基于FPM的液舱晃荡研究

随着液舱晃荡运动机理的研究深入,舱内液体运动响应和自由液面波形精细模拟成为研究的重点。本文应用无网格方法中的FPM(Finite Point Method)来对液舱晃荡中的动边界及自由液面大变形等问题进行数值求解和图像模拟。以二维液舱晃荡为例,校核运动边界与内部流体粒子点间的运动响应,得到FPM对于边界所受砰击力和内部兴波波高的计算结果以及自由液面模拟图像。将计算结果进行无因次化处理,通过与试验结果进行比对,验证了FPM在液舱晃荡问题中应用的可行性和准确性,也为FPM解决三维复杂液舱晃荡问题中提供铺垫。     

时域中的潜体兴波研究

从格林定理出发,在边界面上布置Rankine源和偶极子,在时域中用时间步进法计算模拟了潜体近自由面运动的兴波现象,构建了一种处理兴波问题的计算模型.文中详细介绍了这种方法的理论推导和计算过程,并通过试算确定了适当的模型参数.通过对多个参数的变化调整,讨论了它们对潜体兴波阻力和波形变化的影响.大量的数值试验和与试验数据的比较,证实了该法作为三维数值波浪水池的一个支撑模型是可行、可靠的.     

基于CLSVOF方法的多介质流运动界面追踪(英文)

根据Level-Set方法和VOF方法各自的优缺点,耦合生成一种Level-Set和VOF的耦合界面追踪方法,简称CLSVOF(Coupled Level Set and Volume Of Fluid Method)方法。CLSVOF方法利用Level-Set函数计算VOF体积份额,克服了VOF方法难以准确计算界面的法向量和曲率的缺点;同时又利用VOF体积份额修正Level-Set函数,克服了Lev-el-Set方法在计算过程中有物理量的损失的缺点。用旋转流场和剪切流场的数值算例验证了CLSVOF方法相比VOF方法提高了运动界面追踪的分辨率,相比Level-Set方法实现了计算过程中的物理量守恒。运用CLSVOF方法数值模拟了两个多介质流运动界面算例,分别是自由剪切层问题和气泡在静止水体中上升问题.对比数值模拟结果与理论分析和实验结果可知CLSVOF方法能精确地追踪多介质流运动界面。     

基于有限体积法的平面二维水流数学模型的改进

在基于有限体积法的近岸水流数学模型中,单元交界面数值通量的计算精度、潜堤淹没和出露交替的模拟以及动边界技术都是至关重要的。首先通过加入数值通量底坡补偿项对Osher格式的数值通量计算格式进行了改进;又提出单元淹没度的概念,提高了模型在模拟潜堤出露和潮间带干湿变化中的适应性。利用典型算例对模型进行了验证,得到了满意的结果。     

动桨射流数值模拟

船舶航行过程中,螺旋桨推动船体并随之一起运动。为了准确模拟推进过程中的螺旋桨射流,文章区别于常规的稳态分析方法,采用CFD软件FLUENT并基于UDF及动网格技术,对动桨射流进行三维数值计算。其中,湍流通过RNG k-ε模式进行模拟,多相流通过VOF模式进行模拟。并且,文章基于PIV流场测量系统进行了自航船模螺旋桨射流的物模试验,验证了数值计算方法的可行性。结果表明:文章提出的数值计算方法能够较好地模拟动桨射流变化,模拟成果可为研究动桨射流的三维变化过程提供理论依据。     

潜堤掩护港域波浪传播数值模拟

采用基于Boussinesq方程的平面二维波浪数学模型,将潜堤作为动边界处理,对潜堤掩护港域的波浪传播变形进行数值模拟研究。首先,采用Ohyama等的潜堤试验数据,就数学模型对人工潜堤上波浪传播变形问题的适用性进行验证探讨;其次,针对某渔港外部潜堤防护工程,采用数学模型进行波浪场推算,分析潜堤的消浪过程,同时将模拟得出的波浪透射系数与国内外经验公式计算值进行对比,结果表明该数值模拟方法是有效的。     

船舶搁浅于刚性斜坡数值仿真的模型化技术

显式非线性有限元分析已逐渐成为研究船舶搁浅问题的重要方法,但其模型化技术是实现数值仿真的关键。本文将搁浅船处理为可变形结构,用弹塑性材料模拟并进行整船建模,斜坡处理为刚体,用刚性材料模拟,船舶与斜坡之间定义为主从接触,船艏定义为自接触。通过仿真计算,获得并讨论了搁浅过程中的船体运动情况、搁浅接触力曲线、能量转化及船舶损伤变形情况。算例表明本文的模型化技术可以用于船舶搁浅的仿真计算。     

