The Floating Production, Storage and Offloading (FPSO) vessels in harsh environment are often vulnerable to green water. Green water is the unbroken waves which overtop the bow, side or stern part of the deck of the floating offshore structure. It occurs when the relative motion between the vessel and the wave exceeds the freeboard. Green-water occurrence could lead to deck flooding and damage to deck-mounted equipment. It is therefore necessary to consider the vulnerability of the floating vessel to green water in the design stage. The objective of this research is to determine the optimal principal dimensions of FPSO vessel necessary to prevent or mitigate the effects of green water even in extreme wave environmental conditions. In order to achieve this, the effects of extreme environmental loads on the vessel have been evaluated in terms of the maximum responses in heave and pitch modes of motion. Furthermore, an interactive programme, the ProGreen has been designed to optimise the principal particulars based on the response and freeboard exceedance analyses for the required storage capacity of the FPSO. This design technique helps to prevent or reduce the green water occurrence, ensures good performance during operation and increases the level of safety and operability of the vessel even in extreme wave conditions.
Department of Naval Architecture, Ocean and Marine Engineering, University of Strathclyde, Glasgow, United Kingdom
The development of floating offshore structures have been successfully and rapidly in many years. Many researchers has studied the dynamic behavior of of moored floating production storage and offloading structure. This paper investigated the dynamic behavior of catenary anchor leg moored twin hulls floating production storage and offloading which subjected to sea waves, in order to get insight knowledge on its dynamic behaviours due to various turret locations with different loading conditions. The comparison of the dynamics behaviour to the FPSO and it mooring lines are important when choosing potential development and optimal options. The research founded that it currently no information is available for the comparison of the dynamic behaviour of the internal turret moored of twin hulls FPSO at different loading conditions with various turret locations under the action of wave.
Department of Aeronautics, Automotive and Ocean Engineering,Mechanical Engineering, Universiti Teknologi Malaysia, Malaysia
Ocean and Aerospace Engineering Research Institute, Indonesia
This study compares the performance of a bearing with surface waviness liner to a plain bearing. Both bearings are functioned with palm oil as lubricant so that the potential advantages of the journal bearings could be identified. CFD analysis is developed to predict the numerical data for full film lubrication condition. A bearing of 60 mm in diameter with its ratio of length to diameter is 0.5, a clearance 250µm, and 200µm of wave amplitude is simulated. Semi circular wavy surface produces better results in term of load capacity than the plain journal bearing for a small eccentricity. The load carrying capacity is influenced by the increasing in speed of the shaft and the eccentricity ratio.
Teknik Mesin - Universitas Riau, Kampus Bina Widya Panam 28293 Pekanbaru, Riau Indonesia.
Faculty of Mechanical Engineering of Universiti Teknologi Malaysia , 81310, Skudai, Johor, Malaysia.
Oil-water two-phase flow in 0.0254m horizontal pipe is simulated using FLUENT 6.2. The stratified flow regime is modeled using Volume of Fluid (VOF) with turbulent model RNG k-ε. Grid independent study has been conducted to decide mesh size for solution accuracy and optimum computational cost. The simulation is performed in time-dependent simulation where oil and water are initially separated by patching the region base on difference in density. Observation on the effect of velocity to the pressure gradient was also simulated. Flow velocity at 0.2, 0.5, 0.8 and 1.1 m/s with same volume fraction for each phase with appropriate multiphase model and turbulence model are presented.
Department of Aeronautics, Automotive and Ocean Engineering, Universiti Teknologi Malaysia, Malaysia.
Ocean and Aerospace Research Institute, Pekanbaru, Indonesia.
