两种尾部附体在过渡型船舶上的对比研究

为了研究阻流板和压浪板在过渡型船舶上的适配性,对某过渡型船舶进行了安装节能附体前后的阻力试验及数值研究。探讨了压浪板下反角α=5°,10°以及15°时的船舶水动力性能,并结合前期的阻流板研究成果,对两种附体的适配性进行了对比研究。结果表明:STAR-CCM+可以对船舶阻力进行准确预报,并能较好地捕捉方尾船的尾流场特征;0.334≤Fr≤0.584时,压浪板(10°)能够使船模阻力平均降低6.54%,其中Fr=0.4时,减阻率最高可达8.61%。压浪板(10°)对船舶尾流场的改善更加显著,但其附体阻力要高于阻流板(Z2);综合结果:当Fr≤0.5时,压浪板(10°)的减阻效果更好;当Fr0.5时,阻流板(Z2)的减阻效果更优。     

基于高速三体船阻力性能的压浪板参数敏感性分析

为了研究不同外形和安装位置的压浪板对高速三体船阻力的影响，选取了展长B、弦长L、安装角度θ、主体安装高度H及侧体安装高度h等5个代表性参数，通过正交试验设计出16种参数组合，采用基于雷诺时均方法的SST k-ω湍流模型对加装不同压浪板的三体船静水航行过程进行数值模拟并验证模拟的准确性，极差分析得出5个参数对总阻力系数的影响顺序为H>h>B>L>θ。对较优参数组合压浪板进行多航速模拟，并监测静水阻力、纵倾、艉下沉、自由液面及船底压力等数据，分析压浪板减阻和改变航行姿态的原因，发现减阻效果随着航速的增大而逐渐明显，傅汝德数Fr为0.598时减阻率可达12.69%。     

二维扁卵形体近壁面水动力干扰实验

对长度-厚度比为7.0的二维扁卵形体近平壁面运动的水动力特性进行了研究.拖曳水池试验选择了六种不同的壁面间距,五个攻角状态,将卵形体模型安装在U形槽中,保证流场的二维特性.Reynolds数范围从5×105到2×106.根据无界流实验结果,在数据处理中消除测力天平的安装角误差.给出了水动力系数相对于间距、攻角的回归公式,并划分了三个典型的干扰区域:升力区、混合区、阻塞区.实验表明:即使对于钝尾物体,也存在类似机翼的升力效应,无界流中扁卵形体的升力线斜率小于二维平板机翼的相应值.当物体离壁面较远时,水动力系数随攻角线性变化,壁面影响随间距减小而增大;当物体离壁面很近时,出现排斥现象,水动力系数随攻角的变化呈非线性特征.与其它参数相比,在大部分试验状态下,运动速度对水动力系数的影响较小.     

尾缘开槽的环量控制舵翼性能试验研究

本文介绍了一种展弦比为１的环量控制舵翼在零攻角下的水动力性能试验，试验模型是安装有尾缘喷流圆柱的ＮＡＣＡ００１５截尾方形舵。试验结果表明，随喷流动量系数的增加，升力系数显著上升，为减小阻力，在模型尾缘圆柱上开了一排Ｖ形槽，开槽后的模型阻力有不同程度的降低，并用喷流动量系数越大，减阻减大。开槽的另一个效果是使喷流失速推迟。     

基于SPIV的压浪板对DTMB5415船模尾流场影响的试验研究

以DTMB5415船模为研究对象,基于体视粒子图像测速技术(Stereoscopic Particle Image Velocimetry,SPIV)对压浪板安装前后的船模伴流场及尾流场中多个截面进行测量。PIV测量对船体边界层内流动进行了很好的捕捉,与国际上公开的相关流场信息具有较高的吻合度,补充了DTMB5415基准船模的流场数据库。压浪板的安装会降低桨盘面速度,且压浪板的影响会随着船舶航速的增大而增大,在Fr数为0.28和0.41时,桨盘面平均速度分别降低了0.77%和1.45%。此外,压浪板对流场测点的影响随着距离的减小而增大,在X/L_(PP)为0.95、0.97和0.99这三个截面上的平均无量纲轴向速度分别降低了0.009、0.027 3和0.045 9。     

