Flow-induced oscillations of three tandem circular cylinders in a two-dimensional flow

• Published in: Journal of fluids and structures Vol. 91; p. 102711
• Main Authors: Behara, Suresh, Chandra, Venu, Ravikanth, B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2019
• Subjects: Cylinder trajectories; Flow-induced oscillations; Hysteresis; Lock-in; Primary vortex shedding; Lock-in; Cylinder trajectories; Primary vortex shedding; Hysteresis; Flow-induced oscillations
• ISSN: 0889-9746; 1095-8622
• DOI: 10.1016/j.jfluidstructs.2019.102711

Flow-induced oscillations of three identical circular cylinders, arranged in tandem configuration, are studied via two-dimensional finite element computations. Cylinders are mounted on elastic supports in the streamwise and transverse directions. Each downstream cylinder is placed at a distance of 5 diameters (5D) from its immediate upstream neighbor. Nondimensional mass ( m∗) of 2, and zero damping (ξ) are considered. Simulations are performed with the objective of understanding dynamic response of cylinders, as they are subject to wake interference, at constant Reynolds number, Re=150, and for varying reduced velocity (U∗) in the range of U∗=2−14. Similar to the behavior of an isolated cylinder at low Re, oscillation response of the upstream body exhibits initial excitation and lower lock-in regimes. However, for both the downstream cylinders, depending on their amplitude and frequency responses, the synchronization regime of U∗ can be categorized into three distinct regions: initial excitation, upper and lower lock-in regions. First downstream cylinder undergoes gradual transition between initial excitation and upper region, whereas the second downstream body exhibits this transition in two phases, which are separated by a periodic oscillation response regime. Upper lock-in region is characterized by periodic oscillations, while amplitude is modulated in the lower region. Only 2S shedding mode is observed for all the U∗ considered.