喷水推进船操纵性水动力导数影响的试验研究

采用数学模型进行船舶操纵性模拟是常用的方法，但喷水推进船航速高、回转时横倾大，还会出现侧滑现象，有必要开展操纵性水动力影响的研究。论文采用大振幅平面运动机构开展了高速单体喷水推进船的斜航、纯横荡和纯摇首运动的模型试验，在不同航速下对带有喷水推进的船体和裸船体进行水动力测试，分析了与上述运动相关的水动力导数。试验表明，高航速引起的船舶升沉和纵倾等运动姿态较大的变化以及喷水推进作用下船体产生的“虚尾”，使操纵性水动力导数受到很大影响。还发现该船在两个试验航速下都不具有航向稳定性，在总体设计时需要考虑初始尾倾，以消除喷水推进产生的不利影响，必要时需增加呆木或稳定鳍，用于改善航向稳定性。     

船水耦合体的重心位置对船舶操纵影响的体会和探讨

引入船水耦合体概念,如果作用于船舶的力的作用线不经过船水耦合体重心,将产生转船力矩,会对船舶的运动状态产生改变,从而影响船舶操纵。     

螺旋桨斜流效应横向力对船舶操纵影响探析

河船顺、逆流航行于急流滩河段时，常发生“打张”、“打抢”现象，形成紧迫危险局面。甚至发生水上交通事故，这些现象除与局部水流作用于船体局部而产生船体水动力转船力矩使船偏转外，也与螺旋桨斜流效应横向力有关，所以有必要了解此力产生的原理及其对船舶操纵性能的影响，以便正确操纵船舶，避免事故的发生。关键词：斜流；螺旋桨斜流；螺旋桨斜流效应横向力；打张；打抢     

转舵速度对船舶操纵性影响研究

采用MMG分离式水动力模型作为船舶操纵运动数学模型，编写MATLAB程序进行操纵性仿真预报，结合一艘双桨双舵船舶在设计航速下的定常回转运动进行了数值模拟，分析了船在不同转舵速度的回转运动轨迹和相应参数，进而得出转舵速度对船舶操纵性的影响规律。     

析大风浪中船舶走锚后措施

船舶在大风浪中锚泊,当走锚时,其应急操纵是决定船舶安全与否的关键。文中从走锚判断、走锚后错施以及起锚重抛等几个方面分析了船舶操纵的注意事项。特别是起锚后船舶首向的控制以及利用风力转船力矩与舵力转船力矩估算分析了锚离地时船舶可控对应的最大风舷角。以及在起锚过程中控制风舷角的方法。     

浅水域中船舶的操纵运动仿真研究

研究船舶在浅水中的操纵与控制是船舶航行安全的一项重要课题。根据势流理论,以某型船舶为仿真实体,进行仿真建模,通过对船体进行网格划分,基于不同船体网格模型进行浅水域的操纵性计算。研究结果反映出该型船舶在浅水域的操纵特性,为该型船舶在浅水域的操纵提供科学依据,同时对其它船型的操纵性研究具有一定的借鉴意义。     

浅析大风浪中船舶走锚后的措施

文章从走锚判断、走锚后措施以及起锚重抛等几个方面分析了船舶操纵的注意事项。特别是起锚后船舶艏向的控制以及利用风力转船力矩与舵力转船力矩估算,分析了锚离底时船舶可控对应的最大风舷角,以及控制风舷角的方法。     

喷水推进船舶航向稳定性分析

喷水推进是一种船舶推进方式,喷水推进器依靠进流与出流的动量差产生推力,会对船体周围的流动产生显著影响。基于裸船体计算得到的操纵性水动力系数与喷水推进器工作状态下得到的预报之间存在差异,这将影响船舶操纵性的预报。研究项目利用平面运动机构(PMM),分别开展带喷水推进装置的船舶操纵性水动力系数模型试验和相同工况下的裸船体试验,对比各项操纵性水动力系数的变化情况,总结出喷水推进装置对船舶航行稳定性的影响,找到关键的影响因素,为深入探究喷水推进器进出流动对船舶操纵性能的影响打好基础。     

操舵模拟系统建模

分析了风和水流对船舶操纵性能的影响,研究船舶对操舵的动态响应．建立了在风和流共同作用下船舶操纵系统的动力学模型,用于模拟船舶在操舵后的运行状况。同时通过回转性实验对该模型进行了验证。     

