A MULTIPOLE ACCELERATED DESINGULARIZED METHOD FOR COMPUTING NONLINEAR-WAVE FORCES ON BODIES

Nonlinear wave farces on offshore structures are investigated. The flu id motion is computed using a Euler-Lagrange time-domain approach. Non linear free surface boundary conditions are stepped forward in time us ing an accurate and stable integration technique. The field equation w ith mixed boundary conditions that result at each time step are salved at N nodes using a desingularized boundary integral method with multi pole acceleration Multipole accelerated solutions require O(N) computa tional effort and computer storage, while conventional solvers require O(N-2) effort and storage for an iterative solution and O(N-3) effort for direct inversion of the influence matrix. These methods are appli ed to the three-dimensional problem of wave diffraction by a vertical cylinder.