Session: 06-05-02 Marine Hydrodynamics

Submission Number: 156357

Time Domain Coupling Numerical Investigation on Motion and Green Water Load of a Semi-Submersible Platform 

The ships sailing on the sea may suffer from various extreme sea conditions, which cause the hull to produce large nonlinear motion, resulting in the phenomenon of waves on the deck of the hull, deck equipment and superstructure, and may even lead to the loss of stability of the ship.

Present paper aims to develop a three dimensional time domain numerical method to investigate the hydrodynamic performance of the catamarans subjected to frequent water on deck and slamming with forward speed. As for present method, the Rankine source is adopted to accurately solve the velocity effect of floating body and instantaneous liquid level change of surface; meanwhile, the finite volume method is used to solve the local induced green-water loads and investigate the water on deck influence and nonlinear slamming. Within the coupling between the Rankine source method and the finite volume method, the local solver applies the initial and boundary conditions of the water phase height, velocity and ship motion obtained from the first one, then the green water problem can be solved by the finite volume method. The rigid motion equations include an addition green water loads to consider the influence of the water slamming.

In order to verify the accuracy of the numerical calculation, relevant experimental studies were carried out to investigate the effects of different wave conditions and forward speeds on the platform motion, water on deck and slamming. By comparing the numerical results with the experimental results, the water on deck loads and the motion responses of the fast platform shows a good agreement. The physical mechanism of current evolution and load distribution in water on deck problem are obtained by analyzing the experimental phenomenon and numerical results. A reasonable and effective method for predicting the impact load of waves on deck is also obtained.

Presenting Author: Rui Qin Shanghai Jiao Tong University

Presenting Author Biography: PhD candidate at Shanghai Jiao Tong University