Wall shear stress and flow stability in a model fusiform aneurysm

Abstract

Levels of wall shear stress in arterial blood flow are known to con- tribute to the integrity of wall tissue, and are believed to have a bear- ing on the pathogenesis of aneurysm disease. The flow of fluid through a model aneurysm was computed using a spectral element algorithm to study the distribution of wall shear stress and the stability of the flow to non-axisymmetric perturbations. Substantially higher mean and fluctuating wall shear stress components were found in the distal (downstream) region of the aneurysm bulge when compared to recent experimental measurements. A global stability analysis demonstrates that flow conditions consistent with a human aorta will produce non- axisymmetric flow in an aneurysm consistent with that modeled here. These results demonstrate the necessity for detailed numerical modleling of these flows to accurately resolve the near wall fluid stresses