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细长海洋结构物涡激振动研究综述 总被引:5,自引:0,他引:5
随着世界范围内深海石油开采的需要,近年来关于海洋结构物涡激振动的研究越来越受到重视.虽然此问题在数值模拟和实验方面都已取得了一定的进展,但是还有许多问题尚待解决.同时,新型海洋结构物的引入给涡激振动的预报方法和抑振手段提出了新的挑战.因此,细长海洋结构物的涡激振动仍将是未来几年里备受关注的研究课题.本文在介绍有关涡激振动基本概念和理论背景的基础上,总结了近年来关于以深水立管为代表的海洋结构物涡激振动的研究与进展,包括对现有涡激振动分析工具的分类与评估;对柱体及海洋结构物涡激振动的实验研究;对深水立管与涡激振动相关的疲劳评估准则的研究;海洋结构物的横向、流向及轴向涡激振动的耦合作用研究;关于海洋结构物涡激振动的抑振措施和设备的理论及实验研究.本文着重介绍了计算流体力学方法在海洋结构物涡激振动研究中的应用和进展.最后,对海洋结构物涡激振动相关的研究热点的现状进行了总结并对今后工作提出了展望. 相似文献
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顺应式垂直通路立管(CVAR)是目前处于研究阶段的一种新型的立管类型,在海流作用下产生涡激振动,在平台垂荡运动作用下产生参数激励振动。为了研究参数激励的影响,本文引入尾流振子模型模拟漩涡脱落对立管的作用,同时考虑浮式平台升沉运动产生的参数激励,建立了CVAR参激-涡激联合振动方程,获取联合作用下的动力响应,并与纯涡激振动响应进行对比。结果表明,在相同的流速下CVAR中部涡激振动幅值最大,流速的增大会导致涡激振动的频率增大,发生高阶锁振,高阶锁振振动幅值比低阶锁振振动幅值小。考虑参数激励之后,较纯涡激振动而言,立管的振动幅值增大;当参激频率与涡激振动频率接近时,立管的振动幅值最大。 相似文献
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涡激振动是一种在海洋工程领域普遍存在的流固耦合物理现象,易导致海洋立管等结构物发生疲劳损伤或失稳。本文为抑制涡激振动而提出一种附加轴向板条的方案,采用非定常流体数值计算方法求解分析不同分布形式下的轴向板条对海洋立管涡激振动特性的影响。首先定义轴向板条的分布形式;采用Newmark-β法求解立管双自由度振动方程并编写UDF,计算采用k-ω/SST湍流模型,并结合动网格技术模拟立管的振动过程。研究结果表明,轴向板条对海洋立管具有较好的抑振效果;当轴向板条数目n=20时,流向振动幅度减小78.57%,横向振动幅度减小58.10%。本文研究结果可为海洋结构物涡激振动的抑振提供参考。 相似文献
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针对分隔板、控制杆和减振器3种抑振装置对串联立管涡激振动的抑制效果问题,在波流水槽中进行不同间距下串联立管的裸管试验以及抑振管涡激振动试验。试验结果表明,在同一流速条件下,附加抑振装置后立管的振动振幅与裸管相比明显降低,所采用的3种抑振装置可不同程度抑制海洋立管的涡激振动。对于横向振动最优抑制效果来说,控制杆的最优抑制效果最好;对于顺流向振动最优抑制效果来说,分隔板在上游立管中的最优抑制效果最好,控制杆在下游立管中的最优抑制效果最佳。综合比较各间距与振动方向的最优抑制效果,控制杆能够对串联立管横向与顺流向的振动起到不错的抑制效果。 相似文献
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顶张力对深水刚性立管涡激振动及疲劳损伤的影响 总被引:1,自引:1,他引:0
分析讨论顶张力对深水刚性立管在剪切流中的涡激振动响应和疲劳损伤的影响。从理论上分析张力对刚性立管固有特性的影响,并利用OrcaFlex软件建立数值模型,模拟不同顶张力系数下立管于剪切流中的涡激振动响应,同时采用S-N曲线法计算立管疲劳损伤。结果表明,顶张力对立管的影响直接体现在刚度上,立管刚度随着张力的增大而增大,因此顶张力对降低立管疲劳损伤有一定积极作用。但是随着顶张力的增大,其对降低疲劳损伤的贡献越来越小,而对立管强度储备的危害却逐渐增大。 相似文献
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《船舶与海洋工程学报》2014,(2)
正In the paper"Influence of Fouling Assemblage on the Corrosion Behaviour of Mild Steel in the Coastal Waters of The Gulf of Mannar,India"in Vol.12,No.4,Page:509,References were lost,and the two authors’biographies were identical.The correct text is shown below.We apologize to the authors and our readers for any inconvenience caused by the errors. 相似文献
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《船舶与海洋工程学报》2014,(4)
正St.John's,Newfoundland,Canada,May 31-June 5,2015 OMAE2015 is the ideal forum for researchers,engineers,managers,technicians and students from the scientific and industrial communities from around the world to: meet and present advances in technology and its scientific support; 相似文献
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联合作战计划和执行系统 总被引:2,自引:1,他引:1
全球指挥控制系统(GCCS)实施当前美国海军网络中心战信息基础设施的联合计划网络。联合作战计划和执行系统(JOPES)支持GCCS实现联合计划。JOPES有两类计划:时间不限的精密预案计划生成作战计划、方案计划或职能计划;时间敏感的危机行动计划生成作战命令或战役方案。前者在和平时期创建的作战计划是后者的计划基础,加速应付危机的能力。 相似文献
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In terms of equal sailing distances, where is the inflexion when ships depart from ports in the Asian Continent to New York via Suez and/or Panama?
