The Experimental Investigation of the Motion Characteristics of Truncated Submerged Floating Body Under the Regular Wave Action

This paper presents the motion response of a truncated submerged floating body under the action of regular waves. A twin-circular model with different boundary conditions is tested in the experiment. In order to consider the effect of the boundary stiffness, one set of boundary device is designed to apply the restraint stiffnesses in the horizontal, vertical and torsional directions, respectively. The boundary stiffnesses of the truncated model are determined by using ANSYS through matching the motion responses of the truncated model and the full model. The experimental results show that the boundary stiffness has a significant impact on the dynamic behavior of the truncated model, as the natural frequency increases with an increase in boundary stiffness. The motion amplitudes of the model become larger when the wave frequency approaches the horizontal natural frequency. The study also reveals that mooring lines may go slack at high wave heights, leading to a lying figure-eight shape in the centroid trajectory of the model during the slack–taut process.