NUMERICAL OFFSHORE TANK: DEVELOPMENT OF NUMERICAL OFFSHORE TANK FOR ULTRA DEEP WATER OIL PRODUCTION SYSTEMS

摘要

There are several developments concerned to simulate the behavior of floating bodies under waves in the restricted boundary conditions so called numerical wave tank. The main feature of these tanks is to calculate full Navier-Stokes equations taking account the viscosity and free surface conditions. However, the dynamic behavior of oil floating exploitation units in actual ocean environmental condition, in waves, wind and current, is more complex and very difficult to simulate using full non-linear Navier Stokes equations. In addition, in the ultra-deep water, it is the primer importance to consider the more precise mooring line and riser's dynamics in the analysis. The present numerical simulator laboratory called Numerical Offshore Tank is a development that takes account almost all physical phenomena acting on the floating bodies and mooring and risers lines. Since full non-linear solution is not available, the several numerical, empirical and analytical models are being considered and integrated to numerical simulator. The time domain potential problem is solved to wave forces acting on the bodies and empirical models are used to simulate current and wind forces. To represent mooring & riser lines, the finite element model with more realistic hydrodynamic force models is used. Even the simulator is using the full hydrodynamic equation, the calculation time of the simulation for floating bodies with several risers & mooring lines is very high. Therefore, special cluster with 60 PC based computer was built running the code in the parallel processing. Since the preparation of all data set for numerical experiment is very tedious work, the special pre-processor PREA3D was developed for this purpose. This pre-processor allows the fast change of the environmental and system conditions to run several test conditions. Another important feature is the visualization of the results of the simulation tests. The entire 3D view of the system is presented in the Virtual Reality room with stereoscopic projection of the Numerical Tank Laboratory.