CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

MRFSimpleFoam + AMI in 2.1.0 vs GGI in 1.5-dev

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 26, 2012, 10:44
Default MRFSimpleFoam + AMI in 2.1.0 vs GGI in 1.5-dev
  #1
New Member
 
Marcel Günter
Join Date: Mar 2012
Location: Stuttgart, Germany
Posts: 20
Rep Power: 14
marcelgt87 is on a distinguished road
hello everyone,

I recently managed to run the ERCOFTAC Centrifugal Pump validation test case in a recent version of OpenFoam 1.5-dev with the help of this forum (thanks again!)

now I want to run this exact same case in OpenFoam 2.1.0 with AMI interfaces instead of GGI.

the turbulence model (k-epsilon) and all the boundary conditions are exactly the same as in the 1.5-dev case except for the pressure-outlet. in 1.5-dev the pressure outlet is set as "fixedmeanvalue", unfortunately this bc doesn't exist any more in 2.1.0, so i defined it as "fixedvalue".

the case converges, though not as good as in 1.5-dev.
the results for U make sense but still differ from those i got in 1.5-dev.
what puzzles me the most are the results for p. the pressure gradient is just inverted!

see for yourselves, i uploaded the pictures.

does anyone have an idea how this could happen or what i could do to get better results?

best regards,
Marcel
Attached Images
File Type: jpg ecp_15dev_p.jpg (40.6 KB, 125 views)
File Type: jpg ecp_15dev_umag.jpg (49.1 KB, 106 views)
File Type: jpg ecp_210_p.jpg (47.8 KB, 99 views)
File Type: jpg ecp_210_umag.jpg (52.5 KB, 87 views)
File Type: jpg ecp_210_res.jpg (43.0 KB, 77 views)
marcelgt87 is offline   Reply With Quote

Old   June 27, 2012, 09:24
Default
  #2
Member
 
Paulo Alexandre Costa Rocha
Join Date: Mar 2009
Posts: 71
Rep Power: 17
paulo is on a distinguished road
Hi,

Are the two cases rotating in the same direction?

Best Regards,

Paulo Rocha
paulo is offline   Reply With Quote

Old   June 27, 2012, 09:37
Default
  #3
New Member
 
Marcel Günter
Join Date: Mar 2012
Location: Stuttgart, Germany
Posts: 20
Rep Power: 14
marcelgt87 is on a distinguished road
yes, they are. i just checked it again, to be safe.
marcelgt87 is offline   Reply With Quote

Old   June 29, 2012, 05:52
Default
  #4
Senior Member
 
Albrecht vBoetticher
Join Date: Aug 2010
Location: Zürich, Swizerland
Posts: 240
Rep Power: 17
vonboett is on a distinguished road
could you please post your initial U and p / p_rgh file and fvSolution, fvSchemes? I probably can't help put I'd like to take a look.
vonboett is offline   Reply With Quote

Old   June 29, 2012, 05:54
Default
  #5
Senior Member
 
Albrecht vBoetticher
Join Date: Aug 2010
Location: Zürich, Swizerland
Posts: 240
Rep Power: 17
vonboett is on a distinguished road
...because I think your geometry is qite challanging for your turbulence model. Did you try with LES in combination with DMM subgrid scale model developed by the LTT Rostock and a SimpleGridFilter to allow backscatter? This would account better for the Influence of your geometry on the turbulence.
vonboett is offline   Reply With Quote

Old   July 2, 2012, 04:33
Default
  #6
Member
 
wided
Join Date: Jul 2010
Posts: 54
Rep Power: 16
wiedangel is on a distinguished road
Hi marcelgt87,

I also wanted to do the same comparison you did using the ERCOFTAC validation case. This is because I also did not obtain the same P for a very simple case that I tried to compare using both approaches which you used ... It would be nice if you give some details about your schemes and solutions dictionaries.

