EXPERIMENTAL INVESTIGATION OF FLOW STRUCTURE DOWNSTREAM OF PERMEABLE CYLINDERS

Authors : Bengi Şanli, Hüseyin Akıllı

Pages : 54-59

Doi:10.31127/tuje.349532

View : 28 | Download : 8

Publication Date : 2018-05-15

Article Type : Research

Abstract :Flow structure downstream of permeable cylinders was investigated using high-image density Particle Image Velocimetry technique in deep water. The free stream velocity is U ∞ = 156 mm/s, which corresponds to the Reynolds number of Re=6250 based on the cylinder diameter D=37.5 mm. To reveal the effect of the porosity, four different porosities (β= 0.4, 0.5, 0.6 and 0.7) were used. This study showed that the usage of permeable cylinder decreases the occurrence of large-scale vortical structures downstream of the bluff body. As the porosity increases, turbulent kinetic energy, Reynolds shear stress and intensity of turbulences decrease as a sign of attenuated fluctuations in the wake region. For the permeable cylinders having the porosity higher than 0.6, the flow behaves as there is no object in flow. 
Keywords : PIV, vortex shedding, permeable cylinder, Deep Water