Numerical investigations of two vibrating cylinders in uniform flow using overset mesh

Abstract

In this research, flow around two vibrating cylinders in a tandem arrangement is simulated at Reynolds number Re = 200 using the dynamic overset mesh technique in finite volume-based commercial software. This investigation aims to study the combined influences of the spacing between the two identical circular cylinders and their excitation frequency in the flow. The cylinders are excited by a transverse forced vibration in a uniform cross-flow by applying a simple harmonic motion. The gap distance between the vibrating cylinders is chosen to be L/D = 1.5 and 4, and the vibration amplitude is kept constant at A/D = 0.25. The study focuses on three frequency ratios of the cylinders' excitation frequency to Strouhal shedding frequency of the single stationary cylinder f e/f s = 0.8, 1.0, and 1.2. Simulation results showed that the flow characteristics over the two vibrating circular cylinders differ from that of a single vibrating cylinder. Also, it is observed that the lock-in state (resonance) for the two vibrating cylinders and the vortex wake patterns are highly affected by the gap distance between cylinders and the excitation frequency.