Research On Bow Slamming Problem Based On Fully Nonlinear Boundary Element Method

Ships often encounter slamming on flare areas or green water slamming on decks when navigating in high sea conditions,which threaten the reliability of the ship’s local structures and increase the fatigue of the hull components.Therefore,it is necessary to pay attention to this problem.In this paper,a method for calculating bow slamming and deck slamming problem based on the fully nonlinear boundary element method(FNL)is studied and verified.Besides,the slamming pressure characteristics are studied by this method.In this paper,the fully nonlinear boundary element method based on potential flow theory is used to simulate the motion of a 10000 TEU container ship in waves,and a program based on 2.5D Poisson equation is written to improve the orthogonality of the grid.The shape function method is used to obtain the pressure values of pressure measuring points on the instantaneously changing wet surface mesh.The FNL results of the slamming pressure and motion are compared with the experimental results of Shanghai Jiaotong University,and the effectiveness of the method is verified.Furthermore,FNL is used to study the characteristics of slamming,including the spatial distribution characteristics of bow pressure at different moments,the relationships of ship-wave relative motion during slamming moments,and the characteristics of slamming pressure at different pressure measuring points.This paper also analyzes the influence of slamming components on the section load of container ships.In addition,this paper takes the tumblehome hull as the research object,adopts the fully nonlinear boundary element method to simulate the motion of the tumblehome hull in waves,and compares the motion,pressure and deck-fluid position with the results of linear frequency domain potential flow method(BASIC).Besides,this paper also studies the influence of speed and the bow shape on deck slamming,the proportion of the deck slamming pressure load,etc.