近接直列2円柱まわりの非定常流

概要

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There are many works on the fluid flow around two circular cylinders arranged in tandem. An interesting phenomenon was found by one of the authors, Igarashi, in the range of L/d=1.2〜1.3,where L is the longitudinal distance between the axes of two cylinders of the same diameter. Namely, the Strouhal number decreases from 0.25 to 0.10 with an increase in the Reynolds number. In the present study, the behavior of the unique flow and the oscillating fluid forces acting on the two cylinders were investigated. The diameter of cylinder, d, was 80 and 100 mm, the distance L/d=1.2,the free stream velocity U ranged from 6 to 20 m/s. The Reynolds numbers were, therefore, 3.1×10^4〜1.3×10^5. The results obtained were as follows : The shear layers separated from the upstream cylinder reattach alternately on the downstream cylinder. A large lift force acts on the reattachment side of the downstream cylinder. There is a phase difference of 4/16 period of the vortex shedding in the oscillating lift of the two cylinders.
一般社団法人日本機械学会の論文
1998-11-25