Collective Behavior of Free-Oscillating Cylinders in Cross-Flow

The collective behavior of progressively increasing numbers of free-oscillating cylinders is studied numerically using computational fluid dynamics. The 1-DOF cylinders are free to oscillate in the direction perpendicular to the direction of incoming flow with no structural damping and no stiffness. They are placed in a uniform cross-flow with a Reynolds number of 100, defined using the diameter of one of the identical cylinders. A fixed cylinder is positioned upstream as the leader, allowing a consistent upstream wake before each of the free-oscillating cylinders downstream. The patterns of vortex shedding as well as lift and drag are analyzed in each of the various configurations utilized in this study. Configurations include symmetric circular, triangular, and rectangular arrays as well as asymmetric arrangements. The comparisons between fixed and free-oscillating cylinder configurations serve to highlight the energy-saving reconfigurations present when there is no stiffness or damping of the structures.