船上海气之间湍流通量的观测研究   总被引：3，自引：0，他引：3  

胡敦欣  赵永平  陆蔼庆  陈永利  黄雅天 《海洋与湖沼》1996,27(2):163-168

用６个加速度计组阵系统来监测船体姿态和运动，校正船上观测到的风湍流资料，然后用涡动相关技术计算海气之间动量，热量和水汽通量，结果表明，本观测系统可精确地消除船体运动对风湍流的影响，并获得精确的海气湍流通量。  相似文献   

Mooring Model Experiment and Mooring Line Force Calculation     

XIANG  Yi 《中国海洋工程》2001,(1):25-36

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工程船锚泊移位系统的最优控制策略及拟静力分析   总被引：3，自引：0，他引：3  

冯刚  吴海帆等 《海洋工程》2001,19(4):1-4

锚泊移位系统以定位准确，投资小，节省能源，操纵简便等优点在海上施工工种船中获得广泛的应用。本文分析了工程船锚泊移位系统的受力特点，提出了工程船锚泊移位系统的最优控制策略和锚泊移位系统的拟静力分析方法。并以8锚工程船锚泊移位系统的设计方案为实例进行了计算分析。  相似文献   

西沙群岛附近海域船舶尾迹水体遥感反射率特性的实验测量与分析     

张宇  张永刚  王华 《热带海洋学报》2007,26(2):22-25

利用海上实验现场测量船舶的尾迹气泡群对西沙群岛附近海域一类水体海水光学特征(例如归一化离水辐亮度、遥感反射率)的影响,为通过星载光学传感器遥感获取船舶尾迹信息提供理论依据。实验证明,在可见光和近红外波段,船舶含气泡尾迹不仅在幅度上、也在谱形上改变海水遥感反射率,作为结果,尾迹气泡使得海水变得更绿;同时,随着观测点在尾迹中的位置距目标船的接近,气泡密度不断增大,反射率也随之增强。  相似文献   

Studies on an algorithm to control the roll motion using active fins     

S. Surendran  S.K. Lee  S.Y. Kim 《Ocean Engineering》2007,34(3-4):542-551

The very purpose of attaching fins to the hull is to reduce the roll motions of a ship. Roll minimization is a requisite for various operations in the seas. The presence of fin system provides enhanced state of stabilization especially when the vessel is performing a fast maneuvering amidst rough environmental disturbance. The fins in turn are activated by electro-hydraulic mechanism based on the in-built intelligence as per control theory like proportional–integral–derivative (PID) or fuzzy logic. As per this paper, fin system is activated using PID control algorithm. A frigate-type warship is considered for the demonstration purpose. Nonlinear roll motions are controlled using active fins. Lift characteristics of the fins in hydrodynamic flow were studied using CFD package fluent.Good amount of reduction in roll amplitude is achieved from various simulations in random sea. The approach can be used for any irregular sea conditions.  相似文献   

在AutoCAD平台上应用ActiveX技术进行船体曲面造型     

袁知贵  林焰等 《海洋工程》2001,19(1):79-83

论述了AutoCAD ActiveX Automation,并就应用Active技术进行二次开发AutoCAD的问题，讨论了如何引用对象和使用对象的方法和属性、使用文档对象的事件、用ADO（ActiveX Data Objects)开发基于数据库的应用程序等。通过应用ActiveX技术，在AutoCAD中构造了船体曲面。  相似文献   

Robust path-following of underactuated ships: Theory and experiments on a model ship   总被引：1，自引：0，他引：1  

K.D. Do  J. Pan 《Ocean Engineering》2006,33(10):1354-1372

A method is proposed to design a new global controller that forces an underactuated ship to follow a reference path under disturbances induced by wave, wind and ocean-current. The controller is designed such that the ship moves on the path with an adjustable forward speed and its total velocity is tangential to the path. The ship under consideration is not actuated in the sway axis, and the mass and damping matrices are not assumed to be diagonal. Nonlinear damping terms are also included to cover both low- and high-speed applications. The new result is facilitated by choosing an appropriate origin of the body-fixed frame, designing a suitable filter of sway velocity, several nonlinear coordinate changes, the backstepping technique, and utilizing the ship dynamic structure. Experimental results on a model ship illustrate the effectiveness of the proposed method.  相似文献   

Ship Hull Slamming Analysis with Nonlinear Boundary Element Method     

Lu Chihua He Yousheng Post Doctor 《中国海洋工程》1997,(4)

A boundary element method is developed for calculating the flare ship hull slammingproblem.The nonlinear free surface elevation and the linear element assumption are employed.The meth-od has been verified by comparisons with results for the water entry of wedges with various deadriseangles.Numerical results show that the pressure distribution varies greatly with the ship hull with differentcurvilinear equations,and the slamming features are also different.From the numerical simulation,the au-thors found that the structural damage of the flare hull might be caused by the increasing hydrodynamicpressure over an extensive area on the flare when the upper part of the flare comes into contact with water.  相似文献   

Cost-Benefit Assessment of Inspection and Repair Planning for Ship Structures Considering Corrosion Model Uncertainty     

李典庆唐文勇  张圣坤 《中国海洋工程》2005,19(3):409-420

Owing to high costs and unnecessary inspections necessitated by the traditional inspection planning for ship structures, the risk-based inspection and repair planning should be investigated for the most cost-effective inspection. This paper aims to propose a cost-benefit assessment model of risk-based inspection and repair planning for ship structures subjected to corrosion deterioration. Then, the benefit-cost ratio is taken to be an index for the selection of the optimal inspection and repair strategy. The planning problem is formulated as an optimization problem where the benefit-cost ratio for the expected lifetime is maximized with a constraint on the minimum acceptalbe reliability index. To account for the effect of corrosion model uncertainty on the cost-benefit assessment, two corrosion models, namgly, Paik＇ s model and Guedes Soares＇ model, are adopted for analysis. A numerical example is presented to illustrate the proposed method. Sensitivity studies are also providet. The results indicate that the proposed method of risk-based cost-benefit analysis can effectively integrate the economy with reliability of the inspection and repair planning. A balance can be achieved between the risk cost and total expected inspection and repair costs with the proposed method, which is very. effective in selecting the optimal inspection and repair strategy. It is pointed out that the corrosion model uncertainty and parametric uncertaintg have a significant impact on the cost-benefit assessment of inspection and repair planning.  相似文献   

测量船水声换能器透声板防腐涂料测试     

刘保良  赵先龙  李广建 《海洋测绘》2012,(3):62-64

针对测量船声学换能器透声板表面腐蚀问题,分析了发生原因和防腐措施的技术途径。提出了兼顾防腐、透声和化学兼容等性能的技术路线,对选择的三种涂料进行声学测试,确定采用在防海生物性能、透声性能和材料间结合性能等方面达到适用的技术方法和涂料。  相似文献