1998 Fiscal Year Final Research Report Summary
A STUDY ON HYDROELASTIC RESPONSE OF LARGE-SCALE FLOATING STRUCTURE TO WAVES
| Project/Area Number |
09650560
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
水工水理学
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| Research Institution | IWATE UNIVERSITY |
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Principal Investigator |
SAKAI Shigeki IWATE UNIVERSITY CIVIL AND ENVIRONMENTAL ENGINEERING,ASSOCIATE PROFESSOR, 工学部, 助教授 (80091643)
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| Project Period (FY) |
1997 – 1998
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| Keywords | large-scale floating structure / hydrodynamic response / tsunami / random waves / time domain analysis / finite element method / boundary element method / model test |
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| Research Abstract |
A numerical method is developed to analyze the hydroelastic responses of large-scale floating structure to waves. A boundary element method (BEM) is applied to evaluate the fluid motion and a finite element method (FEM) to analyze the elastic deformation of structure. By satisfying the continuity of the displacement and pressure on the fluid-structure interface, the BEM and FEM are combined to simulate the wave-structure interaction. Waves are generated in a numerical water flume by giving the water elevation and the water particle velocity distribution over wave generation boundary step-by-step, and the dynamic responses of structure to waves are calculated in a time domain. Although the analysis in this study is focused on the linear problem, this method can be applied to the analysis under arbitrary wave conditions. Especially, this method is available for the analysis of non-periodic waves, such as a solitary wave for which the previous methods in a frequency-domain can not be appl
… More
ied.
In order to examine the validity and applicability of the proposed numerical approach, laboratory experiments are carried out by using polyethylene plate and polypropylene plate as model floating structures. The validity is verified by comparing the numerical results with experimental data of regular wave, random waves and solitary wave.
It is found experimentally and numerically that a solitary wave under flexible floating structure fissions when the bending rigidity of structure or the ratio of wave height to water depth is large. Furthermore, a train of the fissioned waves propagate like as regular waves. The fission observed in this study is different from the so-called soliton fission on a free water surface, since the fissioned waves appear in front of the main part of the solitary wave. When the fission does not occur, the bending moment acting on the floating structure at the crest of solitary wave is significant as expected from the profile of solitary wave. However, when the solitary wave fissions, the bending moment at the trough of the fissioned waves become much larger than that at the crest. This is very important in the actual design, in particular in the reinforcement of structure against Tsunami. Less
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