CFD-beam theory time-frequency-domain hybrid method for pipeline flow-induced vibrations

This study presents an efficient computational fluid dynamics (CFD)-Beam theory time-frequency-domain hybrid method (TFDHM) to predict pipeline flow-induced vibrations (FIV). CFD is used to simulate the time-domain fluctuating pressure of the pipeline fluid, and the finite element method (FEM) based on Euler–Bernoulli beam theory is used to rapidly predict the frequency-domain vibration of the pipeline structure. A fluid load mapping method (FLMM) is introduced to convert the time-domain pressure into frequency-domain excitation load for application to a beam model. A curved pipeline FIV is simulated by the TFDHM. The results are compared with those calculated by the full-time-domain three-dimensional fluid-structure interaction method. It is found that the TFDHM is significantly more efficient than the FTDM, with a computation time of only 45 s versus 23 h 47 min for the FTDM. Furthermore, the influence of key factors on the TFDHM results is analyzed to optimize the FLMM. The accuracy of the numerical results is verified using the experimental results of the curved pipeline. In contrast, the TFDHM results have higher predictive reliability than those of FTDM under actual boundary constraints, which is because the former can use the measured frequency-domain dynamic stiffness of the pipeline support. Therefore, the TFDHM achieves computational accuracy equivalent to that of conventional methods while providing markedly improved computational efficiency and engineering applicability.