海船船行波对游艇航行安全影响试验

采用不同比尺的物理模型,研究了3万t级海船及游艇在进出港航道中航行产生的船行波特性;利用造波机模拟海船船行波,试验分析了海船船行波对游艇航行安全的影响。研究表明,当航道两侧挡沙堤出水后,对海船航行具有较明显的限制性航道特点;海船航速8节时在游艇航道中产生的最大波高为0.46m,对单游艇航行安全没有影响;当海船和2艘游艇三者同时相遇时,游艇航速宜小于等于10节。     

兴波及航态对螺旋桨激振力预报的影响

针对船舶航行时的船体兴波及航态变化,采用RANS方法、VOF方法及船体六自由度运动方程,建立了考虑船体兴波及航态变化时螺旋桨激振力的计算方法。叠模、考虑船体兴波及考虑航态变化时螺旋桨推力、船底板压力计算结果的对比表明:考虑兴波及航态变化时,由于流速变化,螺旋桨推力平均值减小,船底板压力平均值增大;由于来流不均匀程度的变化,1倍叶频处峰值减小;考虑兴波及航态变化时,计算得到的激振力更加接近真实情况,但由于激振力在频域中较为接近,为节约计算量,计算时可不考虑船体兴波及航态变化。     

Hydro- and aerodynamic analysis for the design of a sailing yacht

The results of the design analysis for a sailing yacht’s hull and sails are reported. The results were used to confirm the design of a 30 ft long sloop, which was planned, designed, and built in Korea for the first time in history. Flows around a sailing yacht above and under the free surface were analyzed separately using both computational and experimental methods. For the underwater flow analysis, turbulent flow simulations with and without free surface wave effects were carried out for the canoe hull with keel/rudder. The computed drag and side forces on the hull model were compared with the measurement data obtained from the towing tank experiments. In order to assess the sail performance, another set of computations was carried out for the flow around a sail system composed of main and jib sails with a mast. The present study demonstrates that, for the design analysis of a sailing yacht, computational fluid dynamics techniques can be utilized with a reasonable level of confidence.     

“润江1”科考船的尾涡抑制研究

通过对“润江1”科考船航行观测资料以及设计布置方案的分析,将过强尾流成因聚焦在船尾涡漩影响,并据此提出了尾涡抑制的相关方案.特殊的舵桨性能试验以及实船海试表明,尾涡抑制可以明显改善实船阻力性能,大幅提高舵桨推进效率和航行速度.     

Sail optimization for upwind sailing: application in a Tornado, the Olympic class catamaran

A study of a boat's motion is carried out in order to analyze the aerodynamic properties of the optimal sail for obtaining the maximum velocity when sailing to windward. The mechanics study shows the optimal C _L and C _D for a given sail and how the shape of the aerodynamic polar of the sail should be. A parametrical analysis of the aerodynamics of a sail is then carried out varying the maximum camber, position of the maximum camber in the chord direction and position of the maximum camber in the mast direction. The parametric analysis is done numerically with a vortex lattice method (VLM) and experimentally in a wind tunnel. The results show that the influence of the relevant parameters studied can be reduced to the variation of two parameters, A and B, defining the polar of the sail, C _D = B + A ² C _L ²; and the influence of parameters A and B on the maximum VMG obtainable are calculated.     

上风向与下风向风机气动力性能数值计算分析（英文）

Although the upwind configuration is more popular in the field of wind energy, the downwind one is a promising type for the offshore wind energy due to its special advantages. Different configurations have different aerodynamic performance and it is important to predict the performance of both downwind and upwind configurations accurately for designing and developing more reliable wind turbines. In this paper, a numerical investigation on the aerodynamic performance of National Renewable Energy Laboratory(NREL) phase VI wind turbine in downwind and upwind configurations is presented. The open source toolbox Open FOAM coupled with arbitrary mesh interface(AMI) method is applied to tackle rotating problems of wind turbines. Two 3D numerical models of NREL phase VI wind turbine with downwind and upwind configurations under four typical working conditions of incoming wind velocities are set up for the study of different unsteady characteristics of the downwind and upwind configurations, respectively. Numerical results of wake vortex structure, time histories of thrust, pressure distribution on the blade and limiting streamlines which can be used to identify points of separation in a 3D flow are presented. It can be concluded that thrust reduction due to blade-tower interaction is small for upwind wind turbines but relatively large for downwind wind turbines and attention should be paid to the vibration at a certain frequency induced by the cyclic reduction for both configurations. The results and conclusions are helpful to analyze the different aerodynamic performance of wind turbines between downwind and upwind configurations, providing useful references for practical design of wind turbine.     