Regards
wiedangel is offline   Reply With Quote

Old   July 2, 2012, 05:12
Default
  #7
New Member
 
Marcel Günter
Join Date: Mar 2012
Location: Stuttgart, Germany
Posts: 20
Rep Power: 14
marcelgt87 is on a distinguished road
sorry, that it took so long. here are my files for OF 2.1.0.

U:
Code:
internalField   uniform (0 0 0);

boundaryField
{
    INLET
    {
        type            surfaceNormalFixedValue;
	refValue	uniform -11.4;
    }
    OUTLET
    {
        type            zeroGradient;
    }
    BLADE_ROT
    {
        type            fixedValue;
        value           uniform (0 0 0);    
    }
    BLADE_STAT
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }
    HUB_SHROUD
    {
	type		empty;
    }
    AMI_INT
    {
	type		cyclicAMI;
	value		$internalField;
    }
    AMI_EXT
    {
	type		cyclicAMI;
	value		$internalField;
    }
}
p:
Code:
internalField   uniform 0;

boundaryField
{
    INLET
    {
        type            zeroGradient;
    }
    OUTLET
    {
        type            fixedValue;
	value		uniform 0;
    }
    BLADE_ROT
    {
        type            zeroGradient;
    }
    BLADE_STAT
    {
        type            zeroGradient;
    }
    HUB_SHROUD
    {
        type            empty;
    }
    AMI_INT
    {
	type		cyclicAMI;
	value		$internalField;
    }
    AMI_EXT
    {
	type		cyclicAMI;
	value		$internalField;
    }
}
fvSolutions:
Code:
solvers
{
    p
    {
        solver          GAMG;
        smoother        GaussSeidel;
        cacheAgglomeration true;
        nCellsInCoarsestLevel 20;
        agglomerator    faceAreaPair;
        mergeLevels     1;

        tolerance       1e-08;
        relTol          0.05;
    }

    pFinal
    {
        solver          GAMG;
        smoother        GaussSeidel;
        cacheAgglomeration true;
        nCellsInCoarsestLevel 10;
        agglomerator    faceAreaPair;
        mergeLevels     1;

        tolerance       1e-06;
        relTol          0;
    }

    "(U|k|epsilon)"
    {
        solver          smoothSolver;
        smoother        GaussSeidel;
        tolerance       1e-07;
        relTol          0.1;
    }

    "(U|k|epsilon)Final"
    {
        solver          PBiCG;
        preconditioner  DILU;

        tolerance       1e-05;
        relTol          0;
    }
}

PIMPLE
{
    nOuterCorrectors 4;
    nCorrectors     1;
    nNonOrthogonalCorrectors 0;
    pRefCell        0;
    pRefValue       0;
}

SIMPLE
{
    nNonOrthogonalCorrectors 0;
}

relaxationFactors
{
    fields
    {
        p               0.3;
    }
    equations
    {
        U               0.7;
        k               0.9;
        "epsilon.*"     0.9;
    }
}

cache
{
    grad(U);
}
fvSchemes:
Code:
ddtSchemes
{
    default         steadyState;
}

gradSchemes
{
    default         Gauss linear;
    grad(p)         Gauss linear;
    grad(U)         Gauss linear;
}

divSchemes
{
    default         none;
    div(phi,U)      Gauss limitedLinearV 1;
    div(phi,k)      Gauss limitedLinear 1;
    div(phi,epsilon) Gauss limitedLinear 1;
    div(phi,R)      Gauss limitedLinear 1;
    div(R)          Gauss linear;
    div(phi,nuTilda) Gauss limitedLinear 1;
    div((nuEff*dev(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
    default         none;
    laplacian(nuEff,U) Gauss linear corrected;
    laplacian((1|A(U)),p) Gauss linear corrected;
    laplacian(DkEff,k) Gauss linear corrected;
    laplacian(DepsilonEff,epsilon) Gauss linear corrected;
    laplacian(DREff,R) Gauss linear corrected;
    laplacian(DnuTildaEff,nuTilda) Gauss linear corrected;
}

interpolationSchemes
{
    default         linear;
    interpolate(U)  linear;
}

snGradSchemes
{
    default         corrected;
}

fluxRequired
{
    default         no;
    p               ;
}
unfortunately my background knowledge about all the settings in fvSchemes and fvSolutions is quite limited, so i copied those files from a tutorial case.

