1986 Fiscal Year Final Research Report Summary
Research of the Calculation Method for the Free Surface Flow around a Ship Hull
| Project/Area Number |
59460130
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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 | YOKOHAMA NATIONAL UNIVERSITY |
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Principal Investigator |
MARUO Hajime Yokohama National University, Professor, 工学部, 教授 (30017842)
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| Co-Investigator(Kenkyū-buntansha) |
TAKUSAGAWA Zensuke Yokohama National University, Assistant, 工学部, 助手 (60017902)
SUZUKI Kazuo Yokohama National University, Assistant professor, 工学部, 助教授 (80111699)
IKEHATA Mitsuhisa Yokohama National University, Professor, 工学部, 教授 (10114969)
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| Project Period (FY) |
1984 – 1985
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| Keywords | Hydrodynamics / Free surface / Wave / Ship resistance / Slender body theory / Non-linear effect / Boundary element method / 水槽試験 |
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| Research Abstract |
This research project consists of three problems:
1) Application of the slender body theory to the free surface flow around a ship hull in steady forward motion.
Preliminary investigation has been carried out until 1983 and the theoretical formulation has been completed, but there still remain problems with respect to the computation method. The present study intends the development of the program for practical computation of the wave pattern, streamlines on the hull surface, pressure distribution and the wave resistance. The analysis is extended to the case of a ship moving with a constant yaw angle. Some test computations have been carried out, but it is found that further improvement is necessary in order to attain a satisfactory accuracy.
2) Numerical solution of the boundary value problem with non-linear free surface conditions for the flow around a ship in steady motion.
Based on the low speed solution as the first approximation, an iterative method is devloped to calculate the solution which satisfies the non-linear boundary condition on the free surface. Computations of the wave profile, pressure distribution on the hull surface and the wave resistance of hull forms expressed by simple equations and a Series 60 model are carried out. Comparison with measured results shows an excellent agreement and the feasibility of this method for the practical application is proved.
3) Analysis of the flow phenomena around the bow of ship models.
Experimental observation of the free surface flow around the bow of models in the towing tank shows the importance of the surface tension effect, by which the free surface configuration and the resistance of the model are seriously influenced. This fact is very important in connection with the correlation between resistance of models and full-scale ships. Theoretical analysis is carried out for the effect of surface tension to the wave pattern and the law of similitude of the resistance.
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Research Products
(8 results)
