CALCULATION OF VISCOELASTIC FLOW USING MOLECULAR-MODELS - THE CONNFFESSIT APPROACH

A new method for numerical calculation of viscoelastic flow based on simulation of molecular models of polymers is presented. The CONNFFESSIT (Calculation of Non-Newtonian Flow: Finite Elements and Stochastic Simulation Technique) approach directly combines standard finite element methods as currently used in the calculation of viscoelastic flow with stochastic simulations of polymer dynamics and thus obviates the need for a rheological constitutive equation to describe the fluid. The stresses are obtained from the molecular configurations rather than from constitutive equations. As an illustration of the method, the time development of plane Couette flow is studied for the upper-convected Maxwell, Oldroyd-B, FENE-P and FENE fluids. For the upper-convected Maxwell, Oldroyd-B and FENE-P models comparisons with analytical and existing numerical solutions are presented. Significant deviations between the behavior of the FENE-P and FENE models for the start-up of plane Couette flow are found.