Figure 15

Influence of the wall velocity on boundary layer thickness, friction coefficient and wall shear stress. The bottom figure shows the normalised thickness of the boundary layer during in- (left) and outward motion (right) of the wall in the dynamic configuration presented in the third Additional file. Compared to zero wall velocity the boundary layer thickness in systole (ν _w = 5.1 mm/s) is increased in the entrance region of the deformation while it is decreased in the outlet region, in diastole (ν _w = -6.8 mm/s) the situation is vice versa. The influence on viscous friction and wall shear stress is small and thus the difference in pressure loss over the deformation compared to ν _w = 0 is small (δp ≈ 1% of Δp).