Prediction of coupled in-line and cross-flow vortex-induced vibrations of fluid-transporting free-spanning submarine pipelines: an integral transform solution

The Generalised Integral Transform Technique (GITT) was adopted to predict the dynamic behaviours of fluid-transporting free-spanning submarine pipelines, considering both the in-line and cross-flow vibrations. The coupled in-line and cross-flow fluid-structural system was analytically solved by GITT, where wake oscillator models were used to simulate in-line and cross-flow forces acting on the pipeline. The mathematical model and the solution method were validated against experimental results. The convergence behaviour of the solution method was analyzed, parametric studies were conducted, and the influence of internal fluid and external velocities were evaluated. Findings in this paper also demonstrated that GITT, which is a semi-analytical solution, is faster than finite element methods, hence highly suitable for conducting parametric studies for submarine pipelines.