@wiedangel: did you succeed? did you get any results with that comparison? could you give me some more details about what exactly you did?

thank you!
marcel
marcelgt87 is offline   Reply With Quote

Old   July 2, 2012, 09:32
Default
  #8
Senior Member
 
Albrecht vBoetticher
Join Date: Aug 2010
Location: Zürich, Swizerland
Posts: 240
Rep Power: 17
vonboett is on a distinguished road
Hi Marcel, I would use OUTLET { type zeroGradient; } for p since I had some funny coordinate-dependent effects using fixedValue 0 at my outlets.
vonboett is offline   Reply With Quote

Old   July 2, 2012, 10:06
Default
  #9
New Member
 
Marcel Günter
Join Date: Mar 2012
Location: Stuttgart, Germany
Posts: 20
Rep Power: 14
marcelgt87 is on a distinguished road
i just tried to do what you said. i set the outlet to zerogradient. as a result openfoam tells me to provide a reference value for p. when i do that (refvalue 0 and refcell 0) the calculation doesn't converge and eventually crashes. i also tried setting the outlet as zerogradient and the inlet as fixedvalue 0, with the same result.

is there anything i overlooked?

regards,
marcel
marcelgt87 is offline   Reply With Quote

Old   July 2, 2012, 11:22
Default
  #10
Senior Member
 
Albrecht vBoetticher
Join Date: Aug 2010
Location: Zürich, Swizerland
Posts: 240
Rep Power: 17
vonboett is on a distinguished road
what does it look like when you use a high refvalue?
vonboett is offline   Reply With Quote

Old   July 2, 2012, 11:39
Default
  #11
New Member
 
Marcel Günter
Join Date: Mar 2012
Location: Stuttgart, Germany
Posts: 20
Rep Power: 14
marcelgt87 is on a distinguished road
quite the same
marcelgt87 is offline   Reply With Quote

Old   December 2, 2013, 19:40
Default
  #12
Member
 
Ye Zhang
Join Date: Dec 2009
Location: Delft,Netherland
Posts: 92
Rep Power: 17
kiddmax is on a distinguished road
Hi Marcel,

Could you please send me a copy of testcase of ERCOFTAC Centrifugal Pump? I did not download it successfully. Thank you so much!

My email address: dlutyezhang@gmail.com or you can use this mail to share it by Dropbox.

Again thanks

Best regards,
Ye
kiddmax is offline   Reply With Quote

Old   July 15, 2014, 11:57
Default
  #13
Member
 
Lisandro Maders
Join Date: Feb 2013
Posts: 98
Rep Power: 13
Lisandro Maders is on a distinguished road
Hey guys, did you sort the pressure problem? If so, what was the problem and how do you manage to fix that?


Appreciate a lot your answer!

Lisandro
Lisandro Maders is offline   Reply With Quote

Reply

Tags
ami, ggi, kepsilon, mrfsimplefoam

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Create a GeometricField of a given type on given patch? philippose OpenFOAM Programming & Development 4 August 12, 2013 13:41
GGI implementation in MRFSimpleFoam amgode OpenFOAM Running, Solving & CFD 8 August 5, 2011 07:03
about MRFSimpleFoam and ggi wllmk1 OpenFOAM Running, Solving & CFD 0 February 5, 2011 05:52
OpenFOAM 1.5 dev LVDH OpenFOAM 98 May 5, 2010 18:01
[OpenFOAM] Paraview/Parafoam in OpenFoam 1.5 dev titio ParaView 0 December 9, 2009 13:13


All times are GMT -4. The time now is 15:45.