CFD-FEM numerical simulation analysis of ship whipping response under extreme sea conditions
[Objective]This paper investigates the coupling effect of ship nonlinear wave load and transient high-amplitude slamming load in view of the whipping response of ships under extreme sea conditions.[Methods]A two-way computational fluid dynamics-finite element method(CFD-FEM)fluid-structure in-teraction method is used to carry out the numerical simulation of an S175 container ship,and the results are compared with the test results and 2D linear strip theory.The testing of a segmented ship model with a vari-able cross-section elastic backbone is carried out,and the analysis of the bow's slamming load and high-fre-quency nonlinear whipping characteristics is undertaken based on the two-way CFD-FEM fluid-structure inter-action method.The results are then verified through comparison with the model test.[Results]The influ-ence of wave slamming load on the whipping response of the bow cannot be ignored.The second order high-frequency component induced by whipping accounts for 59.86%of the low-frequency wave bending moment in sea state 6.[Conclusions]The proposed two-way CFD-FEM fluid-structure interaction method can cal-culate the whipping response accurately.The nonlinear wave-induced load and dynamic structural response of the ship under extreme sea conditions are affected by the transient slamming load of the bow.In conclusion,the high-frequency whipping response should be taken into consideration in the safety design and assessment stages of ship structures.