Control of flow structure in the wake region of circular cylinder with meshy wire in deep water

Abstract

In this study the aim is decreasing the effect and the intensity of the temporary loads resulted from vortex shedding that have an impact on the cylinder (chimneys, high buildings etc.) located in deep water and the object or objects in the wake region and definition of the optimum values (wire thickness and porosity β) With different thickness and different porosity ratios the effect of meshy wire that surrounded a circular cylinder of D=50 mm diameter was observed at Re_D=5000. The porosity ratios were four different values between a range of β=0.5-0.8 with an interval of 0.1. The thicknesses of wire were 1 mm, 2 mm, 3 mm and 4 mm. The flow structure in the wake region of circular cylinder was tried to be controlled by meshy wire that surrounded the cylinder. Experiments were carried out by using particle image velocimetry (PIV) technique. Comparing with bare cylinder results, turbulence kinetic energy (TKE) and Reynolds shear stress values increase with wire thicknesses of b=1 mm, 2 mm for all porosity ratios and decrease with b=3 mm, 4 mm. With porosity ratio of β=0.6 and wire thickness of b=4 mm TKE and Reynolds shear stress results show that meshy wire controls the flow in the wake region of the cylinder. Frequency value results also define that best flow control is obtained with β=0.6 and b=4 mm.