両側円板の回転を伴う円筒容器内の渦崩壊(流体工学,流体機械)

概要

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The swirl flow in an enclosed cylindrical container was investigated for the case of both endwalls independently rotating. Present flow depends on the aspect ratio H/R and the Reynolds number Re based on the rotation of top endwall and Re_b based on bottom endwall or the rotational ratio Ω_b/Ω(Ω_b<Ω), where H the depth of fluid, R radius of endwalls, and Ω_b, Ω respectively the angular velocity of the bottom and top endwall. Experimental visualization and numerical simulation revealed that in the case of endwalls co-rotating the flow tends to promote the vortex breakdown, whereas for the counter-rotating case the vortex breakdown tends to be suppressed. Experiments and numerical solutions have defined the critical boundaries which divide the breakdown area from non-breakdown on Re - H/R map for co- and counter-rotation case at constant Re_b. Flow visualization captured the vortex ring which have been predicted only by numerical studies. Numerical calculation revealed that the divergence of stream lines which lead to the occurrence of the recirculation zone was dependent on the distribution of the centrifugal force. The effects of co- and counter-rotation on the vortex breakdown were appeared as the dissipation of angular momentum on the bottom endwall.
一般社団法人日本機械学会の論文
2003-08-25