Abstract
3 dimensional vortex structure around free falling rectangular pillar was studied in comparison with circular cylinder. Both objects are close to square shape in front view but flow fields measured by PIV method were different. Vortex pair starting from the upper corner was stretched to upper direction in case of rectangular pillar, while it was observed at upper surface in case of circular cylinder. On the upper surface of rectangular pillar, water flows out in front view, while in side view water flows in.
