Laboratory-scale investigation of the Ventilated-Trousers device acting as a suppressor of vortex-induced vibrations. (15th September 2017)

• Record Type: Journal Article
• Authors: Cicolin, M.M.; Assi, G.R.S.
• Is Part Of: Ocean engineering. Volume 142(2017)
• Page Start: 411
• Page End: 418
• Publication Date: 2017-09-15
• Subjects: Vortex-induced vibration -- Suppression -- Ventilated Trousers -- Circular cylinders; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2017.07.024
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: Experiments have been carried out with circular cylinders fitted with a suppressor of vortex-induced vibrations called the Ventilated Trousers (VT). Tests were performed at laboratory scale in a free-surface water channel with fixed and free-to-respond models in one degree of freedom. The oscillating tests were performed with elastically mounted cylinders with low mass and damping ( m * ζ < 0.009 ). Reynolds number varied from 5000 to 25000 and reduced velocity varied between 2 and 15. Tests with fixed models showed that the VT increased the mean drag and practically eliminated the fluctuating lift force when compared to a bare fixed cylinder. Free-response tests showed that the VT was able to reduce 60% of the peak amplitude of vibration, thus reducing the maximum drag compared with that of a bare oscillating cylinder. Three hypotheses are proposed to explain the physical mechanism underlying the suppression by the VT: local disruption of vortex shedding; three-dimensional disruption of the near wake; and the increase of hydrodynamic damping. Abstract : Highlights: VIV of a cylinder with VT was characterized through the synchronization range. VT suppressor reduced the VIV peak amplitude of displacement in 60%. VT suppressor increased drag in 25%. We propose three hypotheses to explain the physical mechanism.