Time-domain prediction of nonlinear motions and loads of body in large waves using a high order panel method

To predict the motions and wave loads for ships and floating structures under extreme sea-state, a fully nonlinear time-domain computation program base on the Mixed Eulerian-Lagrangian method with high-order boundary element approach is developed and the validity of computational system is analyzed. The standard Runge-Kutta method and the fourth order Adams-Bashforth-Moulton method are used for the time step method. The NURBS based high order BEM method is used to calculate the velocity potential at each time step. An artificial damping layer is adopted as the far field radiation condition on the free surface to avoid the wave reflection from the outer boundary, and the present method is found to be numerically stable. The pressure on body can be obtained by solving a boundary integral equation of time derivative of velocity potential. All of the numerical results in this paper agree well with experiment results and other calculated results.