Application Progress of Computational Fluid Dynamic Techniques for Complex Viscous Flows in Ship and Ocean Engineering

Complex flow around floating structures is a highly nonlinear problem,and it is a typical feature in ship and ocean engineering.Traditional experimental methods and potential flow theory have limitations in predicting complex viscous flows.With the improvement of high-performance computing and the development of numerical techniques,computational fluid dynamics(CFD)has become increasingly powerful in predicting the complex viscous flow around floating structures.This paper reviews the recent progress in CFD techniques for numerical solutions of typical complex viscous flows in ship and ocean engineering.Applications to free-surface flows,breaking bow waves of high-speed ship,ship hull-propeller-rudder interaction,vortexinduced vibration of risers,vortex-induced motions of deep-draft platforms,and floating offshore wind turbines are discussed.Typical techniques,including volume of fluid for sharp interface,dynamic overset grid,detached eddy simulation,and fluid-structure coupling,are reviewed along with their applications.Some novel techniques,such as high-efficiency Cartesian grid method and GPU acceleration technique,are discussed in the last part as the future perspective for further enhancement of accuracy and efficiency for CFD simulations of complex flow in ship and ocean engineering.

Knowledge-based engineering approach for the support of ship structure design

The paper presents a knowledge-based engineering （KBE） approach for ship node components design. In the ship design process, many design tasks need design experiences to support. Howev- er, a ship design process is a complicated process with many simultaneously repetitive and time-con- suming activities. In this research, the method combines KBE with Tribon system＇s built-in devel- opment language tools of Vitesse, captures and applies design knowledge for achieving standard com- ponents intelligent design modeling. A case study and industry implementation illustrate the feasibili- ty of the proposed methodology. The KBE technique can provide not only proper references, sug- gests and supports but also knowledge integrated in the ship structure design. Especially, these rules related to the design can avoid lots of design mistakes. During the ship design stage, getting more precise and better designs will not only reduce the time of rework and wasting resources but also shorten the construction time_ imnrov~ clilnl;hz ~nA nrnf;t

The Origin of Chinese Modem Engineering Education： Fuzhou Shipping School＇s Engineering Education at Late Qing Dynasty

Engineering education is an important issue in engineering practice, and engineering practice and characteristics can be seen through examining the history of early Chinese engineering education. During the period ranging from the 1860s to the middle of the 1890s, the westernization group set up a series of modern industrial and mining enterprises for military and civil use, making the implementation of modern engineering education become possible and necessary. Thanks to their efforts, many schools and old-style private schools for teaching knowledge about western science and technology and training senior engineering managements and talents were gradually founded in China. These modern education organizations are the source and beginning of Chinese engineering education, which is also the origin of modernization of Chinese engineering education. This article takes Fuzhou Shipping School for case studies, using a cultural anthropology approach to examine the overall status, basic characteristics, and impact evaluation of engineering education during the Westernization Movement in China. It reiterates the idea of that ＂engineering education should be returned to engineering practice,＂ and tries to explain the framework of the development of engineering education in China. Through conducting research, we find that the development of engineering education in modem China generally has the basic resources for realization of internationalization through ＂westernization＂ and localization through traditional culture and education and the general characteristics of diversification of social influence. During the development process, it has accumulated valuable experience for timely reform and gradual improvement of modernization： attaching importance to culture and cultivating qualified technical personnel; strictly requiring and building high-level schools and specialties; learning the advanced knowledge and bravely utilizing foreign educational resources; setting pragmatic and highly pertinent disciplines and specialties. It also left the society with thought-provoking lessons, namely, the lagging industrial production and social instability made the development severely restricted and obstructed; the unreasonable development layout resulted in the intensified imbalanced development in different regions; the bureaucracy nature imposed serious impact on efficiency and effectiveness of education; the negligence of innovation made the great-leap-forward development failed, etc.

Review on the Progress and Issues in Liquid Tank Sloshing of Ships

With the development of large liquid cargo ships,liquid tank sloshing has gradually become a hot research topic in the area of shipping and ocean Engineering.Liquid tank sloshing,characterized by strong nonlinearity and randomness,not only affects the stability of the ship but also generates a huge impact force on the wall of the tank.To further investigate liquid tank sloshing,a comprehensive review is given on the research process of the most focused subjects of liquid sloshing.Summarizing the existing research will help to identify issues in the current field and provide useful references.The methods for investigating sloshing,the research progress and the situations worldwide are discussed.The advantages and defects of experiments and numerical simulations are also explored.The problems which need to be explored in the future are subsequently proposed.

