721 セレイティッドフィン付き円柱からの渦放出に及ぼす螺旋状側板の効果(後流渦励起振動のメカニズム,OS-5 流体関連振動のメカニズムと計測制御(1))

Abstract

The purpose of this paper is to clarify the effects of helical strakes around a serrated-fin tube on the vortex shedding. It was made clear that Karman vortex was clearly formed even in the case of a fin tube with helical strakes. The existence of helical strakes around a fin tube caused the decrease of the vortex shedding frequency and the increase of the periodicity of vortex shedding from a fin tube. The coherent scale of vortex in the spanwise direction is larger in the case with helical strakes compared with that of a serrated fin tube.