LNG Tank Sloshing And Bow Slamming Study With The SPH Method Under GPU Architecture

With the growing consumption of liquefied natural gas (LNG), the number ofLNG carriers is rapidly increasing, and the capacity of LNG tanks is also expanding.When LNG carrier is sailing, it will suffer from the concentration local stress fromseawater, which threatening the safety of the hull structure. In addition, the LNGstorage tank sloshing pressure caused by the voyage itself and the seawater slammingmay damage the structure. So continuous monitoring and dynamic analysis of LNGcarriers which suffered from the tank sloshing pressures and the vessel shell slammingpressure is needed to prevent breakdown of the carriers.Concentrating on the newly emerged issues of the LNG transport ship, this paperconducted both physical model experiments and numerical model experiments.Numerical model experiments was carried out with SPH method, which can solve theproblem of fluid particle penetration and the stress field instability problem by thenew type of boundary condition approach. GPU computing was also involved toimprove the efficiency of the numerical simulation SPH method. In order to study thefactors of the LNG sloshing amplitude during the tank’s simple harmonic motion, aseries of different conditions of physical model experiments were designed andcarried out. The experimental results show that the pressure on the tank side wall is ina bimodal state during the simple harmonic motion. When the tank sloshing frequencyis close to the natural frequency of the tanker the LNG sloshing amplitude becomeslarger. And the physical model results also played a role of verifying the numericalsimulation results. Comparion between the simulation results of the tanker’shorizontally simple harmonic motion alone and results from the combination effectsshows that the induced force on the side wall becomes the biggest when the tankmovement frequency of shaking or sloshing is the natural frequency, and inducedforce on the side wall becomes the smallest when movement frequency of shaking andsloshing are same and the combination phase is zero. Finally, two-dimensional andthree-dimensional numerical simulation experiments were conducted both on theseawater slamming problem and tank sloshing problem. Results of fluid state atdifferent moments about the free surface, internal pressure distribution, internalvelocity distribution was obtained. The pressure duration curve of the solid side wallsunder the fluid impact was also obtained.