吸い込み渦の構造と力学 : 底面境界層の重要性(回転(2),一般講演)

概要

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A bathtub vortex in a cylindrical tank rotating at a constant angular velocity Ω is studied by a laboratory experiment, a numerical experiment and a boundary layer theory. When the volume flux Q is large and Ω is small, a vortex in which angular momentum is constant outside the vortex core is formed (Regime I). When Q is small or Ω is large, however, one in which the angular momentum decreases with decreasing radius occurs (Regime II). When the ratio of Q to the theoretical boundary-layer radial flux Q_b (scaled by 2πR^2(νΩ)^<1/2>. for a potential vortex) at the radius of the drain hole is larger than a critical value (of order 1), the radial flow in the interior exists at all radii and Regime I is realized. When the ratio is less than the critical value, the radial flow in the interior nearly vanishes inside a critical radius and almost all of the radial flux occurs in the boundary layer, resulting in Regime II.
日本流体力学会の論文
2008-09-04