ON ALGEBRAIC EXTRA-STRESS MODELS FOR THE SIMULATION OF VISCOELASTIC FLOWS

A methodology is presented for the formulation of an algebraic extra-s tress model derivable from the Oldroyd-B constitutive equation for a v iscoelastic fluid. An implicit algebraic tensor relation is derived di rectly from the differential constitutive relation by involving a slow variation condition on the evolution of the deviatoric part of the ex tra-stress tensor. An explicit solution to this algebraic constitutive equation is then obtained using representation bases developed previo usly for the turbulent flow of Newtonian fluids. A series of validatio n flows are then studied to assess the accuracy and range of applicabi lity of the algebraic extra-stress model. (C) 1998 Elsevier Science B. V. All rights reserved.