Experimental And Numerical Study Of Hydrodynamic Responses Of Side-by-side Floating Bodies Under Wave Action

In order to exploit,storage and transport the oceanic resources of oil and gas,kinds of large floating structures and vessels are used in marine engineering operations.It is important to note that,there will be a narrow gap between the two side-by-side floating structures or vessels,which is very hard to avoid.Then,under the action of certain frequencies of incident wave,the fluid in narrow gap may come into a significant resonance.The appearance of wave resonance in gap can lead blast to floating structures and vessels.Moreover it will improve the hull shaking,reducing the operation efficiency of ocean engineering.It also has a harmful effect on horizontal and vertical wave force,making a serious damage on the stabling of hulls and the safety of structures.In the actual ocean engineering,different structures have different breadths.So,their capacity of confront the influencing of wave resonance is different.Optimizing the breadth of structures or even changing the layout direction of structures relative to incident wave play an important role in reducing wave resonance in narrow gap.For this reason,it has both theoretical and practical significance to research the effect of breadth of structures of wave resonance in narrow gap.In this thesis,a simulation of adjacent double floating structure by two rectangular tanks with 2D physics model and potential flow model was conducted.Firstly,we proceeded physical model experiments in 2D wave flume,studied the influence of breadth of tanks to the phenomenon of wave resonance.Secondly,we verified and had an expansion to the experiment results by linear potential numerical model and viscous flow model.In this paper,we set lab experimentations with different total breadth and breadth ratio of the rectangular tanks,observe the wave heights in the narrow gap between two floating bodies with the incident frequency and time history.We did research in the influence of breadth of wave resonant frequency,phase difference,reflection coefficient,transmission coefficient and energy dissipation in narrow gap.Then we calibrate the damping term with experimental results,and compared of experimental results and numerical results have verified the reliable of damping term.Then,by this modified method we calculated out the horizontal and vertical wave force on floating bodies.By using viscous flow model,we drill down into the effect of breadth ratio of the two rectangular tanks to the horizontal and vertical wave force on them.At the end of the paper,an in-depth discussion have been carried out by conventional potential model and viscous flow model,verified that the breadth of the rectangular tank and narrow gap had an effect on wave resonant frequencies of both piston mode and sloshing modes.And the draft has an effect on wave resonant frequencies too.