The answer is China South Port Group (Hong Kong, Shenzhen and Guangzhou). 相似文献
The answer is China South Port Group (Hong Kong, Shenzhen and Guangzhou). 相似文献
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Recent measurements of wave induced hull strain and flexure in RN warships are presented together with the derivation of the current design criteria for extreme hull girder bending loads. The history of the development of the shipboard instrumentation used is given and recent developments to improve the quality and ease of analysis of the data are described. An unexpectedly high transverse asymmetry in the longitudinal strains measured in destroyers is shown to be the result of a combination of vertical and lateral bending in oblique seas. Finally recent theoretical comparisons between the loading of Deep-Vee hulls and conventional UK rounded bilge hulls are presented which demonstrate the higher loading experienced by this type of hull form. 相似文献
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桥梁防撞设施物理模型试验 总被引:1,自引:0,他引:1
物理模型试验是预报防撞设施所受撞击力及优化设计方案的主要方法之一。结合杭州湾大桥柔性防撞设施及东海大桥独立式防撞体设计方案,阐述了船—防撞体撞击试验的基本原理、方法、试验方案及相关试验结果。提出了柔性防撞系统的优化方案。试验结果表明,该方案经济有效,可供预报类似桥梁防撞设施撞击力时参考。 相似文献
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印尼某电厂项目码头水工建筑物包括码头、防波堤和护岸等主要组成部分。在该项目水工建筑物的设计过程中,综合考虑当地的自然条件、施工能力和材料来源等因素,不断优化结构选型和结构断面。根据不同使用要求,护岸分别采用直立式和斜坡式2种结构型式,推荐的设计方案节省投资、施工方便,可供同类工程设计参考。 相似文献
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Gunnar Alexandersson Staffan Hultén Frode Longva 《Research in Transportation Economics》2010,29(1):212-218
Despite the many socio-economic similarities between Sweden and Norway, differences in jurisdiction, organisation, cooperation, and financing of long-distance passenger train and coach services have led to the development of four distinctively different ways of serving the markets. This paper describes how the train and coach markets have developed in the two countries, with emphasis on regulatory and industrial structure and a couple of performance variables.Looking at passenger rail, both countries separated infrastructure from operation over a decade ago. However, while Norwegian rail is characterised by an almost monopoly supplier, rail services in Sweden are partly decentralised to the responsibility of county authorities and are widely subjected to competitive tendering. The rest of the network is about to be opened up for on-the-track competition. Swedish Rail (SJ) has spent the last decades consolidating its core business (passenger rail) and sold out its other businesses. In contrast, the Norwegian state rail (NSB) has expanded its business to become a major bus operator and property owner, with extensions also into the Swedish market.The coach industry was more recently deregulated in both countries. The Swedish coach market is dominated by privately owned companies operating services to and from Stockholm. In Norway, state-owned NSB is a major coach operator on medium distance routes, and is also the largest partner of Nor-Way Bussekspress which totally dominates long-distance coach services. Further, the Norwegian coach market is characterised by cross-ownership and cooperation which has enabled an extensive route network which covers most of Norway.We find distinct differences in achievements in the two modes and in the two countries. Swedish rail services have succeeded in winning market shares and in renewing and developing both infrastructure and service levels to a greater extent than the Norwegian model. On the other hand, the Norwegian coach market seems to be more developed and efficient compared to its Swedish counterpart.The paper concludes with a discussion on the possible links between the different approaches and the performance observed, with the aim to stimulate further and more detailed research on some important issues. 相似文献