  We numerically investigate the effect of entrance condition on the spatial
and temporal evolution of multiple three-dimensional vortex pairs and wall
shear stress distribution in a curved artery model. We perform this study using
a Newtonian blood-analog fluid subjected to a pulsatile flow with two inflow
conditions. The first flow condition is fully developed while the second
condition is undeveloped (i.e. uniform). We discuss the connection along the
axial direction between regions of organized vorticity observed at various
cross-sections of the model and compare results between the different entrance
conditions. We model a human artery with a simple, rigid $180^\circ$ curved
pipe with circular cross-section and constant curvature, neglecting effects of
taper, torsion and elasticity. Numerical results are computed from a
discontinuous high-order spectral element flow solver. The flow rate used in
this study is physiological. We observe differences in secondary flow patterns,
especially during the deceleration phase of the physiological waveform where
multiple vortical structures of both Dean-type and Lyne-type coexist. We
highlight the effect of the entrance condition on the formation of these
structures and subsequent appearance of abnormal inner wall shear stresses - a
potentially significant correlation since cardiovascular disease is known to
progress along the inner wall of curved arteries under varying degrees of flow
development.
