Kim, Kyung Sung (2014-05). Simulation of Multi-Layer-Liquid Sloshing Effects on Vessel Motions by Using Moving Particle Simulation. Doctoral Dissertation.
Thesis
The coupling and interactions between ship motions and inner-liquid tank sloshing have been investigated by a coupled program between ship motion and sloshing analysis programs. For the sloshing program, Moving Particle Simulation (MPS), which is based on the Lagrangian approach, is used. This sloshing program is validated through comparisons with corresponding experimental results both qualitatively and quantitatively. This validated MPS method has been extended to multi-liquid systems by adding newly adopted models which are buoyancy-correction, surface tension, and boundary conditions at interfaces. Each new model is validated either mathematically or theoretically for comparison. Moreover, a new tracing method of interface particles is suggested by modifying the conventional free-surface searching method in MPS for a single-liquid system. The newly developed MPS for multi-liquid system has been tested for three-liquid sloshing and the obtained results have been compared with the corresponding experimental results. The verified MPS system is coupled with a ship motion program to investigate the sloshing effects on vessel motions. The coupled program was applied to two sloshing tanks, partially filled with fresh water, on a barge-type FPSO. The simulation results were compared with experiments by MARIN and showed good agreement. The most noticeable coupling effects on vessel motions show that the peak frequencies are split and shifted, especially in roll motions. Furthermore, comparison between cases of liquid- and rigid-cargo showed the importance of sloshing effects more clearly. The developed program was also applied to the multi-liquid sloshing problem to consider the wash-tank. In the case of the multi-liquid-layer, there are more than one sloshing natural frequencies, so the relevant physics can be much more complicated compared to the case of a single-liquid-tank. The oscillations of the interfaces have different amplitudes and frequencies. Since the wash-tank contained multi-liquids, short waves at the interface were generated due to Kelvin-Helmholtz instability and the phenomenon was successfully reproduced by the developed MPS-simulation technique.
The coupling and interactions between ship motions and inner-liquid tank sloshing have been investigated by a coupled program between ship motion and sloshing analysis programs. For the sloshing program, Moving Particle Simulation (MPS), which is based on the Lagrangian approach, is used. This sloshing program is validated through comparisons with corresponding experimental results both qualitatively and quantitatively. This validated MPS method has been extended to multi-liquid systems by adding newly adopted models which are buoyancy-correction, surface tension, and boundary conditions at interfaces. Each new model is validated either mathematically or theoretically for comparison. Moreover, a new tracing method of interface particles is suggested by modifying the conventional free-surface searching method in MPS for a single-liquid system. The newly developed MPS for multi-liquid system has been tested for three-liquid sloshing and the obtained results have been compared with the corresponding experimental results. The verified MPS system is coupled with a ship motion program to investigate the sloshing effects on vessel motions. The coupled program was applied to two sloshing tanks, partially filled with fresh water, on a barge-type FPSO. The simulation results were compared with experiments by MARIN and showed good agreement. The most noticeable coupling effects on vessel motions show that the peak frequencies are split and shifted, especially in roll motions. Furthermore, comparison between cases of liquid- and rigid-cargo showed the importance of sloshing effects more clearly. The developed program was also applied to the multi-liquid sloshing problem to consider the wash-tank. In the case of the multi-liquid-layer, there are more than one sloshing natural frequencies, so the relevant physics can be much more complicated compared to the case of a single-liquid-tank. The oscillations of the interfaces have different amplitudes and frequencies. Since the wash-tank contained multi-liquids, short waves at the interface were generated due to Kelvin-Helmholtz instability and the phenomenon was successfully reproduced by the developed MPS-simulation technique.
