Abstract: The hydrodynamic interaction between ship and bridge pier varies with the speed of navigation, which result in the changes of force and center of gravity of ship during navigation. In this paper, the laws of force, bowing moment, and center of gravity of ship varying with navigation speed are analyzed via physical model test together with mathematical simulation. Results reveal that the extreme values of transverse swaying force and bowing moment of ship increase correspondingly with the increase of navigation speed. In the presence of higher navigation speed, the ship would be transversely closer to bridge pier when ship head is near the tail vortex zone around pier; while the tail of ship would more easily hit the pier transversely when ship tail is near the vortex zone, and the ship would be more off-course transversely away from pier in its subsequent navigation. The research result would offer reference for future research on navigation safety and safe distance between pier and ship.

Key words: flow around pier, numerical simulation, bowing moment, center of gravity, UDF (user-defined function)