不同舵速对船舶回转性能影响理论与试验分析

为分析不同舵速对船舶回转性能的影响,采用理论仿真和模型试验相结合的方法,基于流体力学和船舶操纵性基本理论,建立三自由船舶运动模型,对模型进行仿真验证。通过构建自航模试验系统,进行不同舵速下的自航模试验,理论与试验结果表明:不同舵速对战术直径、定常回转直径和横距无明显影响,但对纵距影响较明显。     

转舵速度对舰船回转性能的影响

在忽略操舵引起速降的假设前提下,利用操舵响应方程对不同转舵速度下船舶的回转性能进行理论分析,获得定常回转直径、纵距、横距、战术直径等参数与转舵时间之间的近似关系。进而利用计及速降的非线性操纵性运动方程进行同一舰船不同转舵速度下的回转运动仿真,以及操纵性能和航速相同而船长不同的各船在不同转舵速度下的回转运动仿真。仿真结果与理论分析结果一致,均表明定常回转直径不受转舵速度的影响,纵距、横距、战术直径均随着转舵速度的提高而减小,且转舵速度对船长较短的舰船影响较大。     

舵速对船舶波浪中回转及横摇的影响

基于经典MMG模型和统一理论建立操纵性和横摇四自由度耦合模型,利用耦合模型叠加波浪力的方式来预报船舶波浪中的回转和横摇特性。波浪力采用三维面元法计算,并根据船舶实时速度和遭遇浪向进行二维插值。通过自航模试验进行模型验证,预报了不同操舵速度对船舶回转和横摇的影响。研究表明耦合模型能够有效地仿真船舶的回转及横摇,回转过程中操舵速度越大船舶改变航向和航迹的能力越强,纵距越小,但会给船舶造成较大的横摇。     

船舶操纵性神经计算

利用人工神经网络完成从船舶参数空间到船舶操纵性指标空间的映射。作为输入参量的船舶参数具有一定的自由度,比较符合船舶设计的循序渐进过程。本文采用３层９隐节点ＢＰ网络,９艘次实船资料的拟合结果的精度为０．６１３７（单项平均平方误差）。对船舶操纵性预报进行了初步研究。利用８艘散货船的训练结果,对另１艘同类船舶的回转试验的进距、横距和战术直径进行了预报。     

一种基于k-Means算法的船舶主机工况二次划分方法

为准确划分船舶主机运行工况,提升船舶主机性能监测能力,设计一种基于k-Means算法的船舶主机工况二次划分方法。基于实船运营大数据,分2个阶段开展主机运行工况划分研究,其中：第一阶段,以主机转速和功率为特征参数,初步划分主机运行工况;第二阶段,以海水温度和扫气箱温度为特征参数,对第一阶段划分的工况进行第二次划分。以某大型散货船为例,通过实船试验对该方法的有效性进行验证。试验结果表明,该方法能对复杂的船舶主机运行工况进行有效划分,可为船舶主机性能监测提供状态质量评估和辅助决策,有利于船舶主机健康管理和故障诊断工作的开展。     

基于螺旋桨负荷特性的双桨船操纵性预报

通过对双桨船内、外两桨负荷变化情况及其对舰船回转性和回转速降计算结果影响的分析,提出了采用等功率法分别计算双桨船内、外两桨的转速、进速系数等,进而确定两桨的推力和转艏力矩,从而进行双桨船回转性和回转时速降预报.以某双桨船为例,分别用等转速法、等推力法和等功率法进行回转轨迹、回转时螺旋桨推力、速降和转艏力矩的计算.计算结果表明：采用等功率法与采用等转速法所得到的回转轨迹基本相同,较之等推力法所得到的回转直径的计算结果更接近实船实际情况;采用等功率法所得到的速降介于等转速法和等推力法之间,最为接近实船的实际情况.     

一艘装有回转导管工作船的模型操纵性试验

本文用模型试验方法讨论了装有回转导管工作船的操纵性。对装有回转导管及装有舵的船舶进行了比较试验,同时也对三种不同面积的平衡叶及三种尾呆木切割状态进行了模型试验。通过分折可以得出如下结论:1.装有回转导管的工作船的回转性能比装有舵时为好,倒航时尤为显著。2.变化装于回转导管后面的平衡叶面积,对船舶回转性能无显著影响。3.在相同舵角下,装有回转导管的船舶在稳定回转时的速降大于装有舵时的速降,但在同一无因次角速度下,两者速降一致。4.呆木割除后,船的相对回转直径显著减小,小舵角时更为明显,但航向稳定性随之变差。     

某L型片体小水线面双体船总体性能

简述某L型片体小水线面双体船的特点,从理论计算和模型试验两方面分析目标船的耐波性能。通过理论计算求出船舶的稳性指标参数;通过模型试验给出船舶的阻力系数,分析该船的快速性特点。结合实船测试结果,给出该船的操纵性结果。     