尾压浪板对高速艇阻力性能的影响

在高速艇上采用尾压浪板后,对减少艇体阻力常会得到较满意的结果。本文主要介绍上海交通大学船模试验池的有关试验结果,并分析了尾压浪板对艇体阻力的影响。得出以下几点结论:(1)排水量长度系数 C_D=D/((L/10)~3)是影响压浪板减阻效果的主要参数,当C_D>2.0,采用尾压浪板一般可收到减阻效果。(2)在 C_D≥2.0的范围内,高速排水量艇采用压浪板后所能得到的阻力收益大体可按下式进行估算:(ΔR_T)/(R_T)(%)=1.6 1.45C_D(3)尾压浪板的长度以船长的1～2%为宜。     

压浪板与游艇航态及阻力性能关系的研究

安装压浪板会在游艇艉部形成局部高压区,产生附加水动升力从而改变游艇的航行姿态,并影响游艇的阻力性能。采用半理论半经验方法分析安装压浪板前后游艇的姿态及阻力变化,研究压浪板对游艇产生影响的作用机理以及二者之间的匹配关系;获得压浪板最佳尺寸及安装角度的计算方法。结合方艉尖舭型游艇实例,验证压浪板在工程应用中的价值。     

船体尾压浪板砰击载荷分析

本文针对尾压浪板入水砰击压力开展研究,分别用Fluent和Dytran软件计算其入水砰击载荷。本文首先在不同的有限元模型中计算尾压浪板以10 m/s入水时的砰击压力,选择具有合理网格尺寸的有限元模型,进而避免了网格尺寸对计算结果的影响;接着分别计算了尾压浪板以不同速度入水时所受到的砰击压力,二者计算得到的砰击压力系数与我国规范给出的结果较为吻合,对于船舶尾压浪板砰击载荷的选取具有一定的参考意义。     

船用首升力体水动力影响分析研究

首升力体技术已被CFD、缩比模型试验、实船试验证实,在零航速与有航速情况下均可降低船舶运动,提高船舶耐波性.本文采用VOF方法捕捉自由液面,对有自由液面情况下,不同攻角、不同浸深和不同航速的首升力体,计算了首升力体的升力、阻力和自由面兴波等.     

共型舵翼缝隙对水动力性能与流场的影响

为了研究舵-翼之间缝隙对共型舵水动力性能与流场的影响,开展了水筒和风洞试验。试验结果表明缝隙窜流使舵的升力系数大幅降低,还使翼型尾流不均匀性及湍动能显著增强。结合数值模拟方法,进一步研究缝隙宽度对舵的升力以及尾流场的影响,并对缝隙形状进行了优化设计。优化后的翼型升力提升了6.8%以上,尾流场也得到了改善。     

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.     

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.     

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.     

Catalyzing Coastal Management in Kenya and Zanzibar: Building Capacity and Commitment

Site-based projects were initiated in Chawka Bay-Paje, Zanzibar, and Nyali-Bamburi-Shanzu, Kenya, to demonstrate the benefits of an integrated coastal management (ICM) approach for addressing coastal issues such as tourism development and enhancement of resource-dependent village economies in eastern Africa. A two-year, multidonor project used three primary strategies to make rapid, but sustainable, progress toward ICM. These included using interagency government teams for ICM planning, adopting an internationally recognized framework for ICM as a project ''road map,'' and explicitly incorporating capacity-building strategies into all aspects of the project. Within two years, integrated ICM action strategies, prepared through participatory processes, were being implemented at both sites, and both teams were working to expand the scale and scope of ICM in their nation. More importantly, the project helped create committed, capable, interagency groups that continue to work together to address urgent ICM issues.     

