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February 18, 2013, 06:46 
interFoam algorithm

#1 
New Member
Pierre HORGUE
Join Date: May 2009
Posts: 26
Rep Power: 9 
Hi ,
For each time step, I found that the order of the computations is a little bit strange. 1) It computes the new surface force term using the alpha field at the time "n" Code:
twoPhaseProperties.correct(); Code:
#include "alphaEqnSubCycle.H" Code:
//  Pressurevelocity PIMPLE corrector loop while (pimple.loop()) { #include "UEqn.H" //  Pressure corrector loop while (pimple.correct()) { #include "pEqn.H" } if (pimple.turbCorr()) { turbulence>correct(); } } It seems more logical to update the surface force term (step 1) just after computing the new alpha field. In my mind, the algorithm should be : 1) update properties time "n" 2) compute implicitly velocitypressure field "n+1" 3) compute alpha field "n+1" using the velocitypressure previously computed Am I wrong ? Thank You, Pierre 

February 19, 2013, 07:20 

#2 
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Pierre HORGUE
Join Date: May 2009
Posts: 26
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I confirm what I said before, this is an error in the "interFoam" solver (and the derivated solvers).
In the H. Rusche thesis, page 162, we can see the following solution procedure : steps 14 : refer to the moving frame step 5 : transport "alpha1" step 6 : update properties (smooth gamma => curvature computation => surface force term) step 7 and 8 : PISOloop to compute pressurevelocity fields. Maybe this error should be reported to the OpenFOAM Foundation to correct it for the following versions. Pierre 

February 19, 2013, 08:51 

#3 
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Anton Kidess
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Location: Germany
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How are step 58 different than what is already implemented?
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February 19, 2013, 08:58 

#4 
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Pierre HORGUE
Join Date: May 2009
Posts: 26
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In the current version of "interFoam", the step 6 is computed before the step 5.
First it computes the surface force term : Code:
twoPhaseProperties.correct(); Code:
#include "alphaEqnSubCycle.H" 

February 19, 2013, 10:50 

#5 
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Anton Kidess
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The interface curvature for the surface force term is calculated by calling interface.correct() after the alphaEqnSubCycle.
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February 19, 2013, 11:03 

#6 
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Pierre HORGUE
Join Date: May 2009
Posts: 26
Rep Power: 9 
Ok, I had inverted the "correct" function of twoPhaseMixture for the viscosity with the "correct" function of interfaceProperties for the curvature.
Thank you for your reply 

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