Experimental investigations of turbulent flow characteristics around different cylindrical objects using PIV measurements

Turbulent flow features around three different objects of cylindrical shapes were investigated under identical flow conditions, using particle image velocimetry (PIV). Experiments were carried out for three in-line circular cylindrical objects (TCC), an oblong cylindrical object (OC), and a rectangular cylindrical object (RC) placed individually in the laboratory flume. The variations of turbulent parameters such as turbulent intensities, turbulent kinetic energy and Reynolds shear stress are presented on the symmetric plane along the object. Further, the contributions of burst–sweep cycles to the Reynolds shear stress and vorticity in terms of Q- criterion are also analyzed. Vorticity and turbulent intensity were found to be significantly higher within the gaps of TCC than observed in other objects. When compared with the sharp edges of RC, it is observed that the smooth edges of OC reduced turbulent intensities and Reynolds shear stress by almost half. The ejection and sweep events for RC are much more dominant than those of the other two objects along the longitudinal plane.