Study of wave drift forces affecting FPSO systems

Mean wave drift forces and moments are second order derivatives of wave amplitude and can be computed from quadratic products of first-order quantities.Their affects are the surge,sway and yaw caused by wave drift forces and moments for moored FPSO systems.To solve first order radiation and diffraction problems,a higher-order boundary element method(HOBEM) was applied and symmetry was considered to calculate the hydrodynamic interactions with FPSO systems.The second-order wave drift forces and moments affecting an FPSO were computed by the near-field method based on direct pressure integration.Compared to results obtained through the constant method,the current algorithm has higher accuracy and can converge steadily even for high frequency waves.