Suppression of vortex shedding of circular cylinder in shallow water by a splitter plate

摘要

The flow behavior around a vertical circular cylinder placed in shallow water was controlled by a splitter plate inserted at various locations downstream of the cylinder. The splitter plate has a fixed length which is equal to the diameter of the cylinder, D = 50 mm. The effect of plate thickness, T, was examined using three plates with different thicknesses, T/D = 0.016, 0.04 and 0.08. The gap between the base of the cylinder and the leading edge of the splitter plate was increased successively from 0 to 100 mm with 12.5 mm increments. Particle Image Velocimetry (PIV) was used to measure the instantaneous velocity vector field in the wake region at Reynolds number Re = 5000 based on the cylinder diameter. The mean velocity vector field, corresponding vorticity field and streamline topology and turbulence statistics were obtained using 200 instantaneous images. The water height was kept constant at 25 mm during the experiments. The splitter plate has a substantial effect on the suppression of the vortex shedding for the gap ratio (G/D) between 0 and 1.75D. For G/D = 1.75, the normalized Reynolds stress has a peak value of 0.0158, which is approximately 8,5 times smaller than the concentrations occurring for the bare cylinder. When the splitter plate was located at 2D location, no effect of the plate was observed.