Spanwise wake development of a pivoted cylinder undergoing vortex-induced vibrations with elliptic trajectories

• Published in: Experiments in fluids Vol. 60; no. 5; pp. 1 - 15
• Main Authors: Marble, Erik, Morton, Chris, Yarusevych, Serhiy
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2019; Springer Nature B.V
• Subjects: Circular cylinders; Computational fluid dynamics; Dislocations; Engineering; Engineering Fluid Dynamics; Engineering Thermodynamics; Fluid flow; Fluid- and Aerodynamics; Heat and Mass Transfer; Particle image velocimetry; Research Article; Reynolds number; Shedding; Topology; Trajectories; Velocity measurement; Vortex-induced vibrations; Vortices
• ISSN: 0723-4864; 1432-1114
• DOI: 10.1007/s00348-019-2725-2

The wake development of a pivoted circular cylinder undergoing vortex-induced vibrations with elliptical trajectories is examined experimentally at a fixed Reynolds number of 3027 and mass ratio of 10.8. Simultaneous cylinder displacement measurements and time-resolved, two-component particle image velocimetry in multiple horizontal and vertical planes are used to quantify the structural response and wake development. The selected test cases pertain to U ∗ = U 0 / f n D = 5.48 and 7.08, and exhibit different orientations of elliptical cylinder trajectory, both with a clockwise direction of orbiting. Three-dimensional reconstructions of the phase-averaged wake velocity measurements reveal 2S shedding along the span of a stationary cylinder and hybrid shedding for the two vibrating cylinder cases, with planar wake topology transitioning from 2S to P+S to 2S for U ∗ = 5.48 , and 2S to P+S for 7.08. The observed wake topologies show significant deviation from predictions based on the Morse and Williamson (J Fluids Struct 25(4):697–712, 2009 ) shedding map. Vortex identification and strength quantification are used to provide insight into vortex dynamics and to propose a model of the dislocations. Examination of the time averaged wake characteristics shows the formation length, wake half-width, and maximum velocity deficit exhibit distinct spanwise trends aligning with the regions associated with specific shedding regimes.