Database of sail shapes versus sail performance and validation of numerical calculations for the upwind condition

A database of full-scale three-dimensional sail shapes is presented with the aerodynamic coefficients for the upwind condition of International Measurement System (IMS) type sails. Three-dimensional shape data are used for the input of numerical calculations and the results are compared with the measured sail performance. The sail shapes and performance were measured using sail dynamometer boat Fujin. This is a boat of 10.3-m length overall in which load cells and CCD cameras were installed to simultaneously measure the sail forces and shapes. At the same time, the sailing conditions of the boat, e.g., boat speed, heel angle, wind speed, and wind angle, were measured. The sail configurations tested were: mainsail with 130% jib, mainsail with 75% jib, and mainsail alone. Sail shapes were measured at several vertical positions for the shape parameters defined by: chord length, maximum draft, maximum draft position, entry angle at the luff, and exit angle at the leech, all of which finally yield three-dimensional coordinates of the sail geometry. The tabulated shape data, along with aerodynamic coefficients, are presented in this article. In addition, numerical flow simulations were performed for the measured sail shapes and the sailing conditions to investigate the capability and limitations of the methods through detailed comparison with the measurements. Two numerical methods were used: a vortex lattice method (VLM) and a Reynolds-averaged Navier–Stokes (RANS)-based computational fluid dynamics method. The sail shape database, in association with the numerical results, provides a good benchmark for the sail performance analysis of the upwind condition of IMS type sails.     

复合材料帆船桅杆强度可靠性分析

针对帆船桅杆失效事件,基于船舶领域可靠度理论,对复合材料帆船桅杆的可靠度进行计算。建立复合材料帆船桅杆的有限元模型,对某一铺层方案进行强度校核。基于可靠性理论,采用JC法和Matlab软件对复合材料帆船桅杆的强度可靠性进行分析,最终得到复合材料桅杆的可靠性指标。该研究能避免传统强度校核采用的确定性方法不能保证结构每个位置在一定概率下都是安全的缺点,对复合材料桅杆的结构可靠性研究具有一定的参考价值。     

Investigation on the vortex structure of propeller wake influenced by loading on the blade

The vortex structure of the wake behind a marine propeller was investigated in terms of loading variation by using particle image velocimetry. One hundred and fifty instantaneous velocity fields were ensemble averaged to study the spatial evolution of the wake and the behavior of the tip vortices in the region ranging from the trailing edge to one propeller diameter downstream. The trailing vorticity was found to be related to the radial velocity jump, and the viscous wake was affected by the boundary layers developed on the blade surfaces. A vortex identification method using the swirling strength was employed to extract the location of the tip vortex. The loading on the blade made a clear difference to the contraction angles. Slipstream contraction occurred in the very near wake region, and unstable oscillation occurred because of reduced interaction between the tip vortex and the wake sheet behind the maximum contraction point for each loading condition. The maximum tangential velocity around the tip vortex center revealed the average radius of its core, which was used for calculating the vortex strength. Additionally, variation of the average radius of tip vortices with the change of blade loading was related to vortex tube stretching in the wake region. The nearly constant vortex strength continued up to one diameter downstream for light loading and design loading conditions.     

An empirical model for estimating berth and sailing times of mega container ships

ABSTRACT

We provide two empirical models for calculating the sailing time and berth time of maritime container liner networks to effectively model the ambiguity associated with sea and port contingency for ex-ante decisions of fleet deployment and route planning. The models are based on recorded AIS data of 110 mega vessels including all the operating container mega vessels with a capacity of 16,000 TEU or more during the summer of 2015. The models are able to estimate the sailing time (with R² of 0.974) and the berth time (with R² of 0.895) without knowledge of any operational-level explanatory variables. The models are validated against the published East Asia–North Europe services. Moreover, the study reveals that vessel operators adopt different berthing and sailing strategies even under the same conditions.     

用升力面理论预报螺旋桨性能和桨叶表面压力分布

本文提出了一个依据升力面理论预报螺旋桨在不同工况下的性能和桨叶表面压力分布的计算方法。该方法计入了桨叶侧斜、纵斜、径向变螺距和径向变伴流等因素的影响。 在附着涡和自由涡的分析中引入模式函数,导出桨叶区内变密度自由涡的涡强分布,从而得到了表达整个涡系的涡强分布公式,并以此计算由整个涡系产生的诱导速度。这就使得有可能用较短的计算时间和较少的计算机存储量以较高的精度求解一个如此复杂的问题。 作者已经提供了一个理论计算程序。一些计算实例与实验结果的比较表明本文所提供的方法是令人满意的。     

基于分数阶PIλDμ的船舶航向控制

船舶在海上航行时受到海风、海浪和海流等环境扰动作用,这造成在不同航速下船舶动力学模型的参数不确定性,本文对船舶本体运动和风浪流干扰进行建模,提出一种基于分数阶PIλDμ的抑制风浪干扰的的航向控制算法,并与传统 PID算法进行对比,针对某型船舶动力学模型在6级海风和5级海浪海况下进行对比数字仿真。仿真结果表明,该算法在不同航速下具有较好的控制品质和鲁棒性,对风浪干扰具有良好的适应性,可应用于船舶的航向控制,易于工程实现。     

