1998 Fiscal Year Final Research Report Summary
Study on Estimation of Deck-Wetness for a High-Speed Vessel
| Project/Area Number |
08405065
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
船舶工学
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
TAKAKI Mikio Hiroshima University, Engineering, Professor, 工学部, 教授 (00038556)
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| Co-Investigator(Kenkyū-buntansha) |
LIN Xin Hiroshima University, Engineering, Research Associate, 工学部, 助手 (20263725)
IWASHITA Hidetsugu Hiroshima University, Engineering, Associate Professor, 工学部, 助教授 (60223393)
DOI Yasuaki Hiroshima University, Engineering, Associate Professor, 工学部, 助教授 (10134454)
SAITO Kimio Hiroshima University, Graduate School for International Development & Cooperatio, 大学院・国際協力研究科, 教授 (50029279)
BABA Eiichi Hiroshima University, Engineering, Professor, 工学部, 教授 (30274129)
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| Project Period (FY) |
1996 – 1998
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| Keywords | 3-D rankine panel method / Collocation method / Steady wave profile at bow / Knuckle line / Bow flare form / forward speed effect / Interaction effect / Unstable motion |
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| Research Abstract |
We have performed the Research Project titled "Study on Estimation of Deck-Wetness for a High-Speed Vessel" for three years (1996 - 1998). The main conclusions obtained in this study are summarized as follows :
(1)It was made clear that steady flow around a ship strongly affects unsteady hydrodynamic forces on a ship. We developed the new method predicting the interaction effect between them. It was made clear from this study that the second derivative term of steady flow potential plays important role on hydrodynamic forces.
(2)We developed 3.D linear rankine panel method to predict the interaction effect between the steady and unsteady flow as a practical estimation method. Furthermore, it was made clear from the comparison with experimental results that this method was useful for predicting the seakeeping qualities of a high-speed vessel.
(3)The steady flow strongly affects on radiation forces rather than diffraction forces. In particular, it strongly appears on them in the low frequen
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cy range.
(4)The influence of steady flow has to be taken into account not only the free surface condition but also the ship hull surface condition to estimate accurately the pressure distribution on a ship.
(5)The amplitudes of diffraction waves at bow part can be reduced by the knuckle at bow part. Thereby it is desirable to attach the knuckle at bow part to decrease the deck wetness on a high. speed vessel.
(6)The influence between steady flow and unsteady flow becomes more remarkable as the forward speed increases. In particular, wave profile around bow part is strongly affected by the bow flare form. Thereby, It is necessary to develop a new predicting method which can take into account the effect of bow flare form above the still water surface in order to predict accurately seakeeping qualities of a high-speed vessel.
(7)It was made clear that most of accidents for high-speed vessels are strongly related to unstable motions of high-speed vessels. Thereby, it is urgent to make clear hydrodynamic phenomena generating the unstable motions. Less
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