Laboratory-scale investigation of the Ventilated-Trousers device acting as a suppressor of vortex-induced vibrations

Author(s)

Cicolin, M. M. ; Assi, G. R. S.

• Document type: Journal article
• Source: OCEAN ENGINEERING; v. 142, p. 411-418, SEP 15 2017.
• Web of Science Citations: 0

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{*}zeta < 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. (AU)

• FAPESP's process: 14/50279-4 - Brasil Research Centre for Gas Innovation
• Grantee: Julio Romano Meneghini
• Support type: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 11/00205-6 - Investigation of new methods for suppressing flow-induced vibrations of offshore structures
• Grantee: Gustavo Roque da Silva Assi
• Support type: Regular Research Grants