1998 Fiscal Year Final Research Report Summary
PREDICTION OF BOTH DANGER ZONE OF FLOOD AND ACCUMULATION DISTRIBUTION OF VOLCANIC ASH IN REVERE BY MEANS OF LAGRANGE METHODS
| Project/Area Number |
09650570
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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 | KAGOSHIMA UNIVERSITY |
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Principal Investigator |
TORII Shuichi KAGOSHIMA UNIVERSITY,ENGINEERING,ASSOCIATE PROFESSOR, 工学部, 助教授 (30180201)
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| Co-Investigator(Kenkyū-buntansha) |
YANO Toshiaki KAGOSHIMA UNIVERSITY,ENGINEERING,PROFESSOR, 工学部, 教授 (60002052)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Volcanic Ash / Shirasu / Solid-Liquid Phase Flow / Numerical Analysis / Revere Improvement / flow around a bridge pier / 現地調査 |
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| Research Abstract |
An experimental and numerical study has been performed to predict both the danger zone of flood and the accumulation distribution of volcanic ash in reveres. The experimental apparatus used here was consisted of a rectangular open channel (simulating a revere with a 2-D flow field in the streamwise and normal directions) with a side wall which Was made of acrylic windows for illumination and observation. In particular, the flow characteristics around the plate (simulating a bridge pier) is observed using a CCD camera and an image processing. The corresponding numerical analysis was carried out using the governing equations, which are discretized by means of a finite-difference technique to determine streamwise and transverse velocity components. The roles of both the Reynolds number and the ratio of the slot width, d, to its thickness, delta, on the velocity field are disclosed. It is found from the study that : (i) at a small value of Re and/or d/delta, the flow field over the slot exhibit no timewise variation, (ii) when Re and d/delta exceed certain values, an alternate crossing of flow from one side of the plate to the other occurs across the slot and (iii) the alternating change in the fluid flow disturbs the velocity boundary layer formed along the plate and induces mixing of the upper and lower streams of the plate downstream from the slot. These results in the velocity field are confirmed by the flow visualization using ion-exchange resins.
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Research Products
(16 results)
