Hydroelastic Response Of Large Floating Structure In Nonlinear Waves

Due to the characteristics of short construction period,low cost and convenient maintenance,large floating structure have been widely used in the development of marine resources,and it become a research hotpot in the international marine engineering community.with the nonlinear interaction between the wave and VLFS in rough sea,elastic response of floating structure have obvious nonlinear features.In order to ensure the safety and stability of floating structure under extreme sea conditions,it is necessary to predict effectively the hydroelastic response of VLFS under nonlinear waves.(1)With the help of STAR-CCM+ calculation platform,a three-dimensional nonlinear wave viscous flow numerical tank is established.First of all,the fifth-order Stokes wave was generated based on the velocity inlet method,and the calculation accuracy is discussed on the grid division.Then,the combined wave focusing model,dynamic grid technology and user function are used to develop the software's program and generate the freak wave which can be focused at the specified time and position.(2)Based on the principle and method of CFD-FEM,a numerical model of the interaction between fifth-order Stokes and elastic floating structure is established in the three dimensional numerical wave tank,and the vertical deformed displacement of this plate are calculated.The effectiveness of the CFD-FEM coupling method is verified by comparing the vertical displacement results of experiment,three-dimensional plate theory and numerical simulation in various wave environments.Then,we studied the effects of the thickness,the amplitude of the incident wave and three-dimensional model.The conclusion shows that the increase of the amplitude of wave will aggravate the hydroelastic response of VLFS,and the vertical displacement at each point of the structure will rise with the increase of the amplitude;When the thickness of the floating body changes,the changes in vertical displacement at the free end of the floating body is small,and at the middle position,the thickness change has a greater influence on the hydroelastic response of the structure.(3)Using three-dimensional viscous numerical tank established,coupling numerical model between freak wave and floating,structure,then the hydroelastic response of the structure with freak wave is studied.The results show that as the height of the freak wave increases,the hydroelastic response of the floating plate intensifies.When the peak of the wave height is large,the wave will rise to the upper deck of VLFS and produce a nonlinear effect.Due to the energy concentration,the greater the amplitude of each wave component,the freak wave which have small wave spectrum width can make stronger the nonlinear interaction than other spectrum width.