Prediction of hydrodynamic forces on a moored ship induced by a passing ship in shallow water using a high-order panel method

A three-dimensional high-order panel method based on non-uniform rational B-spline (NURBS) is developed for predicting the hydrodynamic interaction forces on a moored ship induced by a passing ship in shallow water. An NURBS surface is used to precisely represent the hull geometry. Velocity potential on the hull surface is described by B-spline after the source density distribution on the boundary surface is determined. A collocation approach is applied to the boundary integral equation discretization. Under the assumption of low passing speed, the effect of free surface elevation is neglected in the numerical calculation, and infinite image method is used to deal with the finite water depth effect. The time stepping method is used to solve the velocity potential at each time step. Detailed convergence study with respect to time step, panel size and Green function is undertaken. The present results of hydrodynamic forces are compared with those obtained by slender-body theory to show the validity of the proposed numerical method. Calculations are conducted for different water depths and lateral distances between ships, and the detail results are presented to demonstrate the effects of these factors.     

VD4型真空断路器故障分析

ABB公司生产的VD4型真空断路器在港口中压配电系统中被广泛使用,但在装设“五防”机构时,会出现由于机械连锁失灵而导致断路器无法合闸的现象。     

基于UML的列车自动防护系统测试用例生成方法研究

文章研究基于UML的列车自动防护系统测试用例的生成方法.对基于UML的列车自动防护系统测试技术进行分析,采用UML生成XML测试脚本的3层设计方法,分别从概念层、逻辑层和物理层对列车自动防护系统进行描述,通过转换规则与对应关系,生成XML Schema形式的测试用例.     

汽车交流发电机的匹配设计

交流发电机作为现代汽车电源部分的一个重要部件,其工作性能的好坏对车辆的运行非常重要。本文介绍交流发电机的分类、工作特性及其匹配设计。     

Review of Transportation and Energy Consumption Related Research

With high consumption of energy, especially petroleum resources, transportation industry has received much concern. In view of this, the paper summarizes the domestic and international research achievements on transportation energy consumption, such as external cost determination of energy consumption, influencing factor analysis, statistical indices and data comparison, interactive relation between transportation energy consumption and social economy, relevant planning and policy making, prediction of energy demand of transportation industry. It also analyzes the characteristics and shortcomings of the existing researches. Some key issues concerning the future researches are put forward, namely, the statistical data collection and comparative indices determination, estimation of comparative consumption factors of different transportation modes, exploration of influencing factors and sensitivity analysis, as well as the establishment of relevant basic data platform and theory and method system.     

八七型铁路抢修钢梁在大吨位架桥机上的应用

八七型铁路抢修钢梁是我国自行研制的铁路战备制式器材,具有承载能力大、单件重量轻、使用率高等特点,适合作大吨位架桥机的主体结构。SPJ900／32拼装式架桥机用八七梁作导梁,介绍了该导梁主体结构构造,进行了安全性验算。对抢修钢梁的推广应用有参考价值。     

美国磁浮系统的经济分析及启示

通过介绍美国磁浮系统研究的有关基础数据和方法,包括研究背景、收入与成本的估算方法以及磁浮系统在单线和网络情况下的财务评价结论,对美国磁悬浮系统经济可行性研究进行了详细介绍.结合中国经济和交通运输业背景,认为磁浮建设应分阶段、分地域逐步进行,并应从提高设备国产化程度、提供高质量服务加强项目整体规划和商业运营等方面提高磁浮系统收益,降低成本.     

双层隔振系统结构参数改变对结构振动的影响

本文应用有限元法研究了流-固耦合条件下船舶隔振系统结构振动问题的计算方法,在考虑流-固耦合状态下,详细研究了双层隔振系统主要结构参数改变对系统结构振动响应的影响,如上下层隔振器刚度、中间体与被隔设备的质量比以及基座弹性模量等,同时进行了计算和试验结果对比分析.     

小水线面双体船粘性流数值模拟

利用商业软件FLUENT对一小水线面双体船(SWATH)的粘性绕流进行数值模拟,得到了不同航速下的三维粘性流场和粘性阻力,通过对计算结果的分析、比较,验证了FLUENT用于预报小水线面双体船粘性阻力和伴流分布的有效性和实用性。     

GO—FLOW法在蔬菜物流安全风险分析中的应用

为了辅助区域农产品物流安全风险控制,依据长沙地区的实际调研,分析了跨区域蔬菜物流作业流程,从系统可靠性角度出发,运用GO-FLOW法分别分析和评价了不完全冷链条件下和完全冷链条件下跨区域蔬菜物流安全风险水平,并对运算结果进行了比较分析,结果标明GO-FLOW法可以比较有效地分析与评价跨区域生鲜农产品物流系统安全风险水平,是对现有风险分析与控制方法体系的有效补充和完善.