Experimental and numerical investigation on springing and whipping responses of a 21000TEU containership

In this study, the nonlinear hydroelastic behaviour in terms of ship motion and load responses of an ultra-large 21000 TEU containership in head regular waves are investigated experimentally by a segmented model equipped with a U-shaped backbone. In addition, numerical simulations by using CFD-FEM coupled method are also carried out to reproduce the hydroelastic responses for a comparative study. The ship hydroelasticity in head regular waves under various conditions of wave length, wave height and speed are comprehensively studied. Attention is mainly focused on the responses of springing and whipping phenomena. The springing responses under different orders of resonance frequency are systematically analyzed. The results indicates that for the ultra-large containership with relatively small bow flare area but large fat parallel middle body, the whipping loads contributes no much to the total loads even in high wave states. However, the springing loads can be several times large of the wave-frequency loads even in low and middle wave state, which makes the total loads to be very large and almost in a same magnitude as the whipping loads in severe waves.