The viscous flow problem of roll damping of a FPSO is investigated by means of numerical solution of the unsteady two-dimensional Navier-Stokes equations. The finite volume method using unstructured grid is used to solve the integral form of the governing equations. The cross section of the FPSO hull with an initial roll displacement is left free to oscillate in roll, heave and sway in an initially still fluid. The numerical simulation provides a realistic picture of the physics of the phenomenon, capturing the vortex formation around the bilge keel. The numerical results are compared with experimental data showing a fairly good qualitative and quantitative agreement of the motion damping.

The highly viscous flow problem of roll damping of a FPSO is investigated by means of numerical solution of the unsteady two-dimensional Navier-Stokes equations. The finite volume method using non-structured grid is used to solve the integral form of the governing equations. The cross section of the FPSO hull with an initial roll displacement is let free to oscillate in roll in an initially still fluid. The numerical simulation provides a realistic picture of the physics of the phenomenon, capturing the vortex formation around the bilge keel. Numerical results from roll free decay tests are compared with experimental data showing a fairly good qualitative and quantitative agreement of the roll damping.

The paper discusses alternatives to represent the MLD (Mooring Line Damping) in models tests with truncated mooring lines. The work has performed both numerical experiments and reduced model tests. The results for stiffness and damping have been compared. This allows further considerations for future designs.

The purpose of the study is suggest a methodology to be applied in ocean platforms and ships in order to appraise the maximum impact pressure due to the slamming occurrence in the hull shape near its bottom or horizontal regions. This methodology uses a theory based on potential flow. However, there are some phenomena such as creation of a compressible air pocket between the body and free surface at the impact moment that requires a more complete theory and or experimental methods. This gives rise to experimental coefficients to reduce the theoretical errors. The procedure presented here goes by the platform motion dynamics and “impact topology” to allow the potential to be used. Due to the complexity of the phenomenon studied and need for certifying accuracy and precision of the results, tank tests at the LabOceano model basin were carried out. The results showed a good fitting between numerical results and experiments. It should also be pointed out that the pressure sensor used in these experiments gives a pressure distribution over the instrumented area what brings more reliability on the results and a better visibility to the slamming phenomenon. Lastly the methodology in this work stands out as an important tool to evaluate slamming loads.

The novel ‘Gimbal Joint Riser’ (GJR) device is an invention that allows for a free-hanging riser catenary configuration by providing the functionality of adding a ‘hinge’ or articulation in midway of the riser column. Such mid-length articulation allows that dynamic bending and compression at touchdown zone (TDZ) be reduced enough to get within acceptable design limits, what is not achievable with a traditional steel catenary riser (SCR) connected to a spread-moored FPSO in ultra-deep-water scenarios like Santos Basin in Brazil. The aim of the invention is to offer an economic competitive option to current state-of-the-art solution of applying Steel Lazy Wave Risers (SLWR), by eliminating the need of relatively expensive buoyancy modules. The objective of this paper is to present this new concept and simulations results.