Study on Anti-ship Missile Saturation Attack Model

Based on the analysis for the interception process of ship-to-air missile system to the anti-ship missile stream, the antagonism of ship-to-air missile and anti-ship missile stream was modeled by Monte Carlo method. This model containing the probability of acquiring anti-ship missile, threat estimation, firepower distribution, interception, effectiveness evaluation and firepower turning, can dynamically simulate the antagonism process of anti-ship missile attack stream and anti-air missile weapon system. The anti-ship missile's saturation attack stream for different ship-to-air missile systems can be calculated quantitatively. The simulated results reveal the relations among the anti-ship missile saturation attack and the attack intensity of anti-ship missile, interception mode and the main parameters of anti-air missile weapon system. It provides a theoretical basis for the effective operation of anti-ship missile.

Inspiration of the functional localization of a US naval hospital ship on a Chinese hospital ship

Through the experience of being stationed on the USS Mercy hospital ship(T-AH19) and a preliminary comprehension of the personnel and material arrangements,processing and functional formats,and the multi-platform contributions of US Navy hospital ships,we briefly introduce the characteristics of US hospital ships regarding medical support,emergency rescue exercises,communications and training,international humanitarian aid,etc.We discuss the function and responsibility of Chinese hospital ships,focusing on the investigation of the construction mode and positioning in the navy.

Fault Tree Analysis of Fire and Explosion Accidents for Dual Fuel （Diesel/Natural Gas） Ship Engine Rooms

In recent years, China's increased interest in environmental protection has led to a promotion of energy-efficient dual fuel(diesel/natural gas) ships in Chinese inland rivers. A natural gas as ship fuel may pose dangers of fire and explosion if a gas leak occurs. If explosions or fires occur in the engine rooms of a ship, heavy damage and losses will be incurred. In this paper, a fault tree model is presented that considers both fires and explosions in a dual fuel ship; in this model, dual fuel engine rooms are the top events. All the basic events along with the minimum cut sets are obtained through the analysis.The primary factors that affect accidents involving fires and explosions are determined by calculating the degree of structure importance of the basic events.According to these results, corresponding measures are proposed to ensure and improve the safety and reliability of Chinese inland dual fuel ships.

A Case Study of a Solid Oxide Fuel Cell Plant on Board a Cruise Ship

The work is a case study of a cruise ship supplied by liquefied natural gas(LNG)and equipped with a solid oxide fuel cell(SOFC).It is supposed that a 20 MW SOFC plant is installed on-board to supply hotel loads and assisting three dual-fuel(DF)diesel/LNG generator sets.LNG consumption and emissions are estimated both for the SOFC plant and DF generator sets.It results that the use of LNG-SOFC plant in comparison to DF generator sets allows to limit significantly the SO_(x),CO,NO_(x),PM emissions and to reduce the emission of CO_(2)by about 11%.A prediction of the weight and volume of the SOFC plant is conducted and a preliminary modification of the general arrangement of the cruise ship is suggested,according to the latest international rules.It results that the SOFC plant is heavier and occupies more volume on board than a DF gen-set;nevertheless,these features do not affect the floating and the stability of the cruise ship.

Study on the Digital Manufacturing System of Ship Model Surface

Because a ship model surface (SMS) is a large double-curved 3-D surface,the machining efficiency of the cur- rent handcraft manufacturing method are very low,and the precision is difficult to control also.In order to greatly improve the machining efficiency and precision of SMS,based on the CAD/CAM/CNC technology,this paper proposed a model of SMS digi- tal manufacturing system,which is composed of five functional modules (preprocess module,CAD module,CAM module,post- process module and CNC module),and a twin-skeg SMS as an example,the key technologies & design principle of the nodtules were investigated also Based on the above research works,the first set of 4-axis SMS Digital Manufacturing System in China has been successfully developed,which can reduce the machining time of the twin-skeg SMS from 30 working days needed for the cur- rent handcrafting manufacturing method to 8 hours now,and which can control more effectively the precision of SMS also.

