Flow structure behind tandem cylinders in shallow water flow

In this study, the flow characteristics of two tandem cylinders having different spacing was investigated experimentally by Particle Image Velocimetry (PIV) technique. In all experiments, two Plexiglas cylinders having the diameter of D=50 mm were used and the distance between cylinders was changed between G=0mm and 225mm. All experiments were carried out in 25 mm water height. The value of Reynolds number based on the cylinder diameter was Re=5000. Time-averaged flow characteristics such as velocity vector field, corresponding vorticity contours, streamline topology and Reynolds stress concentrations were obtained from averaging 300 images which were acquired at 15 Hz frequency.Flow characteristics downstream of the cylinders do not affect from each other after the gap ratio of G/D=3.0