A Study of Viscoelastic Fluid Flow : 3rd Report, Turbulent Flow in a Circular Pipe

Abstract

Dilute solutions of high molecular weight linear polymers with viscoelastic properties display significant reduction of frictional resistance in the turbulent pipe flow. This anomalous phenomenon is analytically treated with the concept that the turbulence intensity is partially surpressed by the elasticity of fluid. Combination of Weissenberg assumption and the power law for non-Newtonian viscosity is adopted as the flow model. The expression of the friction factor λ derived as the function of rheological constant n and two dimensionless numbers R₆ and N₆ includes Karman-Prandtl's formula for Newtonian fluids and Dodge-Metzner's formula for non-elastic, non-Newtonian fluids as special cases.