Hydrodynamic performance and wave dynamics in the moonpool of a ship. Part II: Geometry effects on resistance reduction and wave suppression

In the part I, through the study of the KCS model with the moonpool, it was observed that the internal flow field, especially the front section, differs significantly from the traditional well-type moonpool, with differences in resistance oscillation and wave oscillation frequency compared to the results calculated by empirical formulas. To further explore the impact of hull form parameters on the hydrodynamic performance and wave dynamics of the moonpool at high Froude number, nine parameterized modification schemes based on chamfer, slot, and fillet were designed for the bottom portion of the hull in front of the moonpool. Numerical simulations were performed using the interFoam solver in the OpenFOAM, employing the PIMPLE algorithm and the SST k-ω turbulence model. The results show that the effect of different modification schemes on the vessel resistance varies significantly, with changes ranging from −7.3 % to 14.5 %. Among these, the chamfer leads to a reduction in resistance, and the slot results in a significant increase in resistance. Furthermore, all modifications effectively suppress wave, with the maximum suppression reaching over 50 %, that the specific suppression effect is related to the height and length of the modified region. The changes in resistance and wave are attributed to differences in the flow field inside the front section of moonpool for each scheme, and it is noted that these two factors are not directly correlated. • Investigated the influence of front-end geometry modifications on hydrodynamics of a KCS model with a moonpool. • Demonstrated the chamfer, slot, and fillet at moonpool entrance can visibly affect resistance and internal wave behavior. • Found that reduction in resistance is not directly correlated with wave suppression performance across different geometry. • Revealed variations in internal flow field structures among different geometry schemes, driven by distinct vortex dynamics. • Identified chamfer schemes as effective in both wave suppression and resistance reduction, but sensitive to dimensions.