Interaction of In-Line and Cross-Flow Vortex Induced Vibrations in Risers

VIV in pipeline and risers has been studied through numerous experimental investigations using simplified model set-up, consisting of spring mounted rigid cylinders. Models have been constructed to allow in-line, cross-flow, or both in-line and cross-flow motions. Comparison of the model results shows overall agreement, although distinct differences exist between the individual model test series. Different explanation models have been established to try to improve the consistency, however, seldom definitive conclusions have been reached. The present paper presents the use of CFD to document the importance of the interaction of in-line and cross-flow motions on VIV response. 2D numerical tests have been performed using NS3 (DHI-CFD code) for a model undergoing in-line, cross-flow, combined in-line and cross-flow, and cross-flow in combination with forced in-line motions. The paper compares the results with some recent model tests and quantifies the significance of interaction.Copyright © 2002 by ASME