432 円形浮力噴流中の渦構造の挙動 : 可視化実験による観察(S35-3 乱流渦構造(3),S35 乱流渦構造)  [in Japanese] 432 Behavior of Vortex Structure in a Round Buoyant Jet : Visualization Experiments  [in Japanese]

Vortex structures were investigated in a round buoyant jet by smoke-wire visualization and hotwire measurement. Heated air of 53℃ was ejected from a round exhaust of D=83mm. At the exhaust, mean velocity distribution was tophat-type and its mean velocity, U_0, was 2m/s. Ring vortex structures were generated around the exhaust in the buoyant jet. Unlike the usual case of an unheated jet, large vortex structures generated by the vortex pairing of the ring vortices weren't observed. The heated air rose meandering in the potential core. As a result, the buoyant jet became to be turbulent in 2〜3D times downstream from the exhaust. The behavior of the coherent vortices of the buoyant jet was apparently different from the unheated jet.