The purpose of this study is to investigate the effect of Reynolds number and sweep angle on the blood flow patterns in S-shaped bends, resembling the femoral artery. The numerical simulations of steady flows in S-shaped bends with 45, 90, and 135 degree of sweep angles are performed at Reynolds numbers of 125, 500, and 960. The hemodynamic characteristics such as secondary flows, vorticity, and axial velocity profiles are analyzed. Flow patterns in S-shaped bends are strongly depend on both Reynolds number and sweep angles that can be categorized into three groups of low Reynolds numbers, high Reynolds numbers with low sweep angles, and finally high Reynolds numbers with high sweep angles. Moreover, an interesting flow feature observed in S-shaped bends is the secondary flow asymmetrical behavior at Reynolds number of 960 occurred around the second bend exit and along the outflow straight section. This symmetry-breaking phenomenon which has not been reported in the pervious studies is shown to be more pronounced in S-shaped bend of 90 degree sweep angle.

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