Optimum routing of a sailing wind farm

To acquire the wind energy of the oceans, a sailing wind farm has been proposed. The wind farm considered is composed of a semisubmersible floating structure, 11 windmills, four sails, six thrusters, and storage for hydrogen. To maximize the acquired energy, an effective algorithm to search for optimum routes was developed. The algorithm is based on the fact that beam winds yield a maximum of acquired energy. This feature reduces the computation time, and, consequently, efficient route optimization becomes possible in a reasonable time. After setting an operational area for the wind farm, navigation simulations for a 1-year period were carried out. A numerical weather forecast was used as well as the responses of the floating structure, such as the speed of the structure, the output power of the windmills, and the time of course changes. In the simulation, the wind farm evades rough seas to avoid structural damage, and an optimum route is searched for. The capacity factor of the system was used to evaluate the efficiency of the optimized routes. From the simulations, the maximum capacity factor achieved was 42.6%. The dependency of the capacity factor on the initial position of the wind farm was also examined. It was shown that offshore from Sanriku in northeastern Japan is an area suited to the operation of the wind farm. The effect of the initial position on consecutive periods of operation is discussed.     

用准定常升力线理论预报螺旋桨在非均匀流场中的性能

本文应用准定常升力线理论预报船用螺旋桨的性能,建立了适合中型计算机的程序。通过四个桨模的敞水试验和性能计算结果比较表明,对于计算螺旋桨的推力与转矩系数,只要应用升力线理论加上简单的粘性经验修正及升力面影响修正,不必作边界层计算即可得到比较满意的结果。伴流场中单个叶片推力与转矩脉动计算表明,用升力线作计算时,伴流产生的水流弯曲对推力、转矩脉动有较明显的影响,对推力偏心度则影响不大,计算所得的推力、转矩脉动可供计算主机扭振及轴系振动的外力作参考。     

环厦门湾水域游艇活动安全现状及航路规划探讨

分析环厦门湾游艇活动现状,结合环厦门湾水域游艇泊位建设规划,提出环厦门湾游艇活动水域和游艇航路规划建议,供相关部门制订游艇航路规划和管理政策参考。     

新型半潜式风力发电安装平台概念设计与整体强度分析

在确定总布置方案和主尺度的基础上,针对新型半潜式风车安装平台进行强度验证和结构优化。采用Sesam软件建立平台结构整体模型和水动力模型,基于设计波法对平台自存、操作、航行工况下的整体强度、节点、杆件和局部进行规范校核。充分考虑运输安装一体化的作业形式,给出风机整体运输和吊装方案,完成平台的基础设计工作。研究表明:新型半潜式平台的整体应力分布、杆件和节点利用率、关键区域局部强度基本满足规范要求;一体化运输安装方式充分考虑了经济性和安全性要求,提高了海上风电安装的作业效率。     

一种新型舢板帆船训练远程监控系统

针对我海军院校各级指挥决策机关对于海上舢板帆船训练的信息掌握不够全面,特别是在大风浪和能见度不良情况下缺乏有效的指挥手段和安全措施。依托船舶自动识别系统(AIS)和北斗卫星通信系统的短报文功能,构建一种基于"AIS+北斗"训练模式的新型舢板帆船训练远程监控系统,保障各级指挥决策机关对于所属舢板、帆船的航行训练数据进行远程监控,为提高海上舢板帆船训练指挥的自动化水平提供技术支持。     

吊舱式CRP推进系统理论设计研究

采用螺旋桨旋涡理论和低阶速度势面元法对吊舱式CRP进行适伴流设计。在吊舱给定的前提下对前后桨进行升力线设计和升力面修正,吊舱与前后桨之间的相互影响通过诱导速度来考虑,且诱导速度作为伴流的一部分,并采用面元法进行非定常水动力性能预报。通过实例设计分析可知:在设计进速条件下,采用该方法设计的吊舱式CRP系统与设计的单桨相比,其效率可提高8.533%,设计吊舱式CRP尾流周向诱导速度明显小于单桨时的速度。     

竞赛帆船龙骨盒结构优化设计

龙骨盒是竞赛帆船特有的结构,其功能是维持压载龙骨竖直升降,因其为帆船主要受力构件之一,实际使用中易损坏,提高龙骨盒强度是企业和艇主亟须解决的问题。通过水动力分析获得龙骨盒结构响应,运用多级优化对龙骨盒帽型材和桅杆作用区域进行形状、尺寸优化和铺层顺序优化。优化结果显示,基于响应面法和遗传算法的多级优化降低75.92%的龙骨盒整体应变能和提高29.40%的铺层强度比,该方法对提升龙骨盒强度和承载能力具有实用和借鉴意义。     

由推进器尾流计算确定动力艇合理牵引间距研究

针对动力艇尾流作用于被牵引船只,造成水阻力增加而使牵引效率下降的问题,提出通过数值模拟方法计算动力艇尾流场,进而确定合理的牵引间距的方法.文章应用理想推进器理论,给出了确定推进器尾流出口横截面面积和喷水流速的方法.在此基础上,通过数值模拟计算推进器尾流场的影响,并通过分析估计出给定牵引航速下的合理牵引间距.该方法可以结合动力艇的拖钩拉力与航速曲线,确定组合体可能达到的最大设计航速.