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| \\      /  F ield         | foam-extend: Open Source CFD                    |
|  \\    /   O peration     | Version:     4.1                                |
|   \\  /    A nd           | Web:         http://www.foam-extend.org         |
|    \\/     M anipulation  |                                                 |
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#
#+TITLE: UCM model stabilization
#+AUTHORS: Fernandes, C., De Araujo, M.S.B., Ferrás, L.L., Nóbrega, J.M.


This tutorial was prepared to illustrate the new stabilization approach for viscoelastic constitutive models proposed in:

Fernandes, C., De Araujo, M.S.B., Ferras, L.L., Nobrega, J.M.,
Improvements in the OpenFOAM numerical code for simulation of
steady-state differential viscoelastic flows, 11th OpenFOAM Workshop
Guimarães, Portugal, June 26 - 30, 2016

and

De Araujo, M.S.B., Ferras, L.L.,Fernandes, C.,Nobrega, J.M.,
Improvements ans assessment of the integral viscoelastic solver in OpenFOAM, 11th OpenFOAM Workshop
Guimarães, Portugal, June 26 - 30, 2016


It comprises 2 case studies for the flow in a 4:1 abrupt contraction of an UCM viscoelastic fluid, for De=1

- UCM_Orig - employs the original formulation that diverges before reaching the endtime

- UCM_Stab - employs the new stabilized formulation that allows to achieve convergence for all time steps

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Notes
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(1) To use the new stabilized formulation the value of etaStab should be provided in "constant/viscoelasticProperties". If ommited the solver uses the original formulation

(2) Based on several studies performed, the value of etaStab should be similar to etaP