Numerical Simulation Of Moored Floating Crane Ship Motion And Model Test Comparation Study

With China's offshore oil development, the floating crane ship plays an increasingly important role in the ocean engineering.Correctly calculate the wave induced motion of moored floating crane ship is the basis of the related work.This thesis introduces the different theorey of slow drift motion caculation in two software AQWA and MOSES.Carried on a numerical simulation of moored floating crane ship,and do a comparation between the scale ratio of 1:50 model test value andnumerical results,the results show that: Heave motion calculations result is reliable.Pitch and surge calculation is larger compared with experimental value for no viscous damping is considered. Max line tension value is 15% bigger .From engineering perspective, numerical results are conservative. Moored crane motion and tension response is very sensitive to significant wave height.When the water depth is 46m, draft/water depth ratio is 0.134, final results of Newman approximation and full-QTF method do not differ significantly.Numerical simulations underestimated mooring crane heave and pitch low frequency motion.This LF response is first order motion which induced by the actual low-frequency waves, the phenomenon should be respected.Proposed a easy method to estimate the surge viscous drift damping based on the results of calm water surge decay test,the results is good.Analysis of the depth of the impact of second-order slow drift load,the results show that: For floating crane ship, when the draft/water ratio is larger than 0.267, compared with full-QTF method, Newman approximation results underestimated the second-order slow drift load; when the draft/water ratio is smalller than 0.160, the full QTF matrix method and Newman approximation almost make no difference.Through the analysis of this thesis, giving some recommendations for using MOSES analyse moored ship.