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1.
A study on improving the course-keeping ability of a pure car carrier in windy conditions 总被引:1,自引:1,他引:0
Kazuhiko Hasegawa Donghoon Kang Masaaki Sano Vishwanath Nagarajan Makoto Yamaguchi 《Journal of Marine Science and Technology》2006,11(2):76-87
The course-keeping ability of a pure car carrier (PCC) in windy conditions is discussed in this article. Numerical simulations
of two PCCs were carried out to compare their course-keeping abilities in wind. The two PCCs had the same hull form but different
types of rudder. One PCC was fitted with a semispade rudder (hereinafter, the normal rudder), whereas the other was fitted
with a spade-type Schilling rudder (hereinafter, the Schilling rudder). Both PCCs were designed to a new concept for the accommodation
structure and hull form above the load water line. In this new design concept, there are no sharp corners in the superstructure
so as to reduce wind resistance and improve steering performance. The limits of course keeping for the two PCCs were investigated
through simulations. The course-keeping abilities of the two PCCs, each with two different types of autopilot system, were
also investigated in wind. To develop the numerical simulation, the hydrodynamic coefficients of the two PCCs were predicted
based on the data published for a third PCC having similar principal particulars. The numerical model of the two PCCs was
validated by comparing its behavior with the respective full-scale trial results. Wind resistance coefficients were predicted
by combining the results of wind tunnel experiments of the object PCCs and a regression model. Numerical simulations under
steady wind conditions were also carried out and the results compared with some full-scale experiments to validate the mathematical
model of the PCC. 相似文献
2.
Kenichi Kume Jun Hasegawa Yoshiaki Tsukada Junichi Fujisawa Ryohei Fukasawa Munehiko Hinatsu 《Journal of Marine Science and Technology》2006,11(2):65-75
This article presents hydrodynamic forces and moments, surface pressures, estimated side force distributions, and wakes under
oblique towing conditions for a practical tanker model (model KVLCC2M), which was designed by the Korea Research Institute
of Ships and Ocean Engineering (KRISO). Ship offset data is readily available and can be obtained from the Internet. The model
ship has no appendages and no rudder. Trim and sinkage were adjusted to zero in the static condition and the model ship was
constrained against any motion. Although the drift angle β was primarily set to 0°, 6°, and 12°, other settings were used in some experiments. All experimental results were processed
using uncertainty analysis. The uncertainty analyzing method follows the ANSI/ASME Performance Test Code (PTC19.1-1985) and
the AIAA Standard S-071-1995. Only a few error components were considered here and they were empirically chosen because they
had a heavy weighting when used in the uncertainty calculation. The results of these towing tank experiments will contribute
to the development of computational fluid dynamics (CFD) research in ship hydrodynamics. 相似文献
3.
Kho Shahriar Iqbal Gabriele Bulian Kazuhiko Hasegawa Md. Mashud Karim Zobair Ibn Awal 《Journal of Marine Science and Technology》2008,13(3):282-290
On the basis of previous studies, a series of hazards involving the typical small inland passenger ferries operating in inland
Bangladeshi waters have been identified. In particular, stormy weather conditions, overloading, and the risk of crowding to
one side have been determined as the typical events that are likely to lead to capsizing in the intact condition. In this
article, possible hazard mitigation measures are discussed, both from the regulatory and from the design point of view, for
a small inland ferry that is very similar to one that actually capsized in the past. The addressed design options involve
ballasting and hull modification by means of additional buoyancy above the waterline. From a regulatory point of view, it
is proposed that the present weather criterion in force in Bangladesh be modified by increasing the wind speed to be accounted
for and by considering the concurrent effects of wind, rolling, and the crowding of people to one side. 相似文献
4.
Kho Shahriar Iqbal Gabriele Bulian Kazuhiko Hasegawa Md. Mashud Karim Zobair Ibn Awal 《Journal of Marine Science and Technology》2008,13(3):270-281
The safety of inland passenger vessels operating in Bangladesh has been investigated. By thorough analysis of past accident
data, the main causes of intact stability failures have been determined: adverse weather conditions and overloading, likely
resulting in crowding to one side. Historical series of wind data were gathered and their analysis suggests that an increase
in the wind speed presently used in the Weather Criterion in force in Bangladesh could be advisable. A model of a small passenger
ship typically operated in Bangladesh has been analyzed in order to identify the most relevant hazards under intact ship conditions.
