Fluid-structure interactions of two side-by-side circular cylinders

This paper examines the flow-induced vibrations of two side-by-side circular cylinders in a cross flow at two different spacing ratios, and attempts a comparison between measurements and numerical calculations. The two cylinders have fixed mounting at the ends and they are free to move under the action of the unsteady flow-induced forces. The present approach solves the flow field using a finite element method and models the cylinder motions using a two-degree-of-freedom structural dynamics model. An experiment to measure the vibration amplitude of the freely vibrating cylinder has been carried out at the same spacing ratio, reduced velocity, damping factor and mass ratio as the numerical calculations. Good agreement between measurements and calculations is obtained. At T/D = 1.13, an additional vortex shedding is found due to the interaction of the cylinders with the gap flow.