Problems with volScalarField

niklas · November 28, 2005, 04:30

Why not?
volScalarField pf = pow(10,25.0)*pow(max(0.0, alpha - alphaMax), 10.0);

different results?
does the pf field differ or what do you mean?

N

alberto · November 28, 2005, 14:42

I'm still working on twoPhaseEulerFoam to make granular pressure, radial distribution functions, and frictional stress models runtime selectable.

The problem happens with frictional stress models, where pf is the frictional pressure.

If I use the first piece of code, I get solution singularity at the second time step due to an abnormal value in the granular pressure, which is related to pf.
If I use the second piece of code, the calculation goes on regularly.
However, it seems the initialization of the pf field has some effect. I mean the forAll cycle doesn't seem to overwrite all initial values also in the second piece of code.

Alberto

alberto · November 28, 2005, 17:05

You were right. The problem was that I forgot the Foam::max(alpha-alphaMax, 0.0).

Thank you again

P.S. How are you?

Alberto :-)

November 28, 2005, 04:30	Why not? volScalarField pf =	#1
niklas Super Moderator Niklas Nordin Join Date: Mar 2009 Location: Stockholm, Sweden Posts: 693 Rep Power: 29	Why not? volScalarField pf = pow(10,25.0)*pow(max(0.0, alpha - alphaMax), 10.0); different results? does the pf field differ or what do you mean? N

November 28, 2005, 14:42	I'm still working on twoPhaseE	#2
alberto Senior Member Alberto Passalacqua Join Date: Mar 2009 Location: Ames, Iowa, United States Posts: 1,912 Rep Power: 36	I'm still working on twoPhaseEulerFoam to make granular pressure, radial distribution functions, and frictional stress models runtime selectable. The problem happens with frictional stress models, where pf is the frictional pressure. If I use the first piece of code, I get solution singularity at the second time step due to an abnormal value in the granular pressure, which is related to pf. If I use the second piece of code, the calculation goes on regularly. However, it seems the initialization of the pf field has some effect. I mean the forAll cycle doesn't seem to overwrite all initial values also in the second piece of code. Alberto __________________ 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.

November 28, 2005, 17:05	You were right. The problem wa	#3
alberto Senior Member Alberto Passalacqua Join Date: Mar 2009 Location: Ames, Iowa, United States Posts: 1,912 Rep Power: 36	You were right. The problem was that I forgot the Foam::max(alpha-alphaMax, 0.0). Thank you again P.S. How are you? Alberto :-) __________________ 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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