共查询到20条相似文献,搜索用时 15 毫秒
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文章基于粘性流体理论,采用CFD技术,通过对双体船变漂角旋臂运动的模拟,得到代表小水线面双体船舶操纵性能的水动力导数。利用MMG模型,对小水线面双体船的操纵性能进行初步预报。根据变漂角旋臂运动的数值模拟,既可从中得到仅仅与漂角和角速度有关的水动力导数,也可获得包括高阶导数和耦合导数在内的操纵性运动水动力导数。文章在保留三阶水动力导数的情况下,将代入高阶耦合水动力导数的操纵运动方程所绘制的回转圈与不代入高阶耦合水动力导数的回转圈进行对比,体现了高阶耦合水动力导数对于小水线面双体船操纵性预报的重要性,并以某双体船型为例,对其操纵性能进行预报。 相似文献
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《船舶与海洋工程学报》2021,(3)
This paper proposes a semi-empirical model to predict a ship's speed loss at arbitrary wave heading.In the model,the formulas that estimate a ship's added resistance due to waves attacking from different heading angles have been further developed.A correction factor is proposed to consider the nonlinear effect due to large waves in power estimation.The formulas are developed and verified by model tests of 5 ships in regular waves with various heading angles.The full-scale measurements from three different types of ships,i.e.,a PCTC,a container ship,and a chemical tanker,are used to validate the proposed model for speed loss prediction in irregular waves.The effect of the improved model for speed loss prediction on a ship's voyage optimization is also investigated.The results indicate that a ship's voyage optimization solutions can be significantly affected by the prediction accuracy of speed loss caused by waves. 相似文献
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Vishwanath Nagarajan Dong Hoon Kang Kazuhiko Hasegawa Kenjiro Nabeshima 《Journal of Marine Science and Technology》2008,13(1):24-39
A simulation model of a very large crude carrier (VLCC) with either a mariner type Schilling rudder or a mariner rudder was
developed from captive and free-running model tests. Kijima’s regression formula was used to predict the hydrodynamic hull
forces on the VLCC. To simulate full-scale maneuvering at cruising speed, the constant torque operation of the main engine
was assumed. Considering the higher normal lift force and maneuverability of the mariner type Schilling rudder as compared
to the mariner rudder, the size of mariner type Schilling rudder is kept smaller as compared to mariner rudder. To compare
the efficiency of the two types of rudder system, maneuvering simulations at constant engine torque and course-keeping simulations
at various gusting wind speeds and encounter angles were carried out. Based on the simulation results, the two rudder types
were compared from the viewpoint of maneuvering and fuel efficiency in windy conditions. 相似文献
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Study on the maneuverability of a large vessel installed with a mariner type Super VecTwin rudder 总被引:1,自引:1,他引:0
Kazuhiko Hasegawa Donghoon Kang Masaaki Sano Kenjiro Nabeshima 《Journal of Marine Science and Technology》2006,11(2):88-99
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 (tR, aH, xH) 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. 相似文献
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何小惠 《交通部上海船舶运输科学研究所学报》2008,31(2):128-131
详细介绍了166客位玻璃钢高速客船的研制情况,重点探讨了该船关键技术:船型及船舶主尺度的选取;线型、船体材料的选用;船体结构的优化设计以及主要机电设备的配置。同时,给出了实船的测试结果。 相似文献
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Under the background of the energy saving and emission reduction, more and more attention has been placed on investigating the energy efficiency of ships. The added resistance has been noted for being crucial in predicting the decrease of speed on a ship operating at sea. Furthermore, it is also significant to investigate the added resistance for a ship functioning in short waves of large modern ships. The researcher presents an estimation formula for the calculation of an added resistance study in short waves derived from the reflection law. An improved method has been proposed to calculate the added resistance due to ship motions, which applies the radiated energy theory along with the strip method. This procedure is based on an extended integral equation (EIE) method, which was used for solving the hydrodynamic coefficients without effects of the irregular frequency. Next, a combined method was recommended for the estimation of added resistance for a ship in the whole wave length range. The comparison data with other experiments indicate the method presented in the paper provides satisfactory results for large blunt ship. 相似文献
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Time-varying coefficient vector autoregressive (T-VVAR) modeling with instantaneous responses is applied to spectrum analysis
based on the nonstationary motion data of ships. Because of the ship's maneuvers, changes such as course and speed, the ship
motions in waves are regarded as a nonstationary random process, although the seaway can be considered as a stationary stochastic
process. The T-VVAR model is transformed into a state space model, and the time-varying coefficients can be evaluated by using
the Kalman filter algorithm. Using the estimated time-varying coefficients, the instantaneous cross spectra of the ship motions
can be calculated at every moment. In order to examine the reliability of the proposed procedure, on-board tests were carried
out. Under stationary conditions, at a constant speed and course, the proposed method shows good agreement with stationary
vector autoregressive (SVAR) modeling analysis. Moreover, it is confirmed that the proposed method can estimate the instantaneous
cross spectra of the ship motions even under nonstationary conditions, showing that this is a powerful tool for on-line analysis
of the nonstationary motion data of ships.
