Effect of a Vibrating Upstream Cylinder on a Stationary Downstream Cylinder

Abstract

The flow around two circular cylinders in tandem arrangement in uniform flow where the upstream cylinder is forcibly vibrated in direction normal to the approach flow was experimentally studied at Reynolds number of 6.54 × 104 . The spacing ratio 1/d (1: distance between centers of cylinders, d: diameter of circular cylinders) and the ratio of amplitude to cylinder diameter a/d (a: amplitude of transverse vibration of cylinder) were varied from 2 to 6 and 0 to 0.029 respectively. The effects of the vibration of the upstream cylinder on the downstream cylinder were discussed. In particular, two distinct “lock-in” regions were observed when the upstream cylinder was vibrated with a spacing ratio of 1/d = 3.0. The cylinder vibration was so effective even for a/d as small as 0.017 to cause two different flow patterns.