The Interaction Vortex Flow Around Two Bluff Cylinders

Abstract

In this study, the interaction vortex flow features around a pair of parallel arranged bluff cylinders were observed by visualizing water flow experiment at the range of the gap ratio G/d=0~3. It was obtained that the result of established wind tunnel test and the result of this water tank test agreed about the characteristics of vortex shedding when varying the distance of circular cylinder gap. The flow pattern and vortex shedding frequency of another type bluff cylinder (triangular and square cylinder) were also investigated. As a result of the experiment, it was shown that the flow pattern of wake flow was divided into three kinds (coupled vortex streets, biased gap flow and single vortex street) regardless of the cylinder section shape and cylinder size. Then, the region of the appearance of flow pattern was shown about each case. In the case where two each other independent vortex streets were formed, three typical flow patterns of vortex formation (in-phase coupled vortex streets, out-of-phase coupled vortex streets and complication coupled vortex streets) were observed. It was known that three configuration of vortex formation appear intermittently and alternatively.