Análise computacional de interação fluido-estrutura aplicada em um spool

Abstract

The coherence method is presented, which is based on spectral analysis of temporal responses, obtained from computational simulations with fluid-structure interaction. This method is applied to the results of seven 2–D computational simulations of a mass-spring model’s fluid-structure interaction. Also, is presented an analysis of the results from fluid-structure interaction study of a spool, which is clamped next to the seabed and is subjected to a marine currents of 0.77 m/s. This analysis is accomplished from the results of a computational simulation. Another computational simulation is performed to estimate the submerged spool’s natural frequencies. Spool is a tubular marine structure used by oil and gas’ industries. In the context of tubular and marine structures in general, used by this industrial segment, the interest on VIV phenomenon arises. VIV presents a non linear inherently nature and affects strongly the oil and gas’ industries’ production fields proper working. The computational simulations were done with MFSim code, for both mass-spring system and spool. MFSim is a computational code, which is being developed by Fluid Mechanics Laboratory of Federal University of Uberlandia and has receiving Petrobras’ collaborations and contributions of the Mathematics and Statistics Institution of University of Sao Paulo. The application of coherence method required an algorithm, developed in MATLAB language, which is used at the MFSim simulations’ post-processing step. The great advantage of coherence method arises in the fact that with this method it’s possible to obtain conclusions about problems’ physics that other methods aren’t able to show clearly. Applying coherence method to the mass-spring model simulations, it was possible to show that fluid-structure interaction occurs strongly between the cylinder and the vortex wake, presenting coherence values about 0.8. For the another regions, it was possible to concluded that the fluid-structure interaction occurs weakly, presenting coherence values about 0.2. From spool simulations it was possible to concluded that the VIV in-line is greatest in structure’s center.