Experimental and numerical study of coupling effects between vessel motion and pipeline tension in deepwater J-laying

Abstract

During deepwater J-lay operations, the J-lay vessel and pipeline together form a coupled system. The dynamic responses of this system, including the vessel motion and pipeline tension caused by environmental loads, inevitably exhibit coupling effects. This paper describes the results of experimental and numerical studies conducted to investigate the effects of vessel–pipeline coupling on the global dynamic responses of J-lay vessels and pipelines under irregular wave conditions based on practical engineering. Large-scale full-depth experiments of the complete system are conducted in a 10-m-deep wave basin. The similarity of both the submerged unit weight and pipeline stiffness is considered in the design of the pipeline model. Numerical simulations are performed to further investigate the coupling effects on the dynamic characteristics of vessel motion and pipeline tension, and to analyze the coupling effects of J-lay operations in greater water depths. The results reveal that the coupling effects between the J-lay vessel and the pipeline are nonnegligible for both the vessel motion and pipeline tension responses in J-lay operations. The influence of these coupling effects is strongly related to the operation depth and pipeline properties. Overall, this study provides a reference for the design of J-lay systems and the development of J-lay simulation models.