Vortex- and Wake-Induced Vibrations of a Circular Cylinder Placed in the Proximity of Two Fixed Cylinders

Abstract

Purpose: This study aims to understand the vibratory response of a circular cylinder placed in proximity to other fixed bodies. Methods: A circular cylinder model was placed in a circulating water channel and was supported elastically to vibrate in the water. Another two circular cylinders were fixed upstream of the vibrating cylinder. The temporal displacement variations of the vibrating cylinder were measured and processed by a frequency analysis. Results: When the inline spacings were small, two amplitude peaks appeared in the reduced velocity range 3.0–13.0. When the inline spacings were large, the amplitude response showed a single peak. Conclusion: For small inline spacings, the first peak was attributed to high-amplitude vibrations forced by Karman vortex streets shed from the upstream cylinders. The second peak arose from interactions of the wakes of the upstream cylinder with the vibrating cylinder. When the inline spacing increased, the vortex-induced vibrations resembled those of an isolated cylinder.