A simplified method for reliability- and integrity-based design of engineering systems and its application to offshore mooring systems

This paper presents a simplified method for the reliability- and the integrity-based optimal design of engineering systems and its application to offshore mooring systems. The design of structural systems is transitioning from the conventional methods, which are based on factors of safety, to more advanced methods, which require calculation of the failure probability of the designed system for each project. Using factors of safety to account for the uncertainties in the capacity (strength) or demands can lead to systems with different reliabilities. This is because the number and arrangement of components in each system and the correlation of their responses could be different, which could affect the system reliability. The generic factors of safety that are specified at the component level do not account for such differences. Still, using factors of safety, as a measure of system safety, is preferred by many engineers because of the simplicity in their application. The aim of this paper is to provide a simplified method for design of engineering systems that directly involves the system annual failure probability as a measure of system safety, concerning system strength limit state. In this method, using results of conventional deterministic analysis, the optimality factors for an integrity-based optimal design are used instead of generic safety factors to assure the system safety. The optimality factors, which estimate the necessary change in average component capacities, are computed especially for each component and a target system annual probability of system failure using regression models that estimate the effect of short and long term extreme events on structural response. Because in practice, it is convenient to use the return period as a measure to quantify the likelihood of extreme events, the regression model in this paper is a relationship between the component demands and the annual probability density function corresponding to every return period. This method accounts for the uncertainties in the environmental loads and structural capacities, and identifies the target mean capacity of each component for maximizing its integrity and meeting the reliability requirement. In addition, because various failure modes in a structural system can lead to different consequences (including damage costs), a method is introduced to compute optimality factors for designated failure modes. By calculating the probability of system failure, this method can be used for risk-based decision-making that considers the failure costs and consequences. The proposed method can also be used on existing structures to identify the riskiest components as part of inspection and improvement planning. The proposed method is discussed and illustrated considering offshore mooring systems. However, the method is general and applicable also to other engineering systems. In the case study of this paper, the method is first used to quantify the reliability of a mooring system, then this design is revised to meet the DNV recommended annual probability of failure and for maximizing system integrity as well as for a designated failure mode in which the anchor chains are the first components to fail in the system.     

含裂纹钢板复合材料修补强度和刚度数值分析

用ANSYS有限元分析软件对复合材料补片修复含边裂纹和中心裂纹钢板的强度和刚度进行了数值分析.引入相对刚度的概念,研究了钻有止裂孔裂纹的长度对损伤钢板相对刚度的影响,分析了损伤钢板刚度复合材料贴片修补效果;引入屈服载荷提高率的概念,分析了损伤钢板强度的修复效果.     

混凝土道路、堆场面层裂缝的产生与防治

从混凝土道路、堆场的各个结构层分析裂缝产生的原因,并针对性地说明预防措施,阐述裂缝维修方法。     

舰艇反鱼雷技术

对目前舰艇反鱼雷技术中的非杀伤、软杀伤和硬杀伤等比较先进的手段进行了阐述,并在此基础上分析研究了舰艇反鱼雷技术的发展趋势。     

利比亚米苏拉塔市萨瓦瓦区5000套住宅项目中心区设计

从确定符合项目实际情况的设计原则入手,通过利比亚米苏拉塔市萨瓦瓦住宅区中心区总体布局和建筑设计两个方面的设计实践,探讨了"传统、现代与文脉"这一当今时代无法回避的文化议题。并且针对具有鲜明文化、宗教和气候特征的建筑设计的特点、方法与风格进行了总结,为今后的实践提供借鉴。     

Community-Based Management for Sustainable Fisheries Resources in Phang-nga Bay,Thailand

Fishing communities, the Government of Thailand Department of Fisheries, local nongovermnental organizations, universities, the Food and Agriculture Organization of the United Nations (FAO), and FAO's Bay of Bengal Program have undertaken a partnership in management of Phang-nga Bay's coastal resources. It is the first project of its kind in Thailand, and although still in the early stages, offers insights that may contribute to our knowledge of how we can improve our management of coastal resources, including the importance of (1) building relationships within the governance process; (2) combining education, enforcement, and economic incentives to achieve compliance; (3) implementing solutions early; and (4) government support of community-based decisions. These insights reinforce trends emerging in other coastal management projects in the Asian region.