基于最小舵系能耗的操舵策略计算方法

对舵系能耗的构成进行计算分析，结合船舶操纵运动数学模型（MMG）建立舵系能耗计算方法，针对具体算例求解以最小舵系能耗为目标的最优操舵策略，讨论相关变量条件对操舵策略及舵系能耗的影响。结果表明：该计算方法具有可行性；对于算例船舶，以10°舵角操舵是使艏向角改变60°的最优操舵策略；不同的舵压力中心位置、舵阻力特性和初始航速条件不会改变算例船舶给定目标任务下的最优操舵策略。研究结果可为船上智能驾驶系统或驾驶人员做出操舵决策提供有效的算法支撑。     

Prediction of ship steering capabilities with a fully nonlinear ship motion model. Part 1: Maneuvering in calm water

This paper introduces a new method for the prediction of ship maneuvering capabilities. The new method is added to a nonlinear six-degrees-of-freedom ship motion model named the digital, self-consistent ship experimental laboratory (DiSSEL). Based on the first principles of physics, when the ship is steered, the additional surge and sway forces and the yaw moment from the deflected rudder are computed. The rudder forces and moments are computed using rudder parameters such as the rudder area and the local flow velocity at the rudder, which includes contributions from the ship velocity and the propeller slipstream. The rudder forces and moments are added to the forces and moments on the hull, which are used to predict the motion of the ship in DiSSEL. The resulting motions of the ship influence the inflow into the rudder and thereby influence the force and moment on the rudder at each time step. The roll moment and resulting heel angle on the ship as it maneuvers are also predicted. Calm water turning circle predictions are presented and correlated with model test data for NSWCCD model 5514, a pre-contract DDG-51 hull form. Good correlations are shown for both the turning circle track and the heel angle of the model during the turn. The prediction for a ship maneuvering in incident waves will be presented in Part 2. DiSSEL can be applied for any arbitrary hull geometry. No empirical parameterization is used, except for the influence of the propeller slipstream on the rudder, which is included using a flow acceleration factor.     

Study on the maneuverability of a large vessel installed with a mariner type Super VecTwin rudder

The suitability of the Mariner type Super VecTwin rudder (hereinafter, the MSV rudder) for a large vessel is assessed in this article. Several experiments in a maneuvering pond were carried out and their results analyzed and summarized. Free-running tests such as turning, zigzag, and stopping tests were carried out with a 4-m free-running model of a very large crude carrier (VLCC) ship with the MSV rudder and the Mariner rudder. The results were compared to validate the maneuverability of a VLCC-sized a ship installed with the MSV rudder. A mathematical model of an MSV rudder is proposed for maneuvering simulation of a large vessel. To develop a maneuvering simulation for the model ship that was used in the free-running tests, hydrodynamic coefficients were estimated based on Kijima's regression formula. The coefficients of interaction between the hull and rudder (t_R, a_H, x_H) were obtained from a self-propulsion test in a towing tank. The complicated flow around the rudders is simplified to model the flow speed around the rudders. This simplified flow speed is utilized to compare the time histories of the free-running tests with the simulations. The mathematical model of the MSV rudder was further improved using the results of this comparison.     

基于减摇鳍辅助回转的船舶操纵性能研究

基于MMG分离式建模思想,考虑作用在船体、螺旋桨、舵、鳍的水动力作用,建立双桨双舵船舶四自由度非线性数学运动模型,对某船模在静水中的回转性能进行仿真分析,将单独舵控制的仿真结果与船模试验结果进行了验证和分析,并对比了单独舵控制和舵、鳍联合控制下的回转性能,结果表明鳍参与控制回转时能明显缓解回转过程中的横倾。     

双桨客货轮自航船模操纵性试验研究

本文通过一组典型双桨船型,即常规船型、双尾鳍型及双尾型船的自航船模操纵性试验,探索了双桨船的操纵特点,分析研究了螺旋桨旋向及船型对操纵性的影响规律。研究表明:内旋桨使回转性及错车性能略有下降,但错车仍有正常转向,车舵并用能得到理想的效果。内旋使倒航性能大为改善,使倒航可操。单机倒航时出现有规律的反常转向,可利用作为倒航的操纵手段。双尾鳍船的回转性能优于另两种船型,倒航性能及车舵并用的转首性能亦优于常规型船,是具有良好操纵性的一种船型。双尾鳍船型配以内旋桨方案有广阔的应用前景。     

基于细长体理论的小水线面双体船操纵性预报

小水线面双体船(SWATH)由于具有良好的船舶快速性、耐波性、稳性和效率高等特点,已经成为新船型的代表。根据小水线面双体船的船型结构特点,在操纵运动数学模型的基础上,充分考虑小水线面船的结构特点和双体、双桨、双舵之间水动力的相互影响,采用细长体理论计算了附加质量、附加惯性矩和线性水动力导数,编制了双体船操纵运动预报程序,并结合实例对SWATH的操纵性能进行了预报。     

