CFD Simulation of Vortex-induced Vibration of Free-standing Hybrid Riser

Abstract

This thesis presents a 3D numerical simulation for a Free Standing Hybrid Riser under Vortex Induced Vibration, with prescribed motion on the top to replace the motion of the buoyancy can. The model is calculated using a fully implicit discretization scheme. The flow field around the riser is computed by solving the Navier-Stokes equations numerically. The fluid domain is discretized using the Chimera grid approach. Grid points in near-wall regions of riser are of high resolution, while far field flow is in relatively coarse grid. Fluid-structure interaction is accomplished by communication between fluid solver and riser motion solver.

Simulation is based on previous experimental data. Two cases are studied with different current speeds, where the motion of the buoyancy can is approximated to a ‘banana’ shape. A fully three-dimensional CFD approach for VIV simulation for a top side moving Riser has been presented.