Roll damping decay of a FPSO with bilge keel

• Numerical simulation of the roll damping decay of a FPSO section.
• The agreement between the numerical solution and the experimental data is remarkable.
• The results demonstrate the importance of the correct consideration of the bilge radius.
• Vortex shedding at the bilge keel and damping coefficient saturation were captured.
• Results confirm the increase of damping coefficient with the height of the bilge keel.

The roll damping decay is investigated for a Floating Production Storage and Offloading (FPSO). For this purpose, a roll decay test of a middle section of FPSO with bilge keel is simulated by means of the numerical solution of the incompressible two-dimensional Navier–Stokes equations. The governing equations are solved using the finite volume method and the upwind Total Variation Diminishing (TVD) scheme of Roe–Sweby. The upwind TVD scheme resolves and captures the physics of the fluid dynamics without spurious oscillations in regions of the flow field with strong pressure gradients. The numerical results are compared with experimental data for validating the numerical scheme implemented. The simulations indicated the strong influence of the bilge radius in the damping coefficient of the FPSO section. Interesting results were obtained regarding the time series of the displacement of the body and vortex shedding around the bilge keel.