Shear Stress due to the Fluctuations

Figure 8.1 presents the shear stress due to the fluctuations as a function of the distance from the wall. Two important features emerge from this figure:

Figure 8.1: Shear stress as a function of distance
from the wall;

• For nearly half the distance normal to the wall, the ratio is constant.
• at the centre of the pipe shear stress goes to zero. However, the turbulent intensities do not vanish at the axis (refer to fig. 7.5).

Figure 8.2

Figure 8.2 again shows results close to the wall normalized with respect to the viscous units.