2.1.5. Mesh Independence Study

In order to avoid the grid resolution errors, three different mesh models are generated in the fluid domain. The number of cells generated is two, four, and eight hundred thousand, respectively. The number of prism layers is set to four for capturing the near-wall velocity profile. The simulations were performed for pulsatile velocity profile of a typical resting condition on the aneurysm region in thoracic aorta and the results presented are of a male person (age 61) in Figure 4. The velocity profile was obtained from the published literature [15].

Velocity profile graph [15].

The simulation is performed assuming Newtonian behaviour. The simulation is run for 6 cycles to allow the solver to stabilize and the results for the seventh cycle are plotted. Three points are monitored. Point 1 corresponds to inlet, point 2 corresponds to the location where the aneurysm is present, and point 3 refers to the outlet (Figure 5). Figures ​Figures66​6–8 present the velocity profile over time for various mesh counts. The negative value in the velocity is because the flow is considered to be positive in the upward direction in the inlet region. It can be seen from all the three figures that the mesh-independent solution is reached for a mesh count of 400,000. However, for ensuring fidelity, all further simulations are performed with a refined mesh having a mesh count of 800,000.

Velocity profile over time at monitoring point 1 (inlet) for various mesh counts.

Velocity profile over time at monitoring point 2 (aneurysm) for various mesh counts.

Velocity profile over time at monitoring point 3 (outlet) for various mesh counts.