Ocean Research Institute, University of Tokyo
Ocean Research Institute, University of Tokyo
Ocean Research Institute, University of Tokyo
Ocean Research Institute, University of Tokyo
Ocean Research Institute, University of Tokyo
出版者
宇宙航空研究開発機構
出版者（英）
Japan Aerospace Exploration Agency (JAXA)
雑誌名
宇宙航空研究開発機構特別資料: 境界層遷移の解明と制御研究会講演論文集 第33回・第34回
雑誌名(英)
JAXA Special Publication: Proceedings of the 33rd and 34th JAXA Workshops on Investigation and Control of Boundary-Layer Transition
巻
JAXA-SP-04-002
ページ
47 - 50
発行年
2005-01-28
抄録（英）
Velocity field measurements and visualization are applied to a sink vortex of water (with a free surface on top) produced in a cylindrical tank rotating about the vertical axis. The controlling parameters are the rotating rate of the tank (0.2 and 0.4 rad s(sup -1)) and the volume flux of a water withdrawn from a hole at the center of the bottom (50 and 150 cu cm s(sup -1)). It is found that a Rankine-like vortex is produced in the steady state when the volume flux of water withdrawn from the hole is large. When the volume flux is small, however, the conservation of the angular momentum around the central axis of the vortex is not established. A simple theoretical model that assumes Ekman boundary layer on bottom plate turns out to reproduce successfully the nonconservation of angular momentum. The injection of fluorescence dye at the periphery of the cylindrical tank reveals that the water introduced at the periphery of the tank descends to the bottom along the side wall and flows to the center of the tank in the boundary layer at the bottom of the tank. However, the dye ascends in a thin vertical layer around the core of the vortex suggesting that the upward flow is formed surrounding the sink vortex. When a rotation rate of the tank is reduced from 0.4 rad s(sup -1) to 0.2 rad s(sup -1) with keeping the withdrawal rate of the water (to maintain a vortex) constant, horizontal plumes appear near the side wall because of the inertial instability. They penetrated a limited extent into the interior region, so that there appears a mixing layer near the periphery of the tank. At the same time nearly-axisymmetric disturbances develop from the bottom boundary layer and intrude into the interior region.
吸い込み渦の境界層と不安定現象
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