应用“1978 ITTC性能预报方法”进行实船-模型相关分析

本文按照第十五届、十六届国际水池会议的建议,应用“1978ITTC性能预报方法”对22艘单桨海洋船进行了实船——模型的相关分析,全部实船试验数据均符合第十四届水池会议有关规定。分析中对实船数据进行了水温和浅水影响修正。对船模试验数据进行了排水量和转速修正。分析结果给出了可供同类海洋船舶功率与转速预估的C_PC_N数值。分析表明1978 ITTC单桨船舶性能预报方法适用于低速丰满船,适用于高度船。分析还表明第十六届ITTC性能委员会推荐的等功率转速估算法是合理的。     

风载荷作用下的操纵性研究

为研究某水面舰船在一定风载荷作用下的操纵性特点,基于Matlab软件平台和模型试验,构建了静水和考虑风载荷作用下的三自由度MMG操纵性方程,对静水和风载荷作用下的操纵性进行数值预报。通过静水中数值预报结果与试验值的比较,发现仿真值与试验值吻合度较好,从而验证了该方法的可行性。将风载荷作用下的结果与静水中的数值预报结果进行对比分析,结果表明,无因次回转直径、无因次战术直径、速降、无因次横距等回转运动参数都要小于静水中预报值,回转角速度基本与静水预报值一致,无因次纵距要大于静水中的理论预报值;初转周期、超越时间、第一超越角以及第二超越角等Z形运动参数值都要大于静水中预报值,由此可知风载荷对该水面舰船的操纵性相较于静水具有明显的影响,同时该数值预报方法可为工程应用提供借鉴。     

船舶运动姿态测量系统设计与实现

为了获取海上航行船舶及自航模试验中船模的姿态参数,设计一种基于MEMS(微机电系统)技术的波高倾斜一体化传感器的船舶运动姿态测量系统.此系统通过MEMS波高传感器对船舶升沉信息进行采集,利用倾角传感器对船舶的纵摇和横摇姿态信息进行采集,采集到的信息经多路A/D转换后送入单片机进行处理,实时得出船舶运动的升沉、纵摇及横摇变化.经处理后的三组数据由船舶运动姿态测量系统通过RS-485串口送到数据接收处理机存储、分析并实时显示船舶运动的姿态变化曲线,该数据接收处理软件采用VC++编写.经过大量试验及海上测试,该系统性能稳定,测量精度高,具有较大的实用价值.     

A GPS-based system for precise shipping guidance and control

This paper discusses the general concept of an automatic berthing system. The research considered the automatic berthing of a large merchant ship. A global positioning system (GPS)-based system, which provides the necessary information on position, velocity, attitude (roll, pitch, and heading), angular velocity, and time, was the principal sensor used. Field tests were conducted on board a hydrographic sounding ship to assess the quality of information obtained from a GPS-based system. The data were processed using the software with which the algorithms developed in this research were implemented. This paper also discusses various aspects concerning a real-time GPS-based system in relation to an automatic berthing system, such as integration of sensors, mathematical models, port infrastructure, and training of crews. Received: October 22, 1999 / Accepted: June 30, 2000     

STI-VC2100主动力装置实船训练系统实时性探讨

主动力装置实船训练系统是指嵌入在主动力装置监控系统中的机电人员训练模拟系统，它结合了陆上轮机模拟器培训和海上航行训练的优点，具有实施容易，效率高和费用低的特点，能帮助船员迅速获得必要的操作技能和知识。现从嵌入式实船训练系统的组成原理出发，指出了实船训练系统的3个要素——“实时”、“准确”、“柔性”，并从信号流的角度，分析了几个影响训练系统真实性的问题，提出了解决训练系统实时性的方法。     

基于回声状态网络的船舶摇荡连续预报方法研究

回声状态网络（ ESNS）是一种新型递归神经网络,可通过对有限的已知样本进行训练,建立非线性模型来预报未知样本。该算法在解决非线性问题时具有一定优势。无需知道海浪的先验信息和船舶航行姿态的状态方程,仅利用实测的船舶横摇、纵摇历史数据,寻求规律即可进行实测摇荡数据的极短期预报。仿真结果表明,该算法在预报15 s以内可达到较高的预报精度,通过预报窗口的平移,可以进行连续在线预报。     

Full six degrees of freedom coupled dynamic simulation of ship collision and grounding accidents

