Wave-In-Deck Load on a Jacket Platform, CFD-Derived Pressures and Non-Linear Structural Response

The paper presents an industrial application of CFD and non-linear structural response codes in offshore technology. A Wave-In-Deck load due to an extreme wave, acting on a jacket platform, is studied numerically. Particular attention is given to details of local flow and local non-linear dynamical response of the structure. A very detailed FEM model of the platform deck structure, composed of shell elements, is embedded into a non body-conforming CFD grid of computational cells. The applied CFD code is a Navier-Stokes equation solver with an improved Volume of Fluid (iVOF) method employed to displace and re-construct fluid’s free surface and uses a simple, Cartesian grid. The two computational grids, FEM and CFD, are independent. The challenge of a direct mapping of CFD-derived fluid pressures onto structural FEM shell elements is addressed. Then the non-linear dynamical response of the structure is found in time domain. The employed CFD code is ComFLOW while the FEM part is handled by the well-known commercial program LS-DYNA. The composed approach utilizes both robustness of VOF-based methods in tracking of the fluid’s free surface and reliability of FEM structural codes such as LS-DYNA.Copyright © 2009 by ASME