2003 Fiscal Year Final Research Report Summary
The Effect of Ground Roughness on Generation and Flow Patterns of Moving Fire Swirl
| Project/Area Number |
12650504
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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 | Utsunomiya University |
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Principal Investigator |
IKEDA Hirokazu Utsunomiya University, Faculty of Engineering, Associate Professor, 工学研究科, 助教授 (20202898)
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| Project Period (FY) |
2000 – 2003
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| Keywords | fire / fire swirl / plume / general wind / ground roughness / ground boundary layer / vortex / visualization |
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| Research Abstract |
Moving fire swirl is to be generated by interaction of the upward flow from fire region and general wind around the fire region. The purpose of this research is to clarify, in laboratory experiments, the effect of ground roughness on the flow patterns and flow field of the moving fire swirl. At first, experimental method was established to realize those phenomenon like moving fire swirl in the water flume experiment, that is, we injected steady upward flow into the flume flow from the bottom. The flow patterns were visualized with dye. The flow field was measured with electro-magnetic anemometer or image processing. The main result of this research is as follows.
1)Moving fire swirl is generated only when the upward flow from the fire region is strong enough compared to the general wind. The flow patterns are divided into the fixed vortex type and shrunk vortex type by the Reynolds number with general wind velocity and fire region width. The effect of the ground roughness is to weaken the strength of the general wind.
2)In the Fixed vortex type, strong currents toward upstream and upward are generated behind the fire region, which also generated intense turbulence.
3) In the shrunk vortex type, each vortex moves down with decrease its votice and increase of an upward current.
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