Abstract
The aim of the present research is to develop the fundamental study on the control of the self-excited oscillations indiamond-shaped cylinder bundles. The PIV measurements are performed on the flow visualization in the horizontal crosssection of the exit jet-stream flow field exiting from diamond-shaped cylinder bundles. Comparison is carried out using themeasured results in the absence or presence of the concavities constructed on both sidewalls inside the diamond-shapedcylinder bundle. It is found from the study that a substantial enhancement of |dV/dy| takes place at Type D60c for thestreamwise diverging diamond-shaped bundle.
