Experimental investigation of flow-induced vibration interference between two circular cylinders

Experimental study of flow around two grooved cylinders arranged in tandem

“…They were able to suppress time-averaged drag, fluctuating drag and fluctuating lift of the upstream cylinder by 70%, 65% and 89%, respectively, for any spacing between the cylinders, and also find significant reduction in fluid forces on the downstream cylinder. Many investigations of tandem configurations by Brika and Laneville [8], Laneville and Brika [9], Hover and Triantafyllou [10] and Assi et al [11] showed substantial complexity in fluid dynamics as the spacing between the cylinders is varied, including a combination of vortex induced vibration and gallopinglike oscillations. When the upstream cylinder is fixed and the downstream cylinder is free to oscillate, both vortex resonance and the occurrence of wake-galloping instability are equally possible and can occur separately or combined depending on the separation distance according to Bokaian and Geoola [12].…”

Vortex-induced Vibration of a Flexible Free-hanging Circular Cantilever

“…More recently, some experimental studies on a low mass ratio freely vibrating cylinder were performed, but the conditions were only for 1-directional motion and within relatively low Reynolds numbers (1,500 < Re < 21,000). Additionally, the bottom-end of the cylinder was conditioned by a tiny gap to the tank floor, in order to obtain a 2-dimensional effect of the flow [13][14][15].…”

Optimal energy harvesting from vortex-induced and transverse galloping vibrations

“…The Reynolds number range of all of the cases are similar. In particular, the Reynolds number at the amplitude's curve peak was for Khalak and Williamson (1999) Re ≈ 5000, Assi et al (2006) Re ≈ 5500, Klamo (2007) Re ≈ 2600 and Re ≈ 3200 for the present VIV test.…”

“…The test section is made of glass which allows the flow to be viewed from either side, as well as from the bottom, allowing to perform flow visualizations through PIV measurements. A circular cylinder (B), made of aluminium, of 25 mm of diameter D and immersed length L of 430 mm, was attached through a bearing (C) to the shaft of a servomotor (D) fixed to the free end of a doubleblade elastic system, following the arrangement introduced in Assi et al (2006). The elastic system was made up of with two parallel rigid aluminium blocks (E), coupled to a pair of thin spring-steel flexor blades (F).…”

“…With regard to the end conditions, no attached end-plate was used (effects of end conditions are reviewed in Morse et al, 2008), which leads to a less distinctive upper/lower transition (similar to those from Klamo (2007), Assi et al, 2006). The decision to not use end-plate was in order to avoid undesired effects when rotating the cylinder where small misalignments lead to big damping effects when the cylinder is rotated.…”