Prediction of Behaviors of Floating Artificial Islands.

点击翻译按钮获取中文摘要

Confidence to its safety and reliability for many years must be very high if we are to realize the idea of floating artificial islands. In this perspective the objectives of our research were: 1.Improvement of confidence to the prediction of extreme values of wave heights at a given location in very long return period. 2. Development of the prediction technique of wave forces on large scale floating structures located at shallow water close t o the coast. 3. Evaluation of safety of a floating structure system composed of a lot of elements including the station keeping facilities. Results of the research were: 1. We collected wave data obtained Genkai-nada area and predicted 1 00 years waves with taking into account the idea of confidence limits. The amount of data accumulated is not sufficient to have the reliable results in this area.2. (1) A theoretical method was developed for predicting wave forces on a floating structure supported by a lot of elementary floating bodies. In this me … More thod the effects of non-uniform depth of water and the existence of the coast are appropriately considered. Its theoretical basis is a perturbation and a matched asymptotic deduced from the difference between the structure's size and the size of each element composing it; the former is of th e order of kilometers comparable to the scale of non-uniform depth while to the latter's scale the sea bottom is flat. (2) A theoretical method to calculate second order wave forces, drift forces, on a structure composed of a lot of circular cylinders was given and the characteristics of these forces were understood.3. (1) A computer simulation of the behaviors in the water of long flexible structures, which would be used as elements of the stationkeeping facility of the structure, was studied and it was found that their nonlinearity have to be considered carefully when designing the safe facility. (2) We almost completed a computer program to simulate the behaviors of the artificial floating island system including various factors such as the station keeping facilities and to demonstrate their computer graphics. Less