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March 31, 2011, 09:51 |
twoPhaseEulerFoam variables
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#1 |
Member
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Hi all
I was going through the code of twoPhaseEulerFoam and I have some questions about the variables in a part of alphaEqn.H and I'd be thankful if anyone could help me identify their use. What is phic used for? It is initialised as Code:
surfaceScalarField phic = phi; Code:
surfaceScalarField alphaf = fvc::interpolate(alpha); Code:
surfaceScalarField phipp = ppMagf*fvc::snGrad(alpha)*mesh.magSf(); |
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April 1, 2011, 02:45 |
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#2 |
Senior Member
Alberto Passalacqua
Join Date: Mar 2009
Location: Ames, Iowa, United States
Posts: 1,912
Rep Power: 36 |
Hi,
phipp is a term used only if the ppMagf model is used. In such case, the momentum equation for phase a has an additional pressure gradient grad(pa). If you proceed as in the derivation of phase a "pressure equation", but keep that equation written in terms of alpha, understand the origin of phipp. Hint: grad(pa) = G(alpha) * grad(alpha), where G(alpha) = ppMagf = d(pa)/d(alpha). Best,
__________________
Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. |
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November 25, 2011, 23:48 |
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#3 |
New Member
Kshitij kunte
Join Date: Jun 2011
Posts: 18
Rep Power: 14 |
Hi Alberto,
I have one question about the ppmagf's usage, according to my understanding the ppmagf model is implemented when the kinetic theory is off, ie when the value of g0 > 0. Then why does its definition involve the kinetic theory particle pressure "pa". Or I'm wrong in getting this. I'm a newbee to C++ and have not understood the code yet would you please clarify. Thanks in advance. |
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November 26, 2011, 21:00 |
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#4 |
Senior Member
Alberto Passalacqua
Join Date: Mar 2009
Location: Ames, Iowa, United States
Posts: 1,912
Rep Power: 36 |
The currently implemented ppMagf does not involve the kinetic theory model. I used "pa" in comment #2 to suggest how to extend the current treatment of the particle pressure in the alpha equation only implemented when the ppMagf model is used also to the case when the kinetic theory is used.
Best,
__________________
Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. |
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