Numerical Study On Hydrodynamic Interaction Of Multiple Floating Bodies Based On Two-way Potential Viscous Coupling Method

With the advancement of human exploration and continuous development of ocean resources,various floating structures are widely used in ocean engineering.There are often small slender gaps between these floats relative to their own size.Relevant studies have shown that when the incident wave frequency is close to the natural frequency inside the gap,strong resonance phenomenon occurs between the fluids in the gap.This phenomenon is generally called "gap resonance".When gap resonance occurs,the fluid height between the gaps will increase sharply,which will also sharply increase the wave force on the structure,leading to a significant increase in the motion response of the floating structure under wave action.Finally,it poses a great threat to the stability,safety,and operational efficiency of floating structures.Traditional physical experiments,analytical and potential flow methods,and CFD methods all have accuracy or efficiency defects to varying degrees when studying gap resonance.In order to thoroughly understand and recognize the characteristics of gap fluid resonance under different conditions,this paper will use a newly proposed efficient bidirectional potential viscous flow coupling numerical method to study and analyze the problem.This paper uses an Open FOAM numerical solver based on the two-way potential viscous flow coupling method to study the gap resonance phenomenon between floating bodies arranged side by side under different conditions.It conducts research on different gap widths,float drafts,and float bottom corner radii,analyzes the change rules of gap resonance frequency,resonance amplitude,and wave load response characteristics with frequency,and carries out harmonic analysis of the results,revealing the dependence relationship between resonance frequency and these parameters.Firstly,the two-way potential viscous flow coupling algorithm is used to establish a numerical tank to verify the accuracy and efficiency of the algorithm,and then simulation of numerical wave generation and wave absorption is carried out.The results show that under the premise of ensuring accuracy,the two-way coupling algorithm can achieve better wave generation and wave absorption effects and has significantly improved efficiency compared with traditional CFD algorithms.Then,using the constructed numerical tank,the influence of different gap widths,float drafts,and float bottom corner radii on the hydrodynamic interference between floating bodies under regular waves is analyzed.For the gap resonance of fixed floats arranged side by side,the vertical wave force on the float and the horizontal wave force on the upstream float deviate significantly from the fluid’s resonance frequency,and their change rules are different under different influencing factors.At the same time,the differences in wave height between different positions can reflect the reflection of waves under different conditions,and the various components of different physical quantities are also different under different conditions.Finally,utilizing the fast calculation feature of the two-way potential viscous flow coupling algorithm,further simulation analysis of the hydrodynamic resonance phenomenon of irregular waves under parallel arrangement of double boxes is carried out.The study found that the waves in the gap are concentrated near the natural frequency of the double-box system,and the response of wave height in the gap under the action of irregular waves changing with frequency is more sensitive than under the action of regular waves.