基于SHIPFLOW内河船阻力预报研究

基于SHIPFLOW软件模拟内河船舶周围流场,考虑流体黏性及自由表面影响,预报船舶阻力,选择3种船体网格(CC,MM,MF)进行船体表面网格划分,采用势流理论与黏流理论的分区分步计算方法(ZONAL法),将数值计算的船舶总阻力与根据艾亚法经验公式估算出的总阻力对比,计算结果表明:网格划分形式MM的计算结果与经验法最为接近,同时验证了SHIPFLOW软件求解技术的可靠性并提高了换算效率,最后选择MM网格化分形式,对该船进行阻力预报。

Penetration Capability Comparison of the Same Anti-ship Missiles Between Millimeter and Centimeter Wave Seekers

This paper compares the penetration capabilities of the same type anti-ship missiles with millimeter wave(MMW)seeker and centimeter wave seeker,and constructs mathematical models of penetration probability and saturation attack number for all anti-ship missiles used in the countermeasure system,according to the rule which makes the ship-borne air defence system oppase as far as possible and equally,and combining the actual combat situation.It can be seen,from analysis of the countermeasure process between anti-ship missile and surface naval ship,that for the same type of anti-ship missile with different seekers,the main influence on the penetration capability is from electronic jamming system.Based on the built model,the penetration capabilities of the same type anti-ship missiles with MMW and centimeter wave seekers are simulated.The simulated results show that the penetration capability of MMW seeker is slightly better than that of the centimeter wave seeker and its saturation attack number is also influenced by the discovering probability greatly.Finally,some suggestions to get superior penetration effect are given for a commander to choose seeker type suitably.

Numerical techniques for coupling hydrodynamic problems in ship and ocean engineering

Most hydrodynamic problems in ship and ocean engineering are complex and highly coupled.Under the trend of intelligent and digital design for ships and ocean engineering structures,comprehensive performance evaluation and optimization are of vital importance during design.In this process,various coupling effects need to be accurately predicted.With the significant progress of computational fluid dynamics(CFD),many advanced numerical models were proposed to simulate the complex coupling hydrodynamic problems in ship and ocean engineering field.In this paper,five key coupling hydrodynamic problems are introduced,which are hull-propeller-rudder coupling,wave-floating structure coupling,aerodynamic-hydrodynamic coupling,fluid structure coupling and fluid-noise coupling,respectively.The paper focuses on the numerical simulation techniques corresponding to each coupling problem,including the theories and the applications.Future directions and conclusions are provided finally.

An Analysis on Application and Trend of Low-Alloy Steel in Shipbuilding and Offshore Engineering Industry

Since 2003,China shipbuilding industry has stepped into the orbit of fast growth.In this paper,a brief analysis has been made on application of low-alloy steel in the shipbuilding and offshore engineering industry,and the further requirements on the marine steel plates elaborated in combination with the future development trend in this industry.Meanwhile,a reference approach is proposed for potential cooperation between the shipbuilding industry and steel industry.

基于性能的通航桥梁抗船撞评估方法及应用研究

为合理有效地开展通航桥梁抗船撞性能评估,提出基于性能的桥梁抗船撞标准化评估方法。基于现行《公路桥梁抗撞设计规范》(JTG/T 3360-02-2020),从抗撞性能等级确定、设防代表船型确定、船撞力计算、船撞效应计算以及抗撞性能验算等方面,采用结构性能目标作为评估准则,建立桥梁抗撞性能评估各环节流程的标准化评估方法。以江苏扬中三桥为应用实例,运用该方法进行该桥20号墩抗撞性能评估,结果表明:20号墩桩基顺桥向抗弯性能不满足JX1级要求,其余验算结果满足要求,桥墩抗撞性能综合评估结果为不满足要求。参照评估结果该桥加装了浮动式防撞设施。桥梁抗撞性能评估标准化,可准确高效实现桥梁抗撞性能等级确定、船撞效应计算、抗撞性能验算等预期的评估功能要求。

基于速度特征的内河LNG船舶三维动态安全区建模方法

为提高LNG船舶安全区设置的科学性,保障内河水域LNG船舶的通航安全,提出了一种基于速度特征的内河LNG船舶三维动态安全区建模方法。基于LNG船舶航行方向和速度变化的特点,将传统速度的线性分布模型改进为随机分布模型;利用区域分解法,将复杂的三维几何区域分解成若干个子区域,建立相应的边界方程;基于船舶间极限通过设定约束条件,根据其几何形状,运用停船视距理论、船舶漂移计算方法和富余水深计算方法对安全区内部结构不同方位的安全距离进行数值求解。针对某内河LNG船舶,通过设置不同速度条件进行仿真验证。研究结果表明:该模型能较真实反映船舶安全区在速度影响下的差异变化,为内河LNG船舶航路规划起到参考作用。

