Numerical Simulation of Roll 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.