表面大変形を伴う円筒容器内の回転流れの不安定性解析(境界層・せん断流・遷移(4),一般講演)

概要

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We analyzed the temporal variation of the surface shape of water in an open cylinder driven by constant rotation of the bottom. In a range of Reynolds number, the surface deformation of the order of the container size shows an aperiodic switching between an axisymmetric surface shape and a nonaxisymmetric surface shape. Time-series analysis of the surface height clarify the characteristics of the flow also switches between laminar and turbulent during the switching process. We also analyzed the variation of turbulent intensity with respect to Raynolds number with a different setup using different material. It is found that the transition Reynolds number is shifted significantly, and that the surface shape shows an intermittent destabilization preceding to the transition. To understand the effect of the material difference, we derived an equation which describes the dynamics of the free surface near the bottom by using a thin-film theory.
2007-08-06