Abstract
Authors reported that flip-flop flows having the self-excited oscillations are induced by the rotation of the vortex in the concavities constructed on both sidewalls inside the diamond-shaped cylinder bundle. Experiments of the flow visualization are performed for flip-flop flows exiting from diamond-shaped cylinder bundles. Comparison is carried out using the measured results in the absence or presence of the concavities constructed on both sidewalls inside the diamond-shaped cylinder bundle. It is found from the study that (i) flip-flop flows are mutually spread on left or right direction at the angle of 30°, that is the diverging angle of the jet-stream from the bundle becomes 60°, and (ii) the diffusion phenomenon in the jet-stream is quantitatively disclosed by different bundle shapes.
