429 一様流中の十字交差二円柱から周期的に流出する縦渦の一般性の検証(S35-3 乱流渦構造(3),S35 乱流渦構造)  [in Japanese] 429 Experimental study on universality of Longitudinal Vortices Shedding Periodically From Crisscross Circular Cylinder System in Uniform Flow  [in Japanese]

In the previous works, the present authors showed that two types of longitudinal vortex shed periodically from a crisscross cylinder system composed of two 26mm diameter circular cylinders based on hot wire anemometry in a wind tunnel with 320mm square cross section together with visualization in a low velocity water tunnel with 200mm square cross section. The specific aim of this work is to confirm universality of this phenomenon by carrying out experiments with larger cylinder diameters and a high-velocity water tunnel. These experiments show that the longitudinal vortex sheds from systems with d=10〜127mm, i.e. the trailing vortex sheds when gap-to-diameter ratio s/d is from 0 to 0.25 and the necklace vortex sheds when s/d is from 0.25 to 0.5. The relationship between Strouhal number for their shedding frequency and Reynolds number is consistent qualitatively with me previous research works regardless of experimental conditions.