Topographical Effects on Wave Exciting Forces on Huge Floating Structure (2)

A new method is developed to predict wave drift force acting on a large floating platform set on a sloping beach. The platform is supported with a lot of floating element. We assume the structure's dimensions in the horizontal direction are comparable with the topographical scale, while each floating element's size is small.To predict drift force acts on such kind of platform, refraction, diffraction and wave breaking should be considered. Assuming the bottom slope is comparable small to wave slope, refraction is described by mild slope equation. It is matched with the solution that holds near the floating element. To consider energy absorption due to breaking, new solution is derived. It is composed of Bessel function and Whittaker function that is a kind of confluent hypergeometric function.Delaunay triangulation method is adopted for pre-process for FEM. This method generates moderated triangle mesh automatically.Drift force that acts floating body set on slope bottom has irregular resonance. It shows that topographical effect should be incorporated.