NONLINEAR WAVE LOADING USING SIGMA-TRANSFORMED AND UNSTRUCTURED FINITE ELEMENT MESHING

This paper describes a finite element numerical scheme for modelling the wave-induced loading on a horizontal cylinder. A numerical wave tank is utilised with a σ-transformation applied to regions upwave and downwave of the cylinder in order to take advantage of the mapping between free surface and bed. The region around the cylinder is discretised using a Voronoi mesh, with free surface tracking achieved using the Wu and Eatock Taylor (1994) scheme. In this case, the free surface velocities are determined using an accurate higher order interpolation scheme. A combination of the Sommerfeld radiation condition and a damping zone is used to eliminate end effects at the far radiation boundary. Results are presented for sloshing free surface motions in a rectangular tank, progressive waves with and without an immersed horizontal cylinder. Promising agreement is achieved with the analytical and experimental force data of Ogilvie (1963) and Chaplin (1984)