水下悬浮隧道锚索稳定性分析

为研究水下悬浮隧道锚索的稳定性,建立锚索在涡街激励作用下振动的数学方程,采用伽辽金法对其进行化简,锚索振动的稳定性通过Lyapunov指数法进行判断,分析了锚索动静张力比的大小、悬浮隧道系统的阻尼比和锚索参数激励频率对锚索振动稳定性的影响。计算结果表明,锚索振动失稳的范围取决于锚索的动静张力比、锚索的阻尼比和频率比(锚索参数激励频率与锚索1阶模态固有频率的比值);当频率比为1和2左右时,随着锚索动静张力比的增大和阻尼比的减小,锚索逐渐从稳定状态转变为不稳定状态,且锚索的不稳定区域逐渐增大。     

智能材料在水下仿生机器人驱动中的应用综述

基于智能材料的柔性仿生水下机器人的研究是当今水下机器人研究的热点之一。智能材料驱动的水下仿生机器人具有微型化、柔性化、智能化、低噪声以及易于主动产生复杂运动等特点,其外形结构更加符合生物学特性,和传统驱动方式相比具有较大的优越性,近年来在水下机器人领域得到了较快的发展。本文对几种应用于水下机器人中常见的智能材料的驱动原理进行了比较,在此基础上介绍了国内外近年来利用上述几种智能材料作为驱动器研制的各种机器人。对机器人的外形结构和驱动模式作了简要介绍,重点对机器人驱动效率进行了分析和比较,分析了几种驱动材料性能的优劣。最后,指出了当前仿生水下机器人发展存在和需要解决的问题。     

水下全自动显微成像仪

介绍了水下全自动显微成像仪的原理、关键设计和现场试验情况.该仪器有效地解决了水中采样技术,可用于1～100μm悬浮颗粒的现场图像拍摄,工作水深达100 m.利用该仪器拍摄到了现场悬浮颗粒图像,利用这些图像可以分析悬沙颗粒分布,同时也可以检测浮游生物,研究赤潮.     

基于多波束数据的港珠澳大桥隧道基础检测分析

介绍了港珠澳大桥沉管隧道碎石基础结构测量控制内容,针对沉管隧道水下标高测量精度高的特点,通过对多波束测深数据的对比分析,验证了测深数据的精度及可靠性。并基于多波束数据量大、相对精度高的优点,提出特制单波束数据与多波束数据相结合的水下标高点面控制法和深水深槽结构物尺寸图上测量法,实现了沉管隧道碎石基础质量全面控制,并为管节安装快速决策提供依据。     

辽东湾北部浅海区现代冲淤动态分析

通过对辽东湾北部浅海区现代动力分析，本文对该区岸线变化、潮滩冲淤以及水下动态进行了初步分析。用细粒级沉积物堆积的沉积延迟效应理论论来解释该区西部岸线向海推移和潮滩淤积。水下部分－１—－３ｍ处为波浪破碎区和潮流强烈作用区，受到侵蚀和冲刷，并且悬浮的泥沙几岸和深水区运移，形成两个稳定堆积区。     

黄河口水下三角洲海底冲蚀沟发育的动力机制探讨

根据老黄河口外水下三角洲海底冲蚀沟的地貌特征,用动力学方法分析了其形成发育机制.结果表明,波浪近底流是冲蚀沟形成发育的主导因素.冲蚀沟内的湍流及其次生的横向环流构成了复杂的流场,由此产生的边界切应力对冲蚀沟的侵蚀及沉积物的悬浮、扩散起重要作用.冲蚀沟的断面形态与流场结构密切相关.     

