FEEDBACK BOUNDARY OF 4:1 ROUNDED CONTRACTION SLIP FLOW FOR OLDROYD-B FLUID BY FINITE ELEMENT

The driven force feedback in viscoelastic flow is a technique to enforce converged solution of Oldroyd-B fluid on the basis of semi-implicit Taylor-Galerkin finite element method for 4:1 contraction geometry with rounded corner meshes. Meanwhile in the numerical computation, the Phan-Thien slip rule is applied to complete the slip velocity along the die wall. After application of the slip condition, the severe stress near die exit and the vortex size around contraction corner are clearly reduced. This simulation is modeled with the Navier-Stokes and Oldroyd-B equations in two-dimensional planar isothermal incompressible creeping flow. The non-linear differential models are discretised to system of linear equations with semi-implicit Taylor-Galerkin finite element method. In addition, the Streamline-Upwind/Petrov-Galerkin and velocity gradient recovery are accuracy and the stability schemes to stabilize an approximate solution. The optimal slip velocity is modified step by step by critical slip coefficient to set the slip condition at the wall and when the solutions of slip and no-slip cases are compared with analytic solution, the outcome of slip condition shows better conformity to real results.