Nonlinear Radiation Problems for a Surface_piercing Body

Abstract

Chairperson: Robert F. Beck&&A Desingularized Eulerian-_Lagrangian Time_-domain Approach (DELTA method) is used to investigate fully nonlinear radiation problems of surface_piercing bodies. At each time step, a boundary-value problem is solved by placing fundamental singularities outside the computational domain and satisfying the boundary conditions at prescribed collocation points. This desingularization allows the use of simple isolated sources while retaining the necessary accuracy. &&A large outer region is investigated to postpone the free surface mean shift and wave reflection from the truncation boundary. The outer region is divided into exponential increasing panel sizes. The length, the first panel size and the panel number are found to be the crucial factors determining the effectiveness of the outer region. The effectiveness is relatively unaffected by forcing frequency and motion amplitude.