Influence of Vessel Wall Motion and Phase Angle Between Pressure and Flow Waves on Wall Shear Stress Distribution in a Compliant Aortic Bifurcation Model

The present study investigated the effect of the phase angle between pressure and flow waves on the wall shear stress distribution in an aortic bifurcation model with flexible walls. An elastic model representing the typical geometry of the human abdominal aortic bifurcation was made and the photochromic flow visualization technique, which is effective for wall shear measurements with moving walls, was employed in the in vitro experiments. The results of the wall shear stress distribution in our flexible model are relevant to our understanding of the role of fluid mechanics in atherosclerosis of arterial bifurcations. The wall shear stress distributions along the outer wall (low shear stress zone) were similar for three different phase angle conditions (+12°, −17°, and −61°; negative value means flow leading pressure wave). A significant decrease in the maximum wall shear stress was noted on the inner wall (high shear stress zone) for the phase angle of −17° compared to the other phase angles.