1991 Fiscal Year Final Research Report Summary
Study on Effect of Hull-flare Form for Sea-keeping Qualities
| Project/Area Number |
02452187
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
船舶抵抗・運動性能・計画
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| Research Institution | Hiroshima University |
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Principal Investigator |
TAKAKI Mikio Hiroshima University, Faculty of Engineering, Professor, 工学部, 教授 (00038556)
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| Co-Investigator(Kenkyū-buntansha) |
IWASHITA Hidetsugu Hiroshima University, Faculty of Engineering, Research Associate, 工学部, 助手 (60223393)
HIGO Yasushi Hiroshima University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (20156582)
NAKAO Michio Hiroshima University, Faculty of Engineering, Professor, 工学部, 教授 (20034324)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Hull-Flare / Impulse Response / 3-D Panel Method / Improvement of Calculating Accuracy / Neumann-Kelvin Problem / Added Wave Resistance / Mutual Relation to Hull form |
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| Research Abstract |
We have studied on the effect of hull-flare form for sea-keeping qualities since 1990. The main conclusions obtained in this study are summarized as follows :
(1) We have developed the estimating method for the hydrodynamic forces on 2-D body which include the hull flare effect. It has made clear that the effect of hull-flare on the hydrodynamic force is large.
(2) The hull-flare effect on the wave loads and the added wave resistance acting on 3-D body is relatively small. The hull-flare affects on the added wave resistance. In addition to that, the present theory can estimate well the first order force. However, there are some discrepancies between theoretical results and the experimental ones concerning the second order forces such as the added wave resistance and wave pattern around a ship. Therefore, we should develop a new calculating method.
(3) We have derived the validation method of the added wave resistance on the Neumann-Kelvin Problem. We have made clear from the theoretical c
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alculation and the experiment that the new terms should be added to Maruo's formula. The new terms are caused by the inconsistency in the changing rate of momentum and energy flux arising from the intersection on the surface-piercing body with forward speed.
(4) We have developed the calculating method of the kernel function to improve the accuracy of the 3-D hydrodynamic forces due to the 3-D panel method. Furthermore, we have applied it to a ship to check the estimation accuracies of the hydrodynamic forces. It has become clear that a large number of panels on a ship are essential to improve its accuracy.
(5) According to the comparisons between the theoretical results and experimental results on a full ship, the estimating accuracies of the first and second wave forces become worse in the short range. We should investigate the theory furthermore.
(6) We have made clear the mutual relation between the ship hull forms and the sea-keeping qualities. Following this, we have gotten the instruction method improving the ship performance in waves. Less
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