Flow-induced vibration of an elliptical cylinder and a wake-mounted flat plate

Abstract

A numerical simulation is carried out to study flow-induced vibration of an elliptical cylinder equipped with a wake-mounted flat plate in a laminar flow regime at Re = 100. The objects are constrained to vibrate independently in the cross-flow direction. The Vortex-induced vibration of an upstream cylinder with four different aspect ratios (AR = 0.25, 0.5, 0.75, 1) is investigated in the presence of a plate mounted in different horizontal spacing of G = 0.5–3. Simulations are performed for a fixed mass ratio of 10 and negligible damping ratio across a range of reduced velocities (Ur = 2–12). The results demonstrate that the presence of the flat plate can amplify the vibration amplitude of the cylinder by altering the shear layers’ structure, particularly at short horizontal distances. Moreover, the phase difference of the objects shows a correlation with both the horizontal distance and the AR. Furthermore, the presence of the plate results in broader lock-in regimes across all aspect ratios by delaying its end to larger reduced velocities. While reducing the AR leads to a higher maximum vibration amplitude of the cylinder, it results to a considerably lower amplitude for the plate due to different wake structures and reduced interaction between the shear layers and the flat plate.