Wake patterns of freely vibrating side-by-side circular cylinders in laminar flows.

Wake patterns behind two freely vibrating circular cylinders in side-by-side arrangements are numerically investigated through two-dimensional computational fluid dynamics simulations. The two cylinders, with an equal diameter and a low mass ratio (the cylinder mass/the displaced fluid mass) of 2, can only oscillate in the transverse direction, and they are subject to the uniform laminar flows with the Reynolds number of 100. The center-to-center spacing over a cylinder diameter ratio (s / D) is varied from 2 to 5. For each s / D , the reduced velocity U r (defined by U ∞ ∕ f n D , where U ∞ is the free-stream velocity and f n is the cylinder natural frequency) is varied from 0 to 30. A small parametric increment of Δ U r = 0. 1 and Δ s / D = 0. 1 is considered, providing a comprehensive analysis and insights into the wake patterns of the vortex shedding behind both cylinders. With more than 1500 new simulation cases, 8 distinctive wake patterns are identified through a map of U r and s / D , with several well-defined boundaries governing different flow patterns. Qualitatively distinctive wake characteristics are analyzed through the evaluations of vortex dynamics, hydrodynamic lift/drag forces and cylinder vibration responses. • Wake patterns of two transversely vibrating side-by-side circular cylinders are numerically investigated. • Cylinders with low mass ratio of 2 are subject to uniform laminar flows with Re = 100. • Cylinder spacing ratio is varied between 2 and 5 with small increment of 0.1. • Reduced flow velocity is varied between 0 and 30 with small increment of 0.1. • Over 1500 new simulation cases are characterized into 8 distinctive wake patterns. [ABSTRACT FROM AUTHOR]