Numerical analysis of added resistance on blunt ships with different bow shapes in short waves

In this paper, a Cartesian-grid method is applied to investigate the added resistance of KRISO's very large crude oil carrier hull with a different bow, particularly in short incident waves. The wavelength is fixed as half of the ship length in all computations. In the present numerical method, a first-order fractional-step method is applied to the velocity-pressure coupling in the fluid domain, and the volume-of-fluid method is adopted to capture the fluid interface. The ship is embedded in a Cartesian grid, and the volume fraction of the ship inside the grid is calculated to identify the different phases in each grid. The sensitivity of the time window during post-processing as well as the number of solution grids is investigated. The computed added resistance is compared with experimental data. In addition, the characteristics of the surge force for different wave amplitudes are observed by comparing the wave elevation around the bow. Further, to compare the relative magnitude of higher harmonic components with respect to the magnitude of the first harmonic component, harmonic analyses of the time history of the surge force are performed. Based on the present numerical results, the effects of the wave amplitude and bow shape on added resistance for a short wavelength are observed. Finally, the distribution characteristics of time-averaged added pressure on the ship surface are investigated for each bow shape and wave amplitude.