The oil-water core annular flow through a U-bend is simulated by computational fluid dynamics based on the Eulerian model. More flow parameters and the effect of annulus thickness on core annular flow are discussed. Conformity between the simulated and experimental data is observed. The development of oil-water core annular flow in the U-bend is analyzed, and the distributions of pressure and velocity are discussed. Results of the Eulerian model and volume-of-fluid (VOF) model are compared and the influence of oil properties on total pressure gradient is investigated. The suitable range of annulus thickness is identified. The results provide suitable operation conditions for designing the U-bend pipefitting.