Unsteady Flow around Two-Dimensional Circular Cylinder Row in Fluid Elastic Vibration

We describe the unsteady flow around two-dimensional circular cylinder row supported by the leaf spring in the fluid-elastic vibration. The experiment was carried out in a circuit-type wind tunnel having a 200mm×200mm working section of 2000mm length at the Reynolds number Re of 8820. Two-dimensional circular cylinders with diameter D=20mm were aligned at regular spaces S in a single row normal to the main stream. The spacing ratio between two adjoining circular cylinders was constant as S/D=1.5 for the unsteady flow measurement. The time-mean velocity was measured by use of a laser Doppler velocimeter. The unsteady flow pattern around an oscillating cylinder was observed by the flow visualization in a water channel. Consequently, it was found that the occurrence of the fluid-elastic vibration is caused by the phenomenon of jet-switch for the circular cylinder row.