Analysis of second-order wave force on floating bodies using FEM in time-domain

Abstract

Second-order wave effect on hydrodynamic forces acting on offshore structures is numerically investigated with focus on multi-body hydrodynamic interactions by using finite element method in time domain. Boundary value problems were formulated up to second order according to Stokes' perturbation expansion. Laplace equation with boundary conditions was solved by classical finite element method based on the weak formulation. Wave damping zone was employed to implement radiation condition numerically. The time integration of free surface condition was conducted by 4th order Adams-Bashforth-Moulton method. Hydrodynamic forces on bottom-mounted and truncated cylinders up to second-order were investigated as validation study. Second-order forces such as drift force and diffraction force on side-by-side arranged bodies were analyzed and compared with model test data. The agreement between present computations and other results was fairly good. ？ 2010 by The International Society of Offshore and Polar Engineers (ISOPE).