水中悬浮隧道锚索参数振动分析和控制

为了进一步研究水中悬浮隧道锚索的参数振动以及振动控制,考虑到流的影响,建立水中悬浮隧道锚索的非线性振动模型,并利用数值方法推导求解了锚索的非线性振动方程,同时采用一种被动质量阻尼器进行振动控制。研究结果表明:锚索的参数振动与锚索的初张力、参数激励幅值、频率比有关,并具有明显的非线性特征;流的作用会对锚索的参数振动幅值产生一定影响,但流的作用不会改变锚索的共振规律;对锚索参数振动提出的振动控制装置,计算结果表明具有良好的减振效果。     

三沙永乐龙洞悬浮体垂直分布特征及其影响因素

为研究中国唯一已知、全球最深海洋蓝洞的形成、发育和演化机制,应用LISST-100X现场激光粒度仪、CTD温盐仪等搭载工作级水下机器人,于2017年5月在三沙永乐龙洞进行了悬浮体、温盐剖面测量,获得了全洞深的悬浮体体积浓度、温盐和溶解氧等数据,并进行了悬浮体垂向分布特征研究。研究结果表明,洞内90 m以下水体为无氧环境,悬浮体浓度呈现5个变化旋回,温度、盐度均存在3个跃层,并且它们之间有着较好的对应关系。龙洞内水体表层悬浮体总浓度约为20 μL/L,悬浮体平均浓度值为5.93 μL/L。悬浮体旋回层Ⅰ位于5 m以浅水层;旋回层Ⅱ位于10～43 m之间,与第一个温盐跃层(深度10～20 m)部分对应;旋回层Ⅲ位于70～110 m之间,与第二个温盐跃层(深度70～110 m)完全对应;旋回层Ⅳ位于130～150 m之间,与第三个温盐跃层(深度130～150 m)完全对应;旋回层Ⅴ位于260 m以深至洞底300 m。龙洞表层悬浮体浓度较高,主要是受到洞外周边珊瑚礁松散沉积物输入的影响。洞内悬浮体垂直分布特征主要受到水动力、洞体形态、温盐跃层、溶解氧含量以及浮游生物等的控制和影响。     

冬、夏季东海北部悬浮体分布及海流对悬浮体输运的阻隔作用

依据1987年6月、1996年12月、1997年2月和1998年7月在东海北部所取得的悬浮体、温度和盐度资料就该区冬季和夏季的悬浮体分布、影响因素和输运进行了研究,结果表明该区悬浮体分布具有明显的季节性变化,在中、外陆架区悬浮体含量冬季明显高于夏季.悬浮体的分布及输运受到东海环流、风暴和潮流等的影响,其中东海环流的季节性变化是主要影响因素.受台湾暖流的阻隔,冬季和夏季长江入海泥沙在东海基本不能越过124°00'E以东海域.黄海沿岸流携带着老黄河口水下三角洲的再悬浮沉积物向陆架东南扩散,其搬运的量和在中、外陆架区的扩散范围冬季显著大于夏季.在黄海暖流的阻隔下,陆架悬浮体冬季和夏季在32°N断面很少能扩散至126°30'E以东海域.台湾暖流和黑潮爬升水的阻隔作用使得冬季和夏季陆架悬浮体在P-N断面也基本不能扩散至陆架边缘.冬季在东海北部可有部分陆架悬浮体输送到冲绳海槽,但有区域性,其输送的可能位置是在P-N断面以北、32°N断面以南之黄海沿岸流向东南延伸的陆架边缘;夏季陆架悬浮体基本滞留在陆架区.     

基于电动螺旋的可控水下吸附结构模型设计

牢固可靠的水下生根是提高水下机器人(ROV)作业效率的关键。首先对步进电机-滚珠丝杠驱动负压吸附结构进行了研究,设计了一型可用于水下负压吸附的内部充油双对置活塞结构,并对提高端面密封性能的多唇边密封结构进行了形状设计,其次推导了实现可控吸附结构的力学模型并进行了计算分析,最后建立了可控水下负压吸附结构功能实现的流程。研究结果可为水下可控可靠吸附结构的硬件实现提供参考。     

Coupled analysis of floating production systems

Fully coupled global analysis of Floating Production Systems, including the vessel, the mooring system and the riser system is described. Design of the system can be a daunting task, involving more than 1000 load cases for global analysis. The primary driver for the mooring system and for the riser system is motion of the vessel. Vessel motions are driven by environmental forces, but are restrained by forces from the mooring and riser systems. Numerical models and procedures that provide accurate and efficient global modeling of the Floating Production System are presented. Both Time Domain and Frequency Domain procedures are included. The accuracy and efficiency of the procedures are illustrated in an example: a large semi with 16 mooring lines and 20 risers. The procedures provide the accuracy and efficiency for use of fully coupled analysis in design of Floating Production Systems from concept selection to final design, installation and operation.     

