Aneurysm blood pulse flow is a crucial cardiovascular medicine topic that affects patient health and therapy. Aneurysms, localized blood vessel bulges or balloonings, interrupt blood flow and create complex fluid dynamics. Blood flows through aneurysms in unusual patterns, including vortices and stagnation, which can increase wall shear stress and thrombus formation. Pulsatile blood flow exacerbates these consequences by cyclically stressing the fragile artery wall. The reference paper entitled “ Hemodynamic Changes Quantified in Abdominal Aortic Aneurysms with Increasing Exercise Intensity Using MR Exercise Imaging and Image-Based Computational Fluid Dynamics” led the current CFD study.

Figure 1: Schematic of Aneurysm geometry model from reference paper

Simulation Process

The geometry model is constructed based on MRA images, shown in Figure 2. Fluent Meshing is the powerful tool for producing a meticulous grid regarding fewer cells while keeping quality high. 646747 polyhedra cells are the result. Although the blood regime remains laminar through the veins and Aneurysm, it benefits from a pulsing flow. Thus, a User-defined Function (UDF) is written particularly for the project to apply pulse flow inside the Aneurysm.

Figure 2: The constructed Aneurysm geometry model

Post-processing

The modeling results illuminate aneurysm blood pulse flow, notably wall shear stress. Contour shows skin friction coefficient, which affects wall shear stress. Skin friction is stronger around the neck and some areas of the aneurysm sacs (green to red). Localized increased wall shear stress may cause aneurysm growth or rupture. Supporting our findings, other contours reveal complicated flow patterns and higher velocities (red and yellow regions) in the main vessel and aneurysm necks. Wall shear stress increases in high-velocity zones. Aneurysm sacs have blue zones of reduced velocity, indicating flow stagnation or recirculation. Over time, this heterogeneous wall shear stress distribution with high and low stress may undermine the vessel wall. Complicated flow patterns highlight aneurysm hemodynamics, which can increase cyclic stress on weakening artery walls. These findings emphasize the importance of wall shear stress distributions in aneurysm risk assessment and treatment planning.