The results of the derived analytical expressions for the flow velocity profile (i.e. Eqs. 17 and 18 with n = 1, k = µ, and ∂p/∂z = ∇P ) were compared to the results of this formula (i.e. Eq. 24) and they were identical. A sample of these comparisons is given in Figure . 3. Circular power law: the velocity profile for the flow of power law fluids through a circular tube of radius R is given by (see ):