SIMULATIONS OF CURRENT FORCES ON A PIPELINE IN FREE SPAN THROUGH THE COMPUTATIONAL FLUID DYNAMICS
Humberto Arakaki Junior1; Diener Volpin Ribeiro Fontoura2; José Roberto Nunhez1; Celso Kazuyuki Morooka1
1 UNICAMP; 2 DPR Engenharia
doi:10.20906/CPS/COB-2015-0188
Resumo
Subsea pipelines which present free span portions suffer actions from the sea current. It can result in Vortex Induced Vibration (VIV), which can damage and cause possible failure by several values for the fatigue processes. In this work, Computational Fluid Dynamics (CFD) is used to evaluate hydrodynamic current forces, in particular vortex shedding forces. Seabed effects are also investigated. A circular cross section for the pipeline with external diameter (D) is used to build two-dimensional numerical model. Simulations of the flow past the circular section nearby a plane wall are carried out for the Reynolds number around 20000. Drag and lift forces are evaluated. Gap (e) between the circular section and the wall were considered and results were tested with different turbulence models (SST and k-ε). An open source code (OpenFOAM®) and a free software (Salome) was used to create the geometry and mesh. Simulation results were compared with the literature. Results show that almost no effect from the wall is observed for e/D>1. For 1<e/D<0.5, even though vortex shedding still happen and wall effects were observed. Finally, for 0.3<e/D<0.1, vortex shedding is not observed. In general, the procedure here presented has shown good results for drag and lift forces.
Palavras-chave: CFD; Subsea pipeline; Free span; Circular cylinder; Vortex shedding