In this paper

the multibead-rod molecular model is used to simulate the molecular structure of the dilute solution of sesbania gum. The flow of sesba-nia gum solution in a circular tube model with successive abrupt contractions and expansions in a ratio of four to one is studied by both numerical and experimental methods. The finite element method is used in numerical simulation. No special treatment is required in calculating the vortex flow. The calculated pressure drops and flow patterns by this method are in a good agreement with the experimental ones. In the experimental study

the pressure drop is found to be a quadratic function of flow rate for both the Newtonian and non-Newtonian fluids (glycerine solution and sesbania gum solution). The results show that such a molecular model can be used successfully to replace the constitutive equation.