Effects of upstream sharp edge square and diamond cylinders on the FIV of a circular cylinder. (May 2018)

• Record Type: Journal Article
• Authors: Tamimi, V.; Naeeni, S.T.O.; Zeinoddini, M.; Bakhtiari, A.
• Is Part Of: Marine structures. Volume 59(2018)
• Page Start: 237
• Page End: 250
• Publication Date: 2018-05
• Subjects: Flow induced vibrations -- Wake induced vibrations -- Square cylinder -- Diamond cylinder -- Tandem arrangement; Naval architecture -- Periodicals; Offshore structures -- Periodicals; Architecture navale -- Périodiques; Structures offshore -- Périodiques; Naval architecture; Offshore structures; Periodicals; 620.4162
• DOI: 10.1016/j.marstruc.2017.12.012
• Languages: English
• ISSNs: 0951-8339

Abstract

Abstract: This study deals with the flow induced vibrations of a freely vibrating circular cylinder in tandem arrangement with sharp edge square and diamond upstream cylinders. Spacing ratios of 4, 8 and 11 are examined. The lateral displacements, lift forces and the pressure data in the wake of the oscillating cylinder are recorded and analyzed. The single degree of freedom vibrating system has a low mass-damping parameter and the Reynolds number ranges from 1.5 × 10 3 to 3.7 × 10 4 . The overall transverse response of a circular cylinder in the wake of a sharp edge cylinder look like a VIV type of response. The ever increasing type of transverse oscillations for tandem circular cylinders at low spacing ratios no longer exists. It is concluded that in general, the wake from the upstream sharp edge cylinder has mitigated (around 40%) the lift force coefficient on the downstream cylinder. The oscillations and pressure frequencies occur primarily at the upstream sharp edge cylinder shedding frequency. It appears that the upstream wake is much stronger than the vortices past the downstream cylinder, so they take control of the downstream circular cylinder oscillations and shedding. Highlights: Experimental study of an oscillating circular cylinder at the wake of a fixed square and diamond cylinder. The circular cylinder at the wake of a sharp edge cylinder generally displays a VIV type of response. The wake from the upstream sharp edge cylinder has mitigated the lift force on the downstream cylinder. The oscillations and pressure frequencies occur primarily at the upstream sharp edge cylinder shedding frequency.