果表明,垂向运动总体上能够增加气隙,海况越恶劣... 详细信息

应用矩和L矩方法以及二次转换方程,基于模型试验数据的概率统计分析,研究半潜式平台在作业工况和生存工况下的气隙响应,以及平台垂向运动对立柱周围不同位置处的波浪升高和气隙的影响。结果表明,垂向运动总体上能够增加气隙,海况越恶劣,增加程度越明显;在不同浪向下对不同位置的气隙影响有差别,后立柱周围的波浪升高和气隙受平台运动的影响相比前立柱更为显著;同时,平台垂向运动会引起立柱周围波浪升高的非线性增强。

关键词：半潜式平台气隙垂向运动统计分析

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