基于滑移网格方法的水陆两栖飞机单船身耐波性数值模拟

针对水陆两栖飞机单船身在规则波浪水面滑行过程中的运动响应大和强非线性等问题,提出一种基于滑移网格方法结合传统动网格方法的耐波性数值模拟方法,有效解决传统动网格方法在水陆两栖飞机水面大幅运动数值模拟过程中的网格严重拉伸和变形问题。通过数值模拟和水池试验,得到水陆两栖飞机单船身在规则波中滑行时的阻力平均值、运动响应双幅值和流场特征,对比数值模拟结果和水池试验结果,两者随波长的变化趋势基本相同,流场特征基本一致,且阻力平均值和运动响应双幅值误差均在10%以内,说明数值模拟精度较高,方法可行。     

波浪作用下斜坡上护面块体应力分布的数值模拟

文章基于SPH方法和FEM/DEM方法建立了SPH-FEM/DEM的二维流固耦合数值模型,模拟了在波浪荷载作用下斜坡上的护面块体内部的应力分布。结构物的水动力条件采用SPH方法模拟,结构物边界采用虚粒子模拟,护面块体结构的受力、运动和变形采用FEM/DEM方法模拟。不同块体间的接触力采用基于势函数的罚函数法来计算,采用中心差分的显式方法来求解有限元单元的变形。应用ANSYS软件和数值模型对静水压力作用下的混凝土方块的内部应力分布进行了比较模拟分析,验证了所建立的耦合数学模型。通过数值计算给出了波浪作用下位于斜坡上的护面块体的动水压力和块体内部的应力分布,讨论了块体内不同角点位置处的应力变化特性。     

基于动网格技术的潜艇热尾流浮升规律研究

针对基于相对运动的"排水法",无法全面、准确地反映潜艇热尾流浮升扩散规律,建立基于动网格技术的潜艇水下航行的二维计算模型,利用流体计算软件Fluent对潜艇排放过程中的流动-传热过程进行数值模拟。采用网格重构和网格光顺方法结合Profile运动边界驱动机制实现网格区域运动,确保模型符合实际运动规律。研究动网格技术和"排水法"热尾流最大浮升高度沿流向分布情况,最大浮升高度和中心温度随时间的变化规律。研究结果表明:动网格技术对于潜艇航行过程中的热尾流浮升过程有较高的计算精度;模拟结果捕捉到了浮升过程中流动和传热的瞬时变化,揭示了热尾流浮升扩散的规律。研究结果进一步为潜艇红外特征研究提供了理论支持和方法思路。     

Errata

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.     

Journal of Marine Science and Application 2014 Sum. Contents

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第34届海洋、离岸及极地工程国际会议(英文)

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;     

33rd International Conference on Ocean,Offshore and Arctic Engineering （OMAE2014）

正San Francisco,California,June 8-13,2014.OMAE 2014 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;·to exchange ideas and experiences whilst promoting technological progress and its application in industry·to promote international cooperation in ocean,offshore and arctic engineering.In line with the tradition of excellence of previous OMAE conferences,more than 900 technical papers are planned for presentation.Outreach for Engineers Specialty Forum This Specialty Forum is designed for students and professionals who may not be familiar with the Ocean and Offshore industry,as well as those who have just recently specialized in this field.     

联合作战计划和执行系统

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。     

Recent progress on wave induced loading measurements in warships

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.     

The 11th International Conference on Hydrodynamics (ICHD 2014)

正19–24 October 2014 SingaporeCONFERENCE THEMES The overall aim of the ICHD Conference is to provide a forum for participants from around the world to review,discuss and present the latest developments in the broad discipline of hydrodynamics and fluid mechanics.The first International Conference on Hydrodynamics(ICHD)was initiated in 1994 in Wuxi,China.Since then,9 more ICHD conferences were held subsequently in Hong Kong,Seoul,Yokohama,Tainan,Perth,Ischia,Nantes,Shanghai and St Petersburg.Evidently the ICHD conference has become an important event among academics,researchers,engineers and operators,working in the fields closely related to the science and technology of hydrodynamics.The 11th ICHD will be held in Singapore in 2014.     

第十二届深水操作会议和展览会(英文)

正November 4-6,2014Moody Gardens HotelConvention Center/Galveston,TX The Deepwater Operations Conference and Exhibition is celebrating its 12th anniversary this year.This growing event will continue the tradition of excellence in addressing operational challenges involved in developing deepwater resources.We will return to the Moody Gardens Hotel and Convention Center on November 5-7,2014 in Galveston,Texas.     

Eastbound or westbound ?

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）.     

Impact of regulation on the performances of long-distance transport services: A comparison of the different approaches in Sweden and Norway

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.