A Study on the Constitutive Equation of Viscoelastic Fluids : 2nd Report, Converging and Diverging Flows in a V-Shaped Duct

Abstract

The viscoelastic properties which would be important in the unsteady flow fields in the Lagrangian sense are studied converging and diverging flows in a V-shaped duct. When the viscoelastic fluid flows slowly in the duct, the velocity profile can be approximated by that of a purely viscous, non-Newtonian fluid, applying the Denn model as the constitutive equation; and the differential equation for the velocity profile can be solved by a perturbation method regarding the "power law index" as a perturbation parameter. Using the velocity profile obtained, the stresses in the duct are analyzed. Results are in good agreement with the experimental results performed by Adams et al.