A strongly jeopardizing effect of overloading under intact ship conditions has been detected when analyzing the hazard from
the crowding of people to one side. 相似文献
5.
The mathematical modeling group (MMG) model is well known and is widely used in the field of ship maneuverability. However,
the MMG model can be applied only after determination of the hydrodynamic coefficients either from comprehensive captive model
tests or from general empirical data. Around the cruising speed, when a ship's drift angle is relatively small, several methods
have been developed to predict hydrodynamic coefficients from the ship's principal particulars, e.g., Kijima's method. Kijima's
method is efficient in predicting the ship's maneuverability at the initial design stage and is even able to assess the effect
of changes in stern design. Similarly, for the low speed range when a ship's drift angle is relatively large, several methods
for predicting the ship's hydrodynamic coefficients have been proposed, based on captive model tests, such as those by Kose,
Kobayashi, and Yumuro. However, most of the methods developed for low speeds cannot be applied to general ship types without
additional experiments being performed. In contrast, Karasuno's method uses theoretical and empirical approaches to predict
the hydrodynamic forces, even for large drift motions. Although Karasuno's model utilizes the ship's principal particulars
and is applicable to a general vessel, it has not been widely used. This is because the form of Karasuno's model is relatively
complicated and its accuracy around the cruising speed is less than that for other methods that have been specifically developed
for the cruising speed range. A practical method for predicting hydrodynamic forces for the entire operating speed range of
blunt-body ships is proposed in this article. It is based on the MMG model and predicts hydrodynamic coefficients based on
a ship's principal particulars. A regression model for the proposed method has also been proposed by analyzing 21 different
blunt-body ships. Finally, simulations of a very large 4-m crude carrier (VLCC) model using the proposed method were carried
out and the results compared with free-running experiments (both at the cruising speed and at low speeds) to validate the
efficacy of the model. 相似文献
6.
岳阳 《变流技术与电力牵引》2005,(2):15-18
为使用超导磁体(SCM)的磁悬浮运输系统开发不需接触地面的车上电源,对减少环境污染(噪声和废气的排放)是非常重要的.文章提出了将线性发电机(LG)并入现有SCM以提高输出功率、改善功率因数和测量系统的可行性,并在山梨磁悬浮试验线进行了试验.装在转向架左侧的线性发电机,在400km/h和500km/h的速度范围内,能为磁悬浮车辆提供25kW的电力.分析和运行试验测量的结果有良好的相关性.因此可望将线性发电机投入实际应用. 相似文献
7.
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
8.
Takaaki Hasegawa 《国际交通安全学会研究报告》2018,42(2):40-48
This paper describes various solutions of the traffic society from the viewpoint of the analogy in ICT field and mobility field and the systems innovation theory. The systems innovation theory creates systems by considering both aspects “lifestyle/value of sense” and “fundamentals of mathematical physics/science and technology,” including the platform theory. This paper describes the development of ICT, which may drastically change solutions, with emphasis on the real-world nature. Next, three effective solutions for the era of falling birthrate and aging population are described. In addition, Nakashima's innovative approach for enabling, for the first time, the creation of a new social system by bringing IoT and FinTech into the world of Mobility is described. Finally, Mobility as a Service, which can be realized by integrating traffic modes with ICT, is discussed from the viewpoint of the systems innovation theory including the platform theory. Here, the analogy of mobility field and ICT field is used. 相似文献
9.
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
10.
The comparison of land and inland water transportation from economical and ecological points of view is discussed. Required
freight rates for trucks and ships are calculated and compared to find which has economic superiority. From the environmental
impacts of these two transportation types, the comparative environmental destruction indices for two different time-durations
are estimated. All these investigations were conducted for the Yokohama–Fukuoka route in Japan. Life cycle impact assessment,
a very useful tool for quantitatively evaluating the environmental influence of a product, was used to compare the environmental
burden imposed by these types of transportation. Finally, the way that these results can be used for inland transportation
system planning is discussed.
Received: January 21, 2000 / Accepted: June 27, 2000 相似文献