レイノルズ数Reが500〜10^4の突然出発する円柱まわりの流れ : 第1報,渦領域の構造と過度の供給機構

概要

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Developments of vortices behind a circular cylinder with its impulsive start were investigated by flow visualization techniques. Special attention was paid to elucidating the relation between the structure of vortices and the Reynolds number Re, from the viewpoint of the convection of the vorticity generated on the surface of the cylinder. The structure of the vortices vary considerably with the Reynolds number immediately after the start of the cylinder for the duration, τ<1〜1.5, where τ is the nondimensional elapsed time. In a high Reynolds number, the separated shear layers roll up close to the separation points and form intense vortices near the rear surface of the cylinder. For Re>3000, the separated vortices induce not only secondary vortices but also tertiary vortices near the separation points. After a duration of τ>1.5, the variation of the structure of the votices with Re was found to be small. The ratio of the circulation to the area of vortex region indicates nearly a constant value.
社団法人日本機械学会の論文
1988-06-25