Numerical simulation of a large-scale riser with vortex-induced vibration

Abstract

ANSYS multi-physics software was applied to a Fluid-Structure Interaction (FSI) task, a large-scale riser with vortex-induced vibration (VIV) undergoing shear inflow environment. The purpose of this paper is to evaluate the performance of the FSI software and to provide the model test some supplementary information, such as the hydrodynamic visualizations of vortex wake and some dynamic characters of the pipe. Basic frequency analysis has been done first to make sure that the ANSYS FSI solution strategy is competent to give a reliable simulation to this pipe system, and then the RMS value of instantaneous amplitude and vortex shedding visualization under different input velocities are provided. Visualization of the vortex wake indicates a hybrid mode of vortex shedding along the pipe in those simulation cases. In this paper, an instantaneous amplitude definition is introduced to give a reasonable conception of RMS for instantaneous amplitude of multi-model VIV. Copyright ？ 2008 by The International Society of Offshore and Polar Engineers.