불규칙파 중 K-FPSO의 측벽 그린워터 발생 특성에 관한 연구

Abstract

In this study, an experimental observation is suggested about sidewall green water problem on a FPSO in irregular waves. A series of model test has been performed for K-FPSO under oblique wave conditions. In the test, a model ship of 1/60 scale and 10 wave probes were utilized to directly measure the relative wave motions which indicates the occurrence of the sidewall green-water. Bow quartering waves of 150 degree heading were considered including 100-year return period wave conditions. Firstly, time series of the relative wave motions are analyzed to identify critical sidewall green-water events. Statistical values are compared to show the spatial characteristics of the relative wave motions along the sidewall. Then, the probability of exceedance for relative wave motions is compared between the experimental data and the linear diffraction calculation. In this case, the Rayleigh distribution based on the linear calculations may significantly under-predict the probability of exceedance of the relative wave motions above the freeboard. Thus, semi-empirical correction methods are studied to evaluate the extreme relation wave motions and the occurrence of green water events.