## 3 Results
### Baseline Case
the separation location was identified at \(x/c=0.66\) for both the numerical and experimental results; whereas the reattachment location for the numerical result was slightly higher than the experimental. The reattachment location was at \(x/c=1.1\) from the experimental result and \(x/c=1.13\) from the numerical result. Figure 11 shows the pressure coefficient along the hump wall. Figure 8: Instantaneous iso-surface of \(Q=150\) showing complex flow structures. Figure 7: Instantaneous u-velocity. Figure 9: Instantaneous iso-surface of vorticity magnitude. The pressure coefficient, \(C_{p}\), showed the adverse pressure gradient produced on the hump wall, which resulted in flow separation. The pressure increased until the flow reached its location at \(x/c=0.66\), followed by a sharp decrease of \(-C_{p}\) at that position, which indicated the flow separation at location \(x/c=0.66\). Reattachment at the hump's trailing edge is also found in the figure. The reason for the discrepancy between the numerical and experimental results in the separated region could be due to the end plate effects in the experimental measurements. This was also supported by the results shown by [PERSON] et al. [50], where the numerical results considering the end-plates gave better agreement with the experimental values. Noteworthy is that the numerical simulations for this work were carried out without the consideration of end plates. Figure 12 shows the mean u-velocity component comparisons at different streamwise stations. The stations were selected locations that were comprised of pre-separation, separation, and post-separation regions, located at \(x/c=0.65,x/c=0.80,x/c=0.90,x/c=1.1,x/c=1.2\), and \(x/c=1.3\). The difference between the experimental (orange dotted line) and numerical results (blue solid line) was minimal and therefore showed good agreement. The results were consistent with similar numerical simulations carried out in [19; 34; 42; 44; 51]. However, the usage of high-fidelity models could improve the numerical predictions. Locations \(x/c=0.80\) and \(x/c=0.90\) were the locations inside the separation region and could be identified from the velocity boundary layer profile  
Figure 4:0 Pressure coefficient. Figure 4:1 Skin friction coefficient. seen in Figure 4:2 The other locations were unaffected by flow separation, in which the first one, i.e, \(x/c=0.65\), was the location upstream of the separation and \(x/c=1.3\) was the downstream location of the separation. The Reynolds shear stresses were compared to the experimental values. Figure 13 shows the mean Reynolds shear stresses comparisons at similar streamwise locations that were shown in Figure 4:3 The numerical results underpredicted the Reynolds stresses compared to the experimental particle image velocimetry (PIV) results. The most noticeable difference was found at location \(x/c=0.65\), which showed greater shear. The PIV technique inherently had measurement uncertainties close to the wall as seed particles could not get very close to the wall. This was one potential reason for the difference between the numerical and experimental results shown in Figure 4:4 The error sources of the PIV technique and relative uncertainties associated with it were mentioned in [52]. [PERSON] et al. discussed Reynolds stress uncertainties due to PIV errors [53]. This inherent error is equally problematic for flows suffering separation. It was noted in [44] that the PIV experimental value just upstream of the flow separation is not sufficiently accurate in the near wall region. Figure 13 represents the mean \(uv\) normalized stress components and indicates added shear stress accompanied by the separation. Figure 4:5 Normalized mean velocity along \(y/c\) at different streamwise stations.