By taking advantage of the user-defined load subroutine (loadud) and the user common subroutine (usercomm) in LS-DYNA, the authors proposed a new coupled approach for simultaneously calculating structural damage and the planar 3DOF ship motions in ship collisions. The coupled procedure aimed at predicting the detailed structural damage together with reasonable global ship motions. This paper extends the method to consider the full 6DOF ship motions; thus, ship collision as well as grounding accidents can be properly handled. This method is particularly useful for design purposes because the detailed ship hull profile is not needed.A traditional ship maneuvering model is used for the in-plane surge, sway and yaw degrees of freedom with a series of nondimensional coefficients determined from experiments. It is assumed that the out-of-plane degrees of freedom are not coupled with the in-plane ship motions, and there is no coupling among roll, pitch and heave motions. The implementation is verified through free decay tests, and the obtained natural periods show good agreement with theoretical results.Several collision and grounding cases are simulated in which a supply vessel crashes into rigid plates with different orientations. The effects of the roll motion, the heave and pitch motions and the full 6DOF motions are studied. The results are compared with those from a 6DOF decoupled method. Ship motions through the proposed method compare reasonably well with SIMO results. It is found that several consecutive impacts may occur in the simulation of one collision case due to the periodic motions. This is not taken into account in the decoupled method, which makes this method unconservative.     

Improvement of Propeller Hydrodynamic Drag and Efficiency on USCG Cutters Operating in Trailshaft Mode

Large US Coast Guard cutters spend much of their underway time with only one of two propellers operating. The offline propeller is "trailed," often creating a significant amount of hydrodynamic drag. Operators from the fleet do not appear to have any specific guidance on how best to reduce this drag. Using the propeller analysis tools PSF-3 and PSF-10, propeller thrust coefficient values versus advance coefficient values were created for the propellers of the USCG 270' cutters. These values—and the associated drag—vary significantly in magnitude based on the trailed propeller pitch. Based upon sea trial measurements, expected magnitudes of this drag versus pitch setting were predicted. Minimum drag pitch settings were identified for an operational 270' cutter at 8 knots. RPM and pitch settings for maximum hydrodynamic efficiency for the online shaft are sometimes developed during ship acquisition. In the current work, a methodology for conducting such a study is discussed to demonstrate to ship operators the relative ease with which they could perform this analysis on board, if effective power and propeller thrust coefficient values are available. Consideration of prime mover specific fuel consumption rates together with propeller hydrodynamic efficiencies is discussed.     

基于海上作业数据的船用柴油机排放模型验证（英文）

In this study,a model is developed to simulate the dynamics of an internal combustion engine,and it is calibrated and validated against reliable experimental data,making it a tool that can effectively be adopted to conduct emission predictions.In this work,the Ricardo WAVE software is applied to the simulation of a particular marine diesel engine,a four-stroke engine used in the maritime field.Results from the bench tests are used for the calibration of the model.Finally,the calibration of the model and its validation with full-scale data measured at sea are presented.The prediction includes not only the classic engine operating parameters for a comparison with surveys but also an estimate of nitrogen oxide emissions,which are compared with similar results obtained with emission factors.The calibration of the model made it possible to obtain an overlap between the simulation results and real data with an average error of approximately 7% on power,torque,and consumption.The model provides encouraging results,suggesting further applications,such as in the study on transient conditions,coupling of the engine model with the ship model for a complete simulation of the operating conditions,and optimization studies on consumption and emissions.The availability of the emission data during the sea trial and validated simulation results are the strengths and novelties of this work.     

船用激光测距仪稳定平台伺服控制系统设计与实现

实施海上救助时恶劣海况条件通常会造成救助船舶剧烈摇摆,使得测距传感器难以有效地捕捉失事目标,而长时间目标丢失必然造成难以跟踪失事目标或与目标的相对定位失败。因此,该文设计了激光测距仪单自由度稳定平台,通过稳定平台的伺服控制系统补偿来自于船舶纵横摇运动对平台姿态的干扰,并在试验室四自由度转台上完成了稳定平台控制性能的验证试验,试验结果表明:所设计的激光测距仪稳定平台能够很好地补偿船舶运动对激光测距仪姿态的影响,保证了在恶劣环境条件下激光测距仪能够稳定、有效地实时测量失事目标,对于实施有效、安全的海上救助具有重要的工程实际应用价值。     

基于蒙特卡洛法的实船功率性能试验不确定度分析

针对实船功率性能测量与分析涉及因素多,难以通过传统GUM法对修正得到的理想状态功率与航速结果进行不确定度评价的问题,提出基于蒙特卡洛法的实船功率性能不确定度分析方法,分析实船功率性能试验中的主要不确定度源,依据ISO15016数据处理方法建立测量模型,以大连海事大学教学实习船"育鲲"轮为对象分析实船功率性能试验与不确定...     

21000t多用途船的球首设计及尾部节能装置试验

２１０００ｔ多用途船是上海远洋公司在南美洲航线上的定期班船，根据航程、船只数量、航班期的综合分析，要求船舶在主机输出功率７２３９．７５ｋＷ，含有１５％海上功率储备时，航速达到１６．５ｋｎ。为达到船东提出的先进航速指标，进行多次球首设计及尾部前置导管舵球的优化试验。介绍其设计思想及试验结果。