远海浮式结构物与供应船旁靠系泊特性研究

针对远海浮式结构物与供应船进行旁靠作业时,水动力干扰、两船的相对运动、旁靠系缆系统和护舷系统的受力特征等问题开展研究。建立各船的有限元模型,设计出两船旁靠连接缆系统,选取合适的系泊缆和护舷参数。研究表明:浮式结构物和供应船的横荡、纵荡方向存在一定的同步性或跟随性,幅值相差不大,其它方向的运动并不存在明显的同步特征;供应船的各自由度运动幅值均比浮式结构物偏大;旁靠护舷的受力时历出现了明显的低频效应,说明护舷的受力较大程度上受船体低频慢漂运动的影响;浮式结构物对供应船的水动力干扰较大,当浮式结构物在供应船的上风位置时,表现为屏蔽效应,供应船的运动较小;在其背风位置时,运动加剧,出现多次共振、峰值放大现象,供应船对浮式结构物的水动力性能几乎无影响,因此,供应船从浮式结构物的下风口一侧靠泊作业将更有利于船舶的安全性能。这些研究结论可为实际工程操作提供参考。     

Fluid-structure interaction response analysis of floating nuclear plants including the effects of mooring

The accelerated growth in the offshore oil exploration, the rapid escalation of oil prices, and the growing concern on the environmental effects of land based nuclear plants should considerably increase the confidence in the offshore Floating Nuclear Plant (FNP) concept.The paper presents the state-of-the-art on the dynamic analysis of FNPs from the viewpoint of fluid-structure interaction effects. The topics covered include the dynamic analysis of the sub-systems, namely, (1) basin oscillations, (2) floating platform supporting the power plant, and (3) mooring systems. Application of the finite element technique is illustrated, and the hydrodynamic results obtained by various authors are discussed.     

Transmitted and reflected coefficients for horizontal or vertical plate type breakwater

Surface or submerged horizontal or vertical plate can be considered as a new concept breakwater.This paper investigates the wave-plate interaction of this type of breakwater by use of the boundary element method.The relationships of wave transmitted and reflected among plate thickness,submergence and length are carefully studied by numerical simulation.It is shown that:(1) The transmitted coefficients of submerged horizontal plate or vertical plate will become larger with the increase of plate thickness and reduce rapidly with the decrease of plate submergence.(2) Both surface horizontal and vertical plate are efficient for intermediate and short wave elimination,but vertical plate is more effective.(3) Submerged horizontal plate can act more effectively than submerged vertical plate does.With all wave frequencies,the vertical plate almost has no wave elimination effect.     

Environmental factors influencing macrodetritus flux in North Inlet estuary

Floating macrodetritus transport was determined on 72 tidal cycles over 18 months. Floating macrodetritus was exported from the marsh-estuarine ecosystem to the Atlantic Ocean, but export was low (less than 1% of Spartina net aerial primary production). Season and processes within the system seem to determine ebb flux, while flood flux is best explained by a semi-lunar cycle or high water. The extensive observations reported here indicate macrodetritus probably should not be considered a major source of organic carbon export from marsh-estuarine systems.     

Extreme value analysis in a multivariate offshore environment

Floating offshore systems are exposed to a multivariate environment with wind, waves and current all making a significant contribution to the mooring forces. The design of such systems requires an appreciation of the extreme conditions but the concept of the return period value has to be extended to reflect multiple environmental variables. This study examines the practicalities of employing a multivariate point process model in extreme value analyses, using a moored semi-submersible and its responses to the wind and waves as an example. The output from this illustrative bivariate analysis includes both estimates of the 50-year mooring force and also return period contours which indicate the likely combinations of wind and wave which might give rise to the 50-year condition.     

