The steady increase of demand in global container traffic leads to increase the size and capacity of container carriers with large bow flare. Due to large flare, container carriers experience more non-linear ship motions and wave induced load which is termed as slamming in actual seas. RaNS based motion simulator developed at The University of Tokyo, which has the capability of handling 6(six) degrees of freedom (DOF) is used in analysis. Numerical method is validated for a modern container ship model named KCS in regular head waves and mechanism of slamming on the bow flare region is analyzed based on visualization of flow field i.e. velocity contour, surface vector below the free surface etc. near the bow flare region. Present numerical method predicts ship motions accurately and phenomena of slamming can be described by visualization technique.
Slamming can be classified based on the region of the hull surface where it occurs as bottom slamming, green water loading, breaking water impact and bow flare slamming. Among these kinds of slamming, evaluation of hydrodynamic loading due to bow-flare slamming is still a challenging task. Traditionally, strength requirements in the bow flare region are evaluated based on the empirical formula proposed by various classification societies. Study reveals that there is a sizeable difference occurs in evaluated strength requirements by using classification society's empirical formula. Therefore, a direct calculation method is needed for evaluating the strength in the flare region in the design stage of hull surface. Inviscid potential-flow based numerical methods are used widely for evaluating wave resistance because of its' robustness and less computational time requirements. However, flow separation, generation of vortex and non-linear wake filed are occurred in real conditions, which is due to viscous effects. Therefore, improvement is necessary in numerical calculation methods.
