Laminar boundary layer flow of power-law liquids over a plate

3 Laminar boundary layer flow of power-law liquids over a plate 

For the laminar flow of a power-law fluid, the only forces acting within the fluid are pme shearing forces, and no momentum transfer occms by eddy motion. A third degree polynomial approximation may be used for the velocity distribution  

The constants a to d are evaluated by applying the following boxmdaiy conditions  

Condition (7.9d) is necessary to ensure the continuity of the velocity at y = 5. Condition (7.9b) can be explained by the following physical reasoning. The shearing stress in the fluid increases towards the plate, where the velocity is zero. Thus, the change in the momentum of the fluid in the x-direction must be very small near the plate and the shear stress in the fluid therefore must approach a constant value so that equation (7.9b) is applicable. 

Evaluating the constants and incorporating them into equation (7.8)  

---