Research on Behavior analysis of a Riser using CFD

Abstract

The riser for offshore oil production or drilling is a very long line like structure with a circular cross section. It is important to prevent collision of adjacent risers due to the vortex-induced vibration (VIV). In this study, the computer program code is developed for predicting the hydroelastic behaviors of the riser in current. The hydrodynamic force on a cross section of the riser is solved as two or three-dimensional flow by using the computational fluid dynamics to which the finite element method is applied. The employed FEM is based on a discretization of the spatial derivatives of the Navier-Stokes equation. Therefore, the hydrodynamic force in the transverse direction due to VIV can be considered in the prediction. The hydrodynamic forces on the several cross sections, which are divided for computing the structural response, are computed. And Moving Mesh is applied to the computer program code.We compare the calculation results and confirm effectiveness of the Moving mesh that Moving Mesh is effective in behavior presumption of Riser.