Received: August 2, 2002 / Accepted: November 28, 2002
Acknowledgments. The authors thank the captain and crew of the training ship Shioji Maru, Tokyo University of Mercantile Marine.
Address correspondence to: T. Iseki (iseki@ipc.tosho-u.ac.jp)
Updated from the Japanese original, which won the 2002 SNAJ prize (J Soc Nav Archit Jpn 2001;190:161–168) 相似文献
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《船舶与海洋工程学报》2015,(3)
Centrifugal forces are commonly created when ships turn, which may cause a ship to capsize in a critical situation. A mathematical model has been developed to optimize the stability coefficients for ship, with the aim to prevent capsizing and to increase ship maneuverability in high-speed water craft. This model can be used to develop algorithms for control system improvement. The mathematical model presented in this paper optimized the use of multipurpose hydrofoils to reduce heeling and the trimming moment, maintaining an upright ship's position and lessening the resistance via transverse force. Conventionally, the trimming and heeling of a ship are controlled using ballast water; however, under variable sea conditions it is sometimes difficult to control a ship's motion using ballast water. In this case, a hydrofoil would be more stable and maneuverable than a ballast tank controlled vessel. A movable hydrofoil could theoretically be adapted from moveable aerofoil technology. This study proves the merit of further investigation into this possibility. 相似文献
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寻找一种科学实用的船舶操纵性能综合评价方法一直是船舶研究者、设计者和使用者所追求的目标之一.应用模糊综合评估理论,建立了船舶操纵性能综合评估模型,通过对多条船舶的操纵性能所进行的计算分析表明,应用该模型可以得到符合实际的结论. 相似文献
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Sahbi Khanfir Kazuhiko Hasegawa Vishwanath Nagarajan Kouichi Shouji Seung Keon Lee 《Journal of Marine Science and Technology》2011,16(4):472-490
With a recent increase in ship capacity and propulsion performance, a wide-beam ship fitted with a twin-rudder system has
been adopted in many cases. However, to improve ship manoeuvring, it is still necessary to have a better understanding of
rudder-hull interactions in twin-rudder ships. Captive model tests (oblique towing and circular motion test) as well as free-running
tests with a single-propeller twin-rudder ship and a twin-propeller twin-rudder ship are carried out. The effect of drift
angle on the rudder forces and some peculiar phenomena concerning rudder normal force for twin-rudder ships are evaluated.
A method for estimating the hull-rudder interaction coefficients based on free-running experimental results is proposed. 相似文献
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应用支持向量机的船舶操纵运动响应模型辨识 总被引:1,自引:0,他引:1
建模是评估船舶操纵性和可控性的重要前提.基于自由自航船模试验的系统辨识方法是求取船舶操纵运动数学模型中的水动力系数的有效手段之一.文中提出了一种使用支持向量回归估计的船舶操纵运动响应模型辨识方法,该方法通过训练自由自航试验数据样本得到参数回归模型.辨识和仿真结果验证了文中所提出的方法的有效性. 相似文献
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由于岸壁效应和浅水效应,内河船舶在限制水域作操纵运动时通常受到比在开阔水域中更大的水动力.这些水动力对船舶操纵性具有不利影响,有可能导致船舶碰撞或触底等海上事故.因此,为了在船舶设计阶段预报其操纵性能,考虑浅水效应和岸壁效应以准确计算内河船舶操纵运动水动力非常重要.本文基于CFD方法,通过对粘性绕流进行数值模拟,对长江中营运的三艘内河船舶的操纵运动水动力进行计算.首先,为了验证数值方法的可靠性,对标模KVLCC2纯横荡和纯首摇试验的水动力进行计算,并将计算结果与现有的试验数据进行对比.然后,对三艘内河船舶在不同水深下的静舵试验、纯横荡和纯首摇试验进行数值模拟,计算得到水动力及相应的线性水动力导数.最后,基于计算得到的水动力导数,获得Nomoto模型中的操纵性参数,对比分析三艘内河船舶在深浅水中的操纵性能.结果表明,本文方法可以揭示不同水深下三艘内河船舶的操纵性变化趋势.该方法可为船舶设计阶段内河船舶深浅水中的操纵性预报提供一种实用的工具. 相似文献
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大型船舶浮筒系泊断缆事故分析 总被引:3,自引:0,他引:3
张海文 《交通部上海船舶运输科学研究所学报》1992,(2)
本文以日本MMG非线性数学模型为基础。计入船舶在低速、大漂角运动下的影响,建立了系结浮筒船舶在风压力和流压力作用下的偏荡运动数学模型,然后对“雪海”轮以不同风速、流速和各种系挂方式进行了模拟计算,分析了“雪海”轮断缆的主要原因,提出了安全系泊的措施。 相似文献