Hydrodynamics of a floating liquid-tank barge adjacent to fixed structure in beam waves

Abstract

Physical experiments are conducted in a wave flume to investigate the hydrodynamic behavior of a liquid-tank barge floating near an identical barge. The two barges are arranged side-by-side and subjected to the action of beam waves. The floating barge is equipped with two liquid tanks and encounters the waves before the second barge. Systematic investigations on the effects of liquid tanks, mooring constraints, and arrangement configurations provide rich findings on the physics of fluids. Mathematical solutions are also derived to interpret the underlying mechanism behind the experimental observations. Our primary findings suggest two essential modes, i.e., trend and oscillatory components, in the motion of the floating barge. Of these, the oscillatory component can be strongly coupled with the liquid sloshing in the tanks. A mean-drift load caused by internal sloshing waves occurs as a result of the second-order nonlinearity, which significantly modulates the mean-drift force induced by external water waves and may change the drift direction of the floating barge. The properties of the mooring constraints effectively determine the trend component. Regardless of the liquid filling level in the tanks, the maximum ratio of the sloshing-wave height to the oscillatory amplitude of the barge always occurs at the fundamental natural sloshing period. The contributions of radiation damping and viscous damping to the barge oscillation are explicitly distinguished. The physical insights revealed in this study will help guarantee the operational safety of side-by-side floating structures.