Modeling of Flow Around FPSO Hull Sections Subject to Roll Motions: Effects of Nonlinear Boundary Conditions

The paper presents the development of BEM (Boundary Element Method) and FVM (Finite Volume Method) based models for the analysis of the flow around 2-D FPSO hull-sections fitted with bilge keels and subject to forced roll motions. Through these models an attempt is made to gain an insight into the two important aspects of the flow: separation around bilge keels and the effect of the free-surface. The effect of the free-surface and the resulting wave-body interaction is studied using a 2-D BEM model coupled with a Mixed-Eulerian-Lagrangian (MEL) time marching scheme for the free-surface boundary conditions. The separation around the bilge keels and viscous aspects of the flow are studied using a FVM based 2-D Navier Stokes (2DNS) solver with linear free-surface boundary conditions. The primary aim of the BEM model is to investigate the effects of the linear and nonlinear boundary conditions on the predicted flow within the scope of the parameters of the FVM model.