Numerical prediction of asymmetrical ship slamming loads based on a hybrid two-step method

Abstract

Slamming load is one of fundamental importance in the design of ship structures. However, the prediction of ship slamming load largely focuses on the head sea due to the more complex physics mechanism in oblique waves. In this paper, asymmetrical slamming loads of ship in oblique waves had been numerically predicted, where one hybrid two-step solution was applied through combining seakeeping theory and CFD method. Firstly, asymmetrical ship motions (vertical, horizontal and roll motions) were obtained through the seakeeping analysis. Then, slamming loads of two typical bow-flare sections were predicted through applying the CFD method, where the complicated flow forms (flow separation and air pocket) were included. The characteristics of impact hydrodynamics including free surface, pressure distribution and pressure time history were analyzed systematically showing that the slamming load in oblique wave has obvious asymmetry and is much larger than the head sea. These findings clarify the complicated impact phenomenon in oblique wave cases, which could improve our understanding on the asymmetrical impact of bow-flare sections.