Investigation of passive flow control behind a circular cylinder with computational fluid dynamics

External flows acting on a blunt object cause eddies behind the object in the flow area, displaying irregular and time-varying flow behavior. Flow irregularities behind blunt objects such as circular cylinders occur in both laminar and turbulent flow situations. It is necessary to develop a control method to control and reduce the effects of these flow irregularities. The main purpose of the developed and used flow control is to reduce the effects of drag, lift, pressure and time-varying forces caused by the flow on the surfaces it comes into contact with, and to limit the negative conditions on the object. In this study, controlling the effects of two-dimensional time-dependent flow with airfoils placed symmetrically around the circular cylinder and limiting the force effects are examined. Analyzes were made using k-epsilon flow conditions. In CFD analysis, time dependent Reynolds mean Navier-Stokes equations (URANS) in laminar flow were solved and k-epsilon turbulence model was used as turbulence model. As a result of CFD analysis, time-averaged drag coefficient, lift coefficient and variations were obtained. In the analysis of the 2 models created, the Reynolds number was taken as 100 and kept constant throughout the study. As a result of the data obtained, the effects of the passive flow control method were observed. As a result of the study, the turbulent drag force obtained for the lean cylinder, which was 1,328, increased up to the value of 2,07 with the addition of the symmetrical wings in our study, but a significant decrease was obtained from the value of the turbulent lift force from 0,227. When the vorticity and velocity lines figures obtained after these examinations were examined, it was determined that the vortices occurring behind the cylinder were farther from the cylinder in systems where symmetrical blades were added.