Numerical Simulation for Blood Flow - Microsurgery: Advances, Simulations, and Applications - page 197

from 80 to 120 mmHg. The range of blood pressure is determined by
referring to the healthy human condition.

5.4.6 Wall Shear Stress

Wall shear stress is most interesting hemodynamic parameter,
because it has relation to degeneration of vessel wall. Figure 5.22
shows the result of wall shear stress distribution on ICA at three
different states. The irst state is at 0.10 s of the pulsation cycle and
is shown in Fig. 5.22(a). The second is systole phase at 0.25 s and is
shown in Fig. 5.22(b). The third is diastole phase of 0.50 s, shown
in Fig. 5.22(c). The maximum wall shear stress is approximately 15
Pa at the bifurcation of ICA model, and its phase is diastole phase at
0.25 s. The lower limit of physiological wall shear stress ranges 10
Pa. 11 Locally high wall shear stress at the bifurcation is more than 15
Pa. Furthermore, higher wall shear stress occurs as the diameter of
blood vessel becomes narrow. The wall shear stress on the outside
of larger bifurcation is lower than 4 Pa and is nearly equal to 0 at all
times.

Figure 5.22 Wall shear stress. See also Color Insert.

5.4.7 Velocity Magnitude

Dashed line in Fig. 5.20 represents the cutting plane at separated
branch of ICA model to be a cross section. Also the velocity magnitude