Flow dynamics and wall shear-stress variation in a fusiform aneurysm

Pulsatile flow through a tube featuring a sinusoidal bulge is computed in order to determine the flow dynamics and wall shear-stress conditions encountered under conditions representative of blood flow through a human abdominal aortic aneurysm. A high-order spectral-element algorithm is employed to accurately determine velocity and vorticity fields, plus wall shear stresses, which are notoriously difficult to measure experimentally. A greater level of detail in the flow is revealed when compared to recent particle image velocimetry experiments. For both the mean and standard deviation of wall shear stress, minimum levels are found at the widest point of the aneurysm bulge, and maximum levels are recorded in the distal (downstream) region of the bulge. In an aneurysm with length and maximum diameter 2.9 and 1.9 times the artery diameter, respectively, peak instantaneous wall shear stress is 2.4 times greater than the peak wall shear stress recorded in a healthy vessel.