Investigation of flow characteristics for different grooved shape and bare cylinder at different heights in shallow water

In this project, the control of the unsteady flow structure formed behind a cylinder placed horizontally in shallow water is investigated experimentally with the help of grooves having different geometries opened on the cylinder. For this purpose, the effects of the geometric parameters of the grooves and the different heights where the horizontal cylinder is placed in the water on the flow structure behind the horizontal cylinder are examined in detail with the help of particle imaging velocimetry (PIV) technique. The experiments are carried out at a constant Re number at different heights (hD) where the horizontal cylinder is placed in shallow water. With the help of PIV technique, instantaneous and average velocity vectors are measured in two dimensions at many points simultaneously in a planar flow area. With the help of the measured velocity vectors, instantaneous and average vortex and streamline values and turbulence (normal and Reynolds stresses) statistics in the flow area are obtained and the results obtained are analyzed with the help of TECPLOT program and detailed information about the flow is obtained. In CorelDRAW program, instantaneous velocity vectors and vortex contours are monitored and detailed information about flow structure is obtained. It is concluded that large negative counter at h: 37.5 mm is observed for bare cylinder, at h: 45 mm for square grooved cylinder and rectangular grooved cylinders. Also, no negative counter is observed at h: 0 mm due to the bottom effect. Two foci points and saddle point have been seen as they move away from the surface. When the wake regions consisting of two foci points are examined, the smallest vortex region is at h: 37.5mm rectangular grooved cylinder at a: 90o and 95o.