T. Shipkowitz et al., Numerical study on the effect of secondary flow in the human aorta on local shear stresses in abdominal aortic branches, J BIOMECHAN, 33(6), 2000, pp. 717-728
Flow in the aortic arch is characterized primarily by the presence of a str
ong secondary flow superimposed over the axial flow, skewed axial velocity
profiles and diastolic flow reversals. A significant amount of helical flow
has also been observed in the descending aorta of humans and in models. In
this study a computational model of the abdominal aorta complete with two
sets of outflow arteries was adapted for three-dimensional steady flow simu
lations. The flow through the model was predicted using the Navier-Stokes e
quations to study the effect that a rotational component of flow has on the
general flow dynamics in this vascular segment. The helical velocity profi
le introduced at the inlet was developed from magnetic resonance velocity m
appings taken from a plane transaxial to the aortic arch. Results showed th
at flow division ratios increased in the first set of branches and decrease
d in the second set with the addition of rotational flow. Shear stress vari
ed in magnitude with the addition of rotational flow, but the shear stress
distribution did not change. No regions of flow separation were observed in
the iliac arteries for either case. Helical flow may have a stabilizing ef
fect on the flow patterns in branches in general, as evidenced by the decre
ased difference in shear stress between the inner and outer walls in the il
iac arteries. (C) 2000 Elsevier Science Ltd. All rights reserved.