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Converged solutions of the Newtonian extrudate‐swell problem
Author(s) -
Georgiou Georgios C.,
Boudouvis Andreas G.
Publication year - 1999
Publication title -
international journal for numerical methods in fluids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 112
eISSN - 1097-0363
pISSN - 0271-2091
DOI - 10.1002/(sici)1097-0363(19990215)29:3<363::aid-fld792>3.0.co;2-d
Subject(s) - die swell , mathematics , reynolds number , finite element method , singularity , newtonian fluid , laminar flow , mechanics , rotational symmetry , geometry , mathematical analysis , physics , turbulence , materials science , thermodynamics , extrusion , metallurgy
Both the axisymmetric and the planar Newtonian extrudate‐swell problems are solved using the standard and the singular finite element methods. In the latter method, special elements that incorporate the radial form of the stress singularity are used around the exit of the die. The convergence of each of the two methods with mesh refinement is studied for various values of the Reynolds and the capillary numbers. The numerical results show that the singular finite elements perform well if coarse or moderately refined meshes are used, and appear to be superior to the standard finite elements only when the Reynolds number is low and the surface tension is not large. The standard finite elements perform better as the surface tension or the Reynolds number are increased. This implies that the effect of the stress singularity on the accuracy of the numerical solution in the neighborhood of the die exit becomes less significant when the Reynolds number is high or the surface tension is large. Copyright © 1999 John Wiley & Sons, Ltd.