Vortex-induced vibrations by axial flow in a bundle of cylinders

This contribution investigates the occurrence of vortex streets caused by axial flow in bundles of cylinders and the vibrations they trigger using numerical simulations. The vortex streets originate from the difference in axial flow speed in the gap between cylinders and the subchannel center. The dependence of this flow instability on typical parameters such as mean convection velocity and pitch-over-diameter ratio will be investigated. In a following part, two way coupled fluid-structure interaction simulations will be used to predict the vibration of flexible cylinders mounted in these channels. These simulations show that cylinders at the border of the bundle experience stronger oscillations. The influence of stiffness on vibrational amplitude is also tested in a parameter sweep.