In this paper we describe the flow around two-dimensional circular cylinder bundles supported by wires. The experiment was carried out in an N. P. L. blow-down wind-tunnel with a 500mm×500mm×2000mm working section, and with Reynolds number 9.4×103. The displacement of a vibrating circular cylinder, and the time mean surface pressure distributions on the circular cylinder were measured. The results were compared with those for the cases of a fixed test cylinder and a flexible test cylinder only which is supported by elastic wires, in fixed circular cylinder bundles. It was found that (i) the critical value of the fluid elastic vibration is obtained as the spacing ratio D/S for a single row, two rows and three rows, and (ii) the lift coefficient becomes nearly zero for a vibrating cylinder mentioned in (i), while it increases for the case of a fixed cylinder.
