## 3 Results
### Numerical Modelling Augmentation
#### 3.7.1 Relevance of Modelling Certain Physiological Features
 & \(k-e\) & NC-Y & - &
\begin{tabular}{c} Small differences in WS were  
Assuming that wall motion is indeed relevant to the model, it becomes necessary to choose a wall constitutive model which requires the estimation of material properties. The assessment of these parameters is still a challenging objective to fulfill and, to date, there is still no \"gold standard\" methodology to perform this task. Thus, it becomes relevant to study the impact of considering populational averaged values. [PERSON] et al. (2018) developed CSM models with patient-specific geometries of AAA. The objective was to evaluate the numerical variations when patient-specific constitutive parameters are used instead of averaged values. The results evidenced significant differences, namely increased PWS by 67%, wall strain by 320% and displacement by 177%. Another interesting finding was that several constitutive models overestimated the ultimate tensile strength of the tissue. [PERSON] et al. (2018) tested the relevance of considering the three aortic wall layers--in particular, whether the intima layer also has a considerable load-bearing effect--by developing CSM digital twins of uniaxial tensile tests. Their analysis showed that the intima layer is stiffer among the layers and contributes significantly to the load bearing of the wall. Significant differences were found in considering three or only one layer--approximately 30% concerning the stresses and a maximum of 53% in displacements. On the topic of aorta blood flow, there are also open questions regarding the modelling of flow rheology and turbulence in large arteries. Although blood presents non-Newtonian behaviour, which is more evident for lower velocity regimes, we found contradictory evidence in our research regarding this topic. For instance, in the works of [PERSON] and [PERSON] (2018), [PERSON] et al. (2018) and [PERSON] et al. (2018), the authors depicted that using rheological models did not significantly alter the numerical results in ATAA, AAA and healthy aortas. [PERSON] et al. (2018) and [PERSON] et al. (2018) studied the same topic in AD and saccular aneurysms and found that modelling the non-Newtonian behaviour of blood impacted the numerical results. This evidence suggests that the pseudoplastic and viscoelastic features of blood are only relevant for lower shear rates, which are uncommon in large arteries but do occur in stagnant flow and recirculation zones. Regarding turbulence, the vast majority of numerical models opted for imposing laminar flow. However, it is known that in diseased and healthy (although rare) aortas, turbulent flow may occur during instances of the cardiac cycle. [PERSON] et al. (2018) and [PERSON] et al. (2018) used Direct Numerical Simulations (DNS) to model the turbulence in abdominal aortic stenosis and idealised geometries and found no significant differences in the numerical results. The group of [PERSON] et al. (2018) developed CFD models using the Galerkin method and suggested that the turbulence had a significant impact on pressure distributions ([PERSON] et al., 2018). Moreover, [PERSON] et al. (2018) used LES modelling to study the correlation between turbulent kinetic energy and abnormal flow on stenosed models. They found variations of around 15% in turbulent kinetic energy estimations and good agreement with MRI data when turbulence was modelled.