Control of vortex shedding from a circular cylinder surrounded by eight rotating wake-control cylinders at Re=100

Author(s)

Assi, G. R. S. ; Orselli, R. M. ; Silva-Ortega, M.

• Document type: Journal article
• Source: JOURNAL OF FLUIDS AND STRUCTURES; v. 89, p. 12-pg., 2019-08-01.

Abstract

The present work investigates the suppression of vortex shedding of a circular cylinder of diameter D surrounded by a polar array 8 rotating wake-control cylinders of a considerably smaller diameter d/D = 0.05. A numerical approach was employed to simulate the laminar flow at a Reynolds number of 100. The governing equations were discretised by the finite volume method for a two-dimensional computational domain. The main varying parameter was the rotation speed of the control cylinders, measured as a fraction of the incoming flow speed. A controlled wake (one without alternating vortices) was achieved when the tangential velocity at the surface of the control cylinders was greater than 3 times the free stream velocity. A significant reduction of the overall drag coefficient and mitigation of the unsteady hydrodynamic forces acting on the system were observed as rotation was increased. Given enough rotation, a negative mean drag (thrust) was achieved. The power spent to rotate the 8 control cylinders appeared to be higher than the power-loss associated with the mean drag of a bare cylinder. While still working with an active, open-loop control system, this investigation supports the development of a closed-loop wake-control device for offshore applications. (C) 2019 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 14/50279-4 - Brasil Research Centre for Gas Innovation
• Grantee: Julio Romano Meneghini
• Support Opportunities: 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 Opportunities: Regular Research Grants