超声空化在船舶与海洋工程中的应用

Biofouling on ships and offshore structures has always been a difficult problem to solve,which not only jeopardizes the structural strength but also brings great economic losses.Ultrasonic cavitation is expected to solve this problem due to its characteristics of no damage to structures and no pollution.Starting from the phenomenon and mechanism of ultrasonic cleaning,this paper introduces the application of ultrasonic cavitation in ship,pipeline and oil cleaning as well as ballast water treatment.By reviewing the existing studies,limitations such as insufficient ultrasonic parameter studies,lack of uniform cleanliness standards,and insufficient cavitation studies are summarized to provide traceable research ideas for improving ultrasonic cavitation technology and to guide the expansion and improvement of its applications.

双向门控循环单元在船舶轨迹预测中的应用

针对传统循环神经网络提取船舶轨迹序列特征能力不足,导致预测结果与实际轨迹之间的误差较大,影响船舶调度与航行安全的问题,将双向门控循环单元(Bidirectional Gated Recurrent Unit, Bi-GRU)神经网络应用到船舶轨迹预测中。利用Bi-GRU神经网络模型具有的前瞻特性以及大量船舶自动识别系统(Automatic Identification System, AIS)数据,提出基于Bi-GRU的船舶轨迹预测模型。结果表明,Bi-GRU的预测精度较门控循环单元(Gated Recurrent Unit, GRU)有明显提升,均方误差降低13.0%,均方根误差降低6.5%,平均绝对误差降低16.5%。研究成果可为提高船舶交通服务系统安全管理水平、判断船舶交通风险程度及智能船舶碰撞预警提供理论支撑。

将多元技术引入船海专业核心实验课程的改革与实践

基于船海工业近年来发展的大背景,面向社会对高校培养船海专业人才的需求,以船海专业培养过程中的核心实验课程为目标开展研究,并在哈尔滨工程大学开展将多元技术引入船海专业核心实验课程的改革实践。首先,通过虚拟现实技术构建船海专业核心实验课内容,将大型实验课程的设备、流程、效果全部虚拟化,即使不在实验场地也可以身临其境地体验实验过程,极大地降低了开展船海专业实验课程的门槛;其次,将科研用途的自研仪器用于教学实验过程中,不仅在实验教学中增加了先进技术,而且支持开展更多拓展实验,鼓励学生自主设计实验内容与方案;最后,通过实验建立多元技术引入的船海专业核心实验课程教学模式,增强船海专业核心实验课程的自主性与适用性,满足了专业核心实验课程改革需求,为船海专业核心实验课程改革提供指南。

基于行船视距的船舶会遇安全距离研究

近年来船舶交通流量大幅增加,船舶会遇愈加频繁。为降低船舶会遇避让时的碰撞危险,在行车视距基础上,提出行船视距的概念,并引入航速、避让航向角等参数,构建基于行船视距的船舶领域模型,船舶采取避让操作时,可利用该模型判断应与他船保持的安全距离和最佳航速及避让航向角。从仿真结果发现:船舶追越时应尽量与他船保持3.5倍船长以上距离,并在船尾与他船达到2倍船长以上距离时回到原航向;对遇时应尽量与他船保持7倍船长以上距离采取避让,如果航道宽裕,避让时应尽量与他船横距保持1.8倍船长以上,如果航道较窄,也应尽量保证船舶在可航水域内进行大角度避让,并与他船横距保持0.72倍船长以上。研究结果可为实际船舶避让提供指导建议。

船舶推进装置工程应用技术分析

船舶推进技术是船舶工程应用技术中传统的配套方向,追上和缩小其与国外技术及产品的差距是工程应用技术攻关的主要目标。从目前各类型船舶对推进装置及相关技术的需求焦点出发,回顾和分析当前国内船舶推进技术的发展现状、已经形成的基本能力和技术热点方向。研究表明,通过多年的持续科研投入和产品攻关,我国船舶推进技术在工程应用方面形成了系统性的技术体系,为各型船舶推进装置的配套能力提升建立了技术保障,解决了工程应用的大量技术性问题。该研究可为船舶推进装置工程应用技术的发展提供参考。