International Science and Technology Journal

Pipelines carrying fluids are primarily used in oil and gas industry. These pipelines may experience vibrations caused by high-pressure fluctuations in fluids, leading to a turbulent flow scheme. High vibration level poses a serious risk to the pipeline system, as it could cause pipes to vibrate intensely, severely impairing fatigue cracking. The interaction between the fluid and the structure leads to what is known as flow-induced vibrations (FIV). In this paper, a one-way FIV numerical analysis was conducted using ANSYS® Workbench, by modeling flow in elbows with different angles. Elbows are one of the critical parts along a pipeline, as they are mainly used to redirect fluid flow direction. The data regarding the pipe and the crude oil specifications are based on information received from Mellitah Oil and Gas Company. Stress, modal, and CFD analyses were carried out on elbows with three different angles. Two quite distinct flow velocities are considered, one representing the standard flow, and the other representing an extreme case of high flow velocity. Due to this extreme case, changes in modal parameters, in stress, and in deformations were observed along the pipes. This study emphasizes the importance of geometric features and the effect of sudden changes in fluid flow velocity on pipeline structures. ............... Keywords............... Flow induced vibration, pipelines, crude oil, static analysis, modal analysis.