Motions of floating power plant in regular waves

The purpose of this study is to develop a numerical prediction method which simulates motions of Floating Power Plant due to waves in shallow basin surrounded with breakwaters and seawalls. In this report, the 2-dimensional motions of a rectangular floating body moored by linear springs in regular waves were investigated. In these simulation models which were derived from the Dividing Region Method and the Boundary Elemental Method based on the potential theory, effects of reflected waves from a seawall were considered. The results of simulation were compared with those of 1/100 scale model test and the validity of these methods was indicated. The movements of a full size plant in waves were evaluated by the present simulation methods. Then following were concluded, 1) It was clarified that the simulation method based on the potential theory which did not include viscous resistance force, overestimated the movements and the force near natural periods of floating body's motions. 2) When the width and length of the floating body were much larger than the water depth, the simulated natural period of the rolling was different from the experimental one. However, it could be settled by modifying the added mass coefficient obtained theoretically. 3) The movements of a plant increased near the natural periods of motions and oscillations between a floating body and a seawall. In the perfect reflected waves from a seawall, the movements were 1.5 ∼ 2.0 times as much as those without reflected waves. (author)