  We numerically investigate the influence of flow development on secondary
flow patterns and subsequent wall shear stress distributions in a curved artery
model, and we compute vascular metrics commonly used to assess variations in
blood flow characteristics as it applies to arterial disease. We model a human
artery with a simple, rigid 180-degree curved tube with circular cross-section
and constant curvature, neglecting effects of taper, torsion and elasticity.
High-fidelity numerical results are computed from an in-house discontinuous
spectral element flow solver. The flow rate used in this study is
physiological. 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 observe and discuss differences in secondary flow patterns that
emerge over the rapid acceleration and deceleration phases of the physiological
waveform, and we directly connect the variation in intensity of these secondary
flow patterns along the curvature to differences in the wall shear stress
metrics for each entrance condition. Results indicate that decreased axial
velocities under an undeveloped condition produce less intense secondary flow
that, in turn, reduces both the oscillatory and multidirectional nature of the
wall shear stress vector, and we link this effect to abnormalities in computed
stress metrics. These results suggest potentially lower prevalence of disease
in curvatures where entrance flow is rather undeveloped-a physiologically
relevant result to further understand the influence of blood flow development
on disease.
