Numerical investigation of flow around a pipeline with a spoiler near a rigid bed

Abstract

Interaction of current with circular cylinders near a rigid bed is significant in the design of offshore structures, such as pipelines. Pipelines are buried to the seabed to be protected from damages caused by hydrodynamic forces or human activities. The pipeline laid on movable bed can be buried due to local scouring. A vertical plate on pipeline, called spoiler, has been developed to increase the rate and extend of scouring. In this study, the two-dimensional turbulent flow around a smooth pipeline with a spoiler was investigated at Re D = 9500 near the bed. The governing equations for the current problem were solved using ANSYS® 11.0-Flotran program package based on finite element method. The performance of the standard k–ε, standard k–ω, and shear stress transport turbulence models were examined on five computational meshes with different densities. The results obtained were compared with the published experimental measurements in literature. Present results showed that the attachment of a spoiler caused a large separation area in both upstream and downstream of the pipeline. The attachment of spoiler on top of the pipe increased the drag and decreased the lift force on pipe. Moreover, the spoiler causes non-zero downward lift. It is concluded that the k–ω turbulence model on the finest mesh is found relatively better in simulation of the flow field.