Experiment of falling cylinder through the water column

Hydrodynamic features of a falling cylinder into the water column are investigated experimentally. The experiment consisted of dropping three cylinders of various lengths into a pool where the trajectories were filmed from two angles. The controlled parameters are cylinder's physical parameters (length to diameter ratio, center of mass location), and initial drop conditions (initial velocity, and drop angle). Six trajectory patterns (straight, spiral, flip, flat, seesaw, combination) are detected during the experiment. The center of mass position has the largest influence on the trajectory of cylinders. The observed motion of cylinders is well simulated using a numerical model based on the momentum and moment of momentum balances using triple coordinate transform.