A study on flow field around full ship forms in maneuvering motion

To estimate the maneuvering ability of a ship, an accurate estimation of the hydrodynamic forces and moment acting on the ship's hull is indispensable. For the purpose of developing a numerical method of computing the viscous flow field around a hull and evaluating its validity, the hydrodynamic pressure on the hull and the velocity field were measured. Two full ship models with different hull forms in the aft part were used for the experiment. From the results of pressure measurements, the distribution of hydrodynamic lateral forces was obtained. The simulation method is a numerical solution of the Navier-Stokes equation based on a finitevolume method and applied to the maneuvering motion. The measured and computed results agree qualitatively well, and the method is a valuable tool for estimating the maneuvering ability of a ship. The typical characteristics of the flow field in the steady turning condition are revealed by the numerical simulation, and the mechanism of the relations between hull form, flow field, and hydrodynamic forces are clarified.Translation and combination of articles that appeared in the Journal of the Society of Naval Architects of Japan, vols. 176, 177, 179 (1994–1996): The original article won the SNAJ prize, which is awarded annually to the best papers selected from the SNAJ Journal, JMST, or other quality journals in the field of naval architecture and ocean engineering.This work was conducted as part of the joint SR221 project supported by JSRA (Shipbuilding Research Association of Japan). The authors express their sincere gratitude to the persons concerned, and especially to M. Kanai, S. Eguchi, S. Usami, K. Tatsumi, and T. Kawamura.     

Computational fluid dynamics (CFD) prediction of bank effects including verification and validation

Restricted waters impose significant effects on ship navigation. In particular, with the presence of a side bank in the vicinity of the hull, the flow is greatly complicated. Additional hydrodynamic forces and moments act on the hull, thus changing the ship's maneuverability. In this paper, computational fluid dynamics methods are utilized for investigating the bank effects on a tanker hull. The tanker moves straight ahead at a low speed in two canals, characterized by surface piercing and sloping banks. For varying water depth and ship-to-bank distance, the sinkage and trim, as well as the viscous hydrodynamic forces on the hull, are predicted by a steady state Reynolds averaged Navier–Stokes solver with the double model approximation to simulate the flat free surface. A potential flow method is also applied to evaluate the effect of waves and viscosity on the solutions. The focus is placed on verification and validation based on a grid convergence study and comparisons with experimental data. There is also an exploration of the modeling errors in the numerical method.     

自由面和岸壁对限制航道中船舶操纵性水动力的影响

本文在二阶抛物面离散后的船体表面单元上布置强度呈线性分布的Rankine源，在离散后的岸壁单元上和用贴体网格法离散船体附近自由面的单元上布置均匀Rankine源，在船体中纵面上布置强度在水深方向呈阶梯变化的附着涡线．计算了考虑自由而影响下船舶平行于岸壁航行时的水动力，还着重讨论了自由面和岸壁对限制航道中船舶水动力的影响．     

全回转拖轮操纵运动建模与仿真

为提高拖轮操纵模拟器的行为真实感,运用操纵性理论和分离型建模思想,建立全回转拖轮适用于四象限全工况操纵运动的数学模型.通过处理导管桨JD75系列和四象限螺旋桨Nordstrom系列试验图谱后,提出了导管桨四象限推力模型,同时提出了一种适用于全速域的拖轮船体水动力模型.搭建拖轮运动模拟平台,开展一系列操纵性仿真试验,包括速度试航试验、螺线试验、Z形试验、回转试验及停船试验.将仿真数据与Force Techno-logy公司提供的试验数据进行比较分析,一致性良好,表明该模型精度可满足航海上仿真的需要.     

Circular motion tests and uncertainty analysis for ship maneuverability

Circular motion test data and uncertainty analysis results of investigations of the hydrodynamic characteristics of ship maneuvering are presented. The model ships used were a container ship and two tankers, and the measured items were the surge and sway forces, yaw moment, propeller thrust, rudder normal and tangential forces, pitch and roll angles, and heave. The test parameters were the oblique angle and yaw rate for the conditions of a hull with a rudder and propeller in which the rudder angle was set to zero and the propeller speed was set to the model self-propulsion conditions. Carriage data showing the accuracy of the towing conditions in the circular motion test are also presented. It was confirmed that the uncertainties in the hydrodynamic forces such as the surge and sway forces, yaw moment, rudder tangential and normal forces, and propeller thrust were fairly small. The reported uncertainty analysis results of the circular motion test data may be beneficial in validating data quality and in discussing reliability for simulation of ship maneuvering performance.