Socioeconomic Impact of the Taiwan Strait Tunnel

This article discusses the possible socioeconomic impact of Taiwan Strait Tunnel from the perspective of the relationship between the construction of Taiwan Strait Tunnel and the socioeconomic development of the two sides of the Taiwan Strait and the surrounding areas. First of all, the construction of Taiwan Strait Tunnel in its conceptual stage depends on the socioeconomic development of the two sides of the Strait. Important basic conditions—such as the mainland's and Taiwan's future sustainable economic growth above what has already been achieved; their further development of economic, trade, and social ties; their political dialogue based on “the principle of one China”; and the progress of the peaceful reunification of the motherland—will decide the construction of the Taiwan Strait Tunnel. Under such conditions, once the Taiwan Strait Tunnel is operable, it will create a huge demand pull on the two sides of the Taiwan Strait and their surrounding areas for a long period and, thus, will bring about a sustainable increasing economic upsurge in the two sides. Secondly, once the Taiwan Strait Tunnel is open to traffic, its transport ability will be tremendous and will greatly influence the economic development of the two sides of the Strait and enhance their economic and trade ties and their personnel exchange. At the same time, the tunnel will not only form a new traffic pattern of the two sides of the Taiwan Strait, but it will also improve their traffic structure and expand their traffic scale to a large extent. It is certain that the construction of Taiwan Strait Tunnel will be a highly complex project of an all-time grand scale to be constructed over quite a long period. It will encounter a lot more restrictive factors than have ever been met in the fields of design, programming, techniques, equipment, organization of construction, and the operation and maintenance of the tunnel and line. Moreover, it will also encounter many important restrictive factors as a result of its socioeconomic impact.     

Early Stage Characteristics of Macro Engineering and Suggestions for the Taiwan Strait Tunnel Project

Taiwan Strait Tunnel (TST) is a Macro Engineering Project (MEP). Countries all over the world have accumulated much experience on MEPs. To study the early stage characteristics of MEPs would be significant for advancing the progress of TST project. This article summarizes some common characteristics in early stage of MEPs, such as Three Gorges, South-to-North Water Diversion, The Channel Tunnel, Confederation Bridge projects, and so on. Some suggestions on early stage development are given to TST project for reference.     

Early Stage Characteristics of Macro Engineering and Suggestions for the Taiwan Strait Tunnel Project

Taiwan Strait Tunnel (TST) is a Macro Engineering Project (MEP). Countries all over the world have accumulated much experience on MEPs. To study the early stage characteristics of MEPs would be significant for advancing the progress of TST project. This article summarizes some common characteristics in early stage of MEPs, such as Three Gorges, South-to-North Water Diversion, The Channel Tunnel, Confederation Bridge projects, and so on. Some suggestions on early stage development are given to TST project for reference.     

Jurisdiction and offshore petroleum in Australia: creating symmetry between the Commonwealth and states by sharing benefits and avoiding costs

This article examines the federal legislative regime for governing offshore oil development in Australia. Adopting an evolutionary perspective, the article considers how the Australian petroleum regime has been able to avoid the ‘asymmetry of costs and benefits’ which have shut down the offshore oil leasing program on the US west coast. To this end, it is shown that the Petroleum (Submerged Lands) Act has overcome jurisdictional issues by creating a partnership between the federal and state governments, enabling both to share in the benefits of policy making. This joint decision-making structure is narrowly focused upon exploitation, though, and does not deal with environmental issues outside of its original scope. The absence of a complementary regime to fill this policy gap permits environmental costs to go unaccounted in petroleum development. This shortcoming notwithstanding, the Petroleum (Submerged Lands) Act provides a useful model by which federal/state jurisdictional limitations can be overcome. Ocean and coastal issues are currently receiving political attention in Australia, and it is timely for the cooperative governance model to be revisited and also extended to other marine policy sectors. Moreover, joint authority approaches could be considered by other federations struggling with offshore jurisdiction issues.