| Project/Area Number |
23650381
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Sports science
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| Research Institution | University of Tsukuba |
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Principal Investigator |
ASAI Takeshi 筑波大学, 体育系, 教授 (00167868)
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| Co-Investigator(Kenkyū-buntansha) |
KOIKE Sekiya 筑波大学, 体育系, 准教授 (50272670)
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| Project Period (FY) |
2011 – 2013
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| Project Status |
Completed (Fiscal Year 2013)
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| Budget Amount *help |
¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Fiscal Year 2013: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2012: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2011: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
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| Keywords | スポーツ / 流体 / サッカー / ボール / 可視化 / 渦 / 揚力 / 抗力 / 空力 / 空気 / ナックル / 追尾 / PIV / 非定常 / トレーサー |
|---|
| Research Abstract |
A thin smoking agent was applied to a soccer ball to make the vortex flow around the ball in actual flight visible, and images were captured from behind by using a high-speed video camera (1,000 fps). Two-dimensional vector diagrams depicting slipstreams of the ball featured a phase in which a pair of vortices were observed as large-scale vortex structures, as well as a phase in which the large-scale vortex structure was unclear. Based on an analogy between wingtip vortices and the large-scale structures of these vortices, a lift force related to downwash was speculated to have occurred. The lift force due to such a large-scale vortex pair structure can at times slowly rotate the ball, whose major axis is in the direction of movement, in the axial direction. This was considered to be a potential cause for the slight wobbling of the ball.
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