Numerical Investigation Of Solitary Wave-induced Slamming On Flexible Structure By MPS-FEM Coupled Method

With the constant exploitation of ocean resources,the safety of offshore and coastal structures has been an object of concern to the engineers.The wave-induced slamming is one of most common research issues in the field of naval architecture and ocean engineering.Slamming is the phenomenon of structure impacting the water surface.It is commonly observed on the bow and stern of ship,offshore platform,trestle bridge and very large floating structure(VLFS).The extremely high load during the slamming would bring large deformation or damage to the structures,and bring impairs to the safety of these structures.Therefore,the slamming force analysis is an indispensable procedure in the design and manufacture of the offshore structures.In present paper,the in-house fluid-structure interaction(FSI)solver – MPSFEM-SJTU is employed to simulate the interaction between solitary waves and the flexible structure.The effects of structural flexibility,as well as the wave amplitude,freeboard and structure position,on the wave-induced slamming force are primarily investigated.This paper contains the following contents:The numerical wave tank is first implemented in the context of MPSFEM-SJTU solver to generate the solitary waves with various amplitudes.The profile of the obtained numerical wave is subsequently compared with the theoretical solution.The satisfactory agreement achieved in the comparison indicates that desired solitary wave can be generated using the present solver.It also lays firm foundtion to the simulations of the wave-plate interaction in the following sections.Then the problem of 2D green water slamming is simulated.In the simulations of the slamming on the rigid structure,the effects of freeboard on the slamming load are analyzed.The regions on the plate that most vulnerable to the slamming load are also presented.Then the solitary wave impacting onto the flexible structure is simulated.By comparing the obtained results with the counterparts in the rigid cases,the effects of structural flexibility are investigated in the aspects of free surface,slamming pressure and velocity field.Finally the problem of wave-induced slamming on the structure bottom is investigated.In the study of 2D solitary wave interacting with the horizontal rigid plate,the effects of wave amplitude and plate elevation(or clearance)on the slamming load are primarily considered.By comparing the obtained results with the available experimental data,the accuracy of the present solver with regard to slamming problem is verified.Then the solitary waves impacting onto a horizontal fleixble plate is simulated.The effects of structural flexibility on the slamming force are quantified through the comparison of maximum slamming force between the rigid and flexible cases.It is found that the structural flexibility alters the peak value of the vertical force and distribution of the slamming pressure evidently owing to the vibration of the plate.The simulations are subsequently extended to 3D cases.The effects of the structural flexibility on the slamming process are analyzed in the aspects of green water on deck,maximum uplift force,slamming pressure distribution and velocity field.Apart from the parametric studies on wave amplitude and plate elevation,the 3D effects during the wave-plate interaction are discussed.