Tetsuro Ikebuchi

An anti-motion device for a very large floating structure

We proposed a simple anti-motion device, which is a box-shaped body attached to an edge of VLFS. The performance of this device is investigated theoretically and experimentally in the present work. The theory is based on the eigen-function expansion method and the extension of this method to the oblique sea case is presented. The experiment is carried out in a wave tank with small-scale models. Both experimental results and the theoretical results show that the anti-motion performance of this device is very good at the design period in the case of beam-sea. The theory also demonstrates that this device reduces not only the deformation but also the shearing force and the moment of the platform and it also works well in the oblique sea.

Slamming load on a very large floating structure with shallow draft

The objective of this paper is to estimate the slamming load acting on a pontoon-type very large floating structure with a shallow draft. Experiments were carried out using elastic models with different rigidities in regular waves. The results revealed that the slamming load was strongly influenced by the rigidity of the model. The conditions under which slamming occurs depended on the extent of the bottom emergence and the velocity of the relative wave height at the bow of the model. These results were related to a simple procedure for estimating slamming load.

A newly developed wave monitoring system on ocean platform

A new wave monitoring system was developed to meet a need for measuring waves accurately and continuously for long period in ocean. This paper describes the newly developed wave monitoring system which is able to monitor not only frequency spectra but also directional spectra. The results of the model experiments are shown, which was carried out in order to confirm the validity of the system. It is demonstrated that the accuracy of the wave measurement is fairly good. One of the measured wave data, which were obtained when a big typhoon hit Okinawa in September of 2002 is presented.