水中气泡幕对噪声的屏蔽效果研究

本文基于水中气泡幕对宽频带噪声有良好衰减和屏蔽作用的基本原理,阐述了水池船模气泡幕降噪实验所取得的一些研究成果,其中包括喷气管布置方式、喷孔直径、喷气量等不同时的降噪量对比、喷气环截面形状与阻力的关系等.研究表明,喷气管分散布置方式时噪声的屏蔽效果较好;梯形截面喷气环的阻力明显比半圆形截面小;在实验所取喷孔直径及喷气量范围内,开孔直径和船模速度的改变亦对其屏蔽效果有较大影响.     

化学药剂产生气泡幕模拟舰船尾流分析

介绍了如何利用化学药剂与水反应生成气泡幕模拟舰船尾流。只有当模拟尾流的声强度和真实舰船尾流的声强度相同或者相近时才有可能成功对抗尾流自导鱼雷,而模拟尾流的声强度和单位体积气泡含量相关。本文从气泡幕单位体积气泡含量和气体含量以及所需化学药剂量三个方面对此方法进行了分析。     

气泡帷幕对圆柱状壳体防护效果的实验研究

运用实验的方法研究了气泡惟幕对于圆柱状壳体的实际防护效果和气泡帷幕衰减水中冲击波的频谱特性．     

气泡幕后向散射信号中的多次散射效应研究

利用蒙特卡罗方法对气泡幕后向散射接收信号及其各次散射分量进行了系统仿真,并详细讨论了不同接收视场和气泡幕密度下的多次散射效应.结果表明:高次散射信号在气泡幕回波信号中占有重要的成分.不能以单散射来近似计算;随着接收视场和气泡幕密度的增加,高次散射分量在接收信号中的比重增加,有利于气泡幕后向散射信号的探测.     

多排式气幕防波堤消浪性能数值模拟研究

基于CFD工具,以不可压缩雷诺平均N-S方程、k-ω SST方程为控制方程,利用VOF方法追踪气液两相流界面,建立数学模型,对气幕防波堤的消浪性能进行研究,通过对比透射、反射系数,数值模拟计算结果与物理模型试验结果吻合良好。在此基础上,讨论了静水中不同气幕排数及间距下气幕周围的流场特性,进而分析了气幕排数及间距对不同周期波浪消浪效果的影响。结果表明当供气量较大且其间距为单排气幕两侧最大水平流流速之间的距离时,双排式气幕防波堤能有效增加其消浪效果,尤其是可以增大对较长周期波浪的消浪效果,但当气泡帷幕增加到三排时,其消浪效果由于供气量的分散没有显著提升。该研究结果为气幕防波堤在实际工程中的设计和应用提供了理论支持。     

气泡帷幕对港口水域爆破波的削弱

气泡帷幕技术可以削弱水下爆破产生的冲击波而受到广泛的关注,目前对气泡帷幕的研究大多局限于规则水域,对实际施工中复杂水域的研究较少,并且没有考虑到横向水流对气泡帷幕偏移的作用等。利用ANSYS/LS-DYNA对港口水域水下钻孔爆破进行了数值模拟,分析了气泡帷幕对冲击波的峰值压力和冲量削弱特性,通过与经验公式计算的规则水域中峰值压力的衰减特性对比,验证了本文所采用的数值模拟方法的合理性。研究结果表明:设置两层气泡帷幕时,气幕间距越大,气幕对冲击波的削弱作用越强;水流速度越大,气幕偏转的角度越大,其防波特性越好。     

国内外船舶气泡减阻技术的研究与应用

介绍国内外船舶气泡减阻技术的研究情况,包括微气泡减阻技术、气幕减阻技术及气膜减阻技术的试验研究和理论计算结果,特别是俄罗斯倾斜板气泡减阻技术、日本微气泡减阻技术和我国薄层气膜减阻技术的特点。同时,介绍国内外微气泡减阻理论方面的力学模型、数值计算方法和重要结论。回顾20世纪60年代以来气泡减阻技术在船舶上的应用情况,特别是俄罗斯、日本及丹麦等国设计的气泡减阻船舶的性能和节能效果。针对我国目前气泡减阻节能技术在实船上的应用现状,分析存在的问题和不足,探讨我国船舶气泡减阻技术的应用前景。     

动水中气幕围油栏围油性能数值模拟

气幕围油栏利用气泡幕在水面形成的表面流和气泡破裂隆起高度实现围油。为对动水中气幕围油栏的围油性能进行研究,采用VOF(Volume Of Fuid)方法追踪油污和水的界面,以变密度单流体的连续性方程和κ-ε方程为控制方程建立动水中气幕围油栏的数学模型。首次引入有效围油距离D,通过监测有效围油距离并结合流场分析,探究围油过程。数值模拟结果与试验结果吻合较好,证明了动水中气幕围油栏围油的可行性。通过数值计算结果对比分析得出了动水中影响气幕围油栏围油性能的主要因素,对气幕围油栏的研发具有重要意义。     

钦州港西航道拦门沙开挖回淤研究

采用实测资料分析与公式计算相结合的方法,对钦州港西航道拦门沙开挖后的回淤进行了研究,研究结果表明,拦门沙较为稳定,外域无沙源,影响挖槽回淤的主要因素是滩地风浪掀沙。由于滩地为中、细沙组成,大风浪出现机遇较少,因而年均回淤量不大,航道稳定性良好。     

电解水式驻留微气泡减阻技术及其可行性分析

在通常的气幕减阻技术中,由于气泡的不断流失容易产生能耗增大、减阻效果下降等问题。该文提出一种利用驻留微气泡的减阻技术。微气泡产生于阵列布置于航行体表面的微凹坑中,并在航行过程中稳定驻留于凹坑处,从而有效降低局部摩阻系数;微气泡通过电解水产生,并可反过来对电解反应进行自适应控制,从而自适应地控制供气量和气泡形状。通过初步数值模拟和实验,对影响气泡驻留的因素进行了定性的分析。设计了一种电解反应自适应控制的凹坑结构,用于气泡形状和电解反应的自动控制。通过数值计算,对一特定条件下驻留微气泡的理论减阻能力进行了讨论。     

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;     

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。     

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）.     

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.     

桥梁防撞设施物理模型试验

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。     

印尼某电厂码头水工建筑物设计

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。     

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.     

开放式数据挖掘系统模型

目前国内已经出现了少量的数据挖掘相关产品。国内数据挖掘软件无论从数量还是质量上比较，都与国外软件存在着较大的差距。随着数据仓库技术的普及，数据挖掘应用的需求越来越强烈，如何缩短这种差距，研发数据挖掘软件产品成为国内业界的一个重要问题。通过引用目前国际通用数据挖掘标准技术来构建开放式的数据挖掘系统模型，该系统模型从可扩展性、可重用性、易用性等方面得到了加强。