著者
柴田 和也 越塚 誠一 酒井 幹夫 谷澤 克治 辻本 勝
出版者
公益社団法人 日本船舶海洋工学会
雑誌
日本船舶海洋工学会論文集 (ISSN:18803717)
巻号頁・発行日
vol.11, pp.125-136, 2010 (Released:2011-01-28)
参考文献数
19
被引用文献数
1

A transparent boundary condition was developed for calculating water waves propagating to a distant area by using a particle method. In front of the boundary, the incident waves were analyzed by Fourier analysis, and the particles on the transparent boundary were forced to move to absorb the incident waves. The characteristics of this study are to introduce the technique of wave analysis used for the wave tanks to the particle simulation and to reduce the calculation cost by employing an inflow and outflow boundary. Water waves were calculated in two wave periods by the developed transparent boundary condition. As the results, it was shown that this transparent boundary transmitted the incident waves without the reflection waves. It was also shown that the calculation cost was smaller than that of the ordinary high viscosity boundary condition.
著者
丹 康弘 タン ジュークイ 石川 聖二
出版者
公益社団法人 日本船舶海洋工学会
雑誌
日本船舶海洋工学会論文集 (ISSN:18803717)
巻号頁・発行日
vol.21, pp.75-81, 2015 (Released:2015-10-15)
参考文献数
17

This paper proposes a high-precision real-time correction sounding system using Micro Electro Mechanical Systems (MEMS) inertial measurement units, which can correct the effective depth from the sea surface to the seabed in real-time. The advantages of the proposed system are as follows: (1) The system outperforms a single-beam sounder available on the market in that the range of depth errors caused by the swing of a research vessel is about 2%: (2) Since the proposed system is small compared to the existing attitude and heading reference system, it can be employed for unmanned surface vehicle, remotely operated underwater vehicle, autonomous underwater vehicle, and so on. Experimental results show that an attitude, heading and depth measured by the developed system are within the acceptable range, and the system can give a stabilized attitude, heading and depth information for a long time.
著者
松本 亙平 齋藤 年正 田野 博
出版者
公益社団法人 日本船舶海洋工学会
雑誌
関西造船協会誌 (ISSN:03899101)
巻号頁・発行日
vol.233, pp.129-134, 2000
参考文献数
4
被引用文献数
1

In vibration design of resonant avoidance to fore and aft vibration of superstructure, it is an important technology to estimate accurate natural frequency and to avoid it from resonant zone of blade or cylinder frequency in case of resonance. In this second report, authors investigated coupled vibration effect of local vibrating body such as funnel or dodger upon natural frequency of superstructure. By connecting funnel casing and deck of superstructure, natural frequency of superstructure becomes extremely high when its fundamental frequency exists higher than that of funnel. It is shown that this phenomenon can be applicable to avoid resonance in actual ship design of superstructure vibration. Long wings(dodgers)which exist at navigation bridge deck also affect the natural frequency of superstructure. Coupled vibration effect of dodger is found to lower natural frequency of superstructure.
著者
佐久 間俊 成瀬 俊宏
出版者
公益社団法人 日本船舶海洋工学会
雑誌
日本船舶海洋工学会論文集 (ISSN:18803717)
巻号頁・発行日
vol.22, pp.229-233, 2015 (Released:2016-02-29)
参考文献数
6
被引用文献数
1

This report deals with the stability of ships having comparatively large projected lateral area above water line and shallow draft. Such ships usually have wide breadth because they have tendency to raise their center of gravity. Large GM made by the wide breadth brings strong stability. But it gets weaker if the ship has higher center of gravity because GM/(OG+T/2) becomes smaller. A research challenge of this report consists of the procedure to clarify the acceptable center of gravity and how breadth and draft to be examined and determined. These procedures enable the optimization method in the initial design. In the analysis, the metacenter is estimated by Ohgushi’s and Morish’s formula and the accuracy of the estimation is confirmed using merchant ships’ data released for public. The present method obtained by the analysis shows effectiveness to find out reasonable dimensions and acceptable height of center of gravity in the early stage of ship design.