Fig. 1.

Normalized velocity profiles, ν = ν_z/(PR²/4η_∞), for steady fully-developed flow in a tube as a function of normalized radius, ξ = r/R, for a) α = 0.4 and different values of q, and b) q = 0.6 and different values of α. Cases α = 0 and q = −1 correspond to Poiseuille flow of a Newtonian fluid, case q = 1 corresponds to Casson flow