Vortex shedding control of circular cylinder by perforated shroud in deep water

¹ Cukuruova University, Mechanical Engineering Department, 01330 Adana, Turkey
² Cukuruova University, Ceyhan Mechanical Engineering Department, 01950 Adana, Turkey
³ Osmaniye Korkut Ata University, Energy Systems Department, 80000 Osmaniye, Turkey

^* Corresponding author: tdurhasan@cu.edu.tr

Published online: 12 May 2017

Abstract

The aim of the present study is to control the vortex shedding downstream of a circular cylinder (inner cylinder) by the existence of outer perforated cylinder concentrically located around the inner cylinder in deep water. The flow characteristics downstream of concentrically placed coupled cylinders were investigated quantitatively by the Particle Image Velocimetry (PIV) technique. Diameter of the outer perforated cylinder and inner cylinder were kept constant as D_o=100 mm and D_i=50 mm. The depth-averaged free-stream velocity was also kept constant as U=100 mm/s which corresponded to the Reynolds number of Re_Do=10,000 based on the outer cylinder diameter. Experiments were conducted for six porosities (β = 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8) in order to show the effect of these parameters on the flow control. Maximum values of both Reynolds shear stress, <uv> and turbulence kinetic energy, <TKE> significantly decreased with the existence of outer perforated cylinder and also, the location of peak magnitudes of turbulence statistics occurred at locations further downstream compared to the bare cylinder case. The most effective control was revealed for the porosity of β=0.7.