Numerical prediction of slamming on bow-flared section considering geometrical and kinematic asymmetry

Abstract

Asymmetric impacting phenomenon is quite common for the sailing ship when it encounters oblique waves. The asymmetrical water entry problem of a full scale bow-flared section from Ultra Large Container Ship (ULCS) was investigated using CFD method in commercial code FLUENT. A two-phase flow model was established based on N-S equations, which were discretized through the finite volume method and the free surface was captured by VOF model. The body motion was achieved in the dynamic mesh model with prescribed dynamic boundary condition. The impacting forces were obtained through direct numerical integration on the body surface. The validation and convergence were carried out through comparing experimental data and other numerical methods in already published literature. Two kinds of asymmetry, heel angle as geometrical asymmetry and horizontal velocity as the kinematic asymmetry, were comprehensively considered in numerical simulation and significant attention is given into the discussion of their effects on impacting hydrodynamics including pile-up water, pressure and slamming forces. The results show the geometrical asymmetry is important on these hydrodynamics if the flow separation does not happen. Otherwise, the kinematic asymmetry can significantly influence pile-up water form and further determines the pressure and slamming forces.