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April 16, 2015, 09:10
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Time continuity error & FAN patch
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#1 |
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New Member
Francesco
Join Date: Jul 2014
Posts: 26
Rep Power: 12  |
Hi all,
I try to simulate a ducted fan in the tail of a body. If the fixed jump is below 1000 there is no movment in the mass of air (Paraview cant plot the velocity or pressure field), if i increase the pressure jump after few iteration (simpleFoam) diverge in the time continuity error.. I don't know were the problem could be. Tell me all the information you need to uderstand what could be wrong. Thanks. |
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April 16, 2015, 09:30
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#2 |
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New Member
Francesco
Join Date: Jul 2014
Posts: 26
Rep Power: 12 |
P Initial condition
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 2 -2 0 0 0 0];
internalField uniform 0;
boundaryField
{
frontAndBack
{
type slip;
}
outlet
{
type fixedValue;
value uniform 0;
}
inlet
{
type zeroGradient;
}
lowerWall
{
type zeroGradient;
}
upperWall
{
type slip;
}
Corpo
{
type zeroGradient;
}
Case
{
type zeroGradient;
}
cyclicFaces_master
{
type fan;
patchType cyclic;
jump uniform 0;
value uniform 0;
jumpTable polynomial
1((2000 0));
}
cyclicFaces_slave
{
type fan;
patchType cyclic;
value uniform 0;
}
}
// ************************************************************************* //
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volVectorField;
location "0";
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 1 -1 0 0 0 0];
internalField uniform (0 0 0);
boundaryField
{
frontAndBack
{
type slip;
}
outlet
{
type inletOutlet;
inletValue uniform (0 0 0);
value uniform (0 0 0);
}
inlet
{
type fixedValue;
value uniform (0 0 0);
}
lowerWall
{
type slip;
}
upperWall
{
type slip;
}
Corpo
{
type fixedValue;
value uniform (0 0 0);
}
Case
{
type fixedValue;
value uniform (0 0 0);
}
cyclicFaces_master
{
type cyclic;
}
cyclicFaces_slave
{
type cyclic;
}
}
// ************************************************************************* //
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object omega;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 0 -1 0 0 0 0];
internalField uniform 226;
boundaryField
{
frontAndBack
{
type slip;
}
outlet
{
type inletOutlet;
inletValue uniform 2.26;
value uniform 2.26;
}
inlet
{
type fixedValue;
value uniform 2.26;
}
lowerWall
{
type slip;
}
upperWall
{
type slip;
}
Corpo
{
type omegaWallFunction;
value uniform 226;
Cmu 0.09;
kappa 0.41;
E 9.8;
beta1 0.075;
value uniform 226;
}
Case
{
type omegaWallFunction;
value uniform 226;
Cmu 0.09;
kappa 0.41;
E 9.8;
beta1 0.075;
value uniform 226;
}
cyclicFaces_master
{
type cyclic;
}
cyclicFaces_slave
{
type cyclic;
}
}
// ************************************************************************* //
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object nut;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 2 -1 0 0 0 0];
internalField uniform 0;
boundaryField
{
frontAndBack
{
type calculated;
value uniform 0;
}
outlet
{
type calculated;
value uniform 0;
}
inlet
{
type calculated;
value uniform 0;
}
lowerWall
{
type calculated;
value uniform 0;
}
upperWall
{
type calculated;
value uniform 0;
}
Corpo
{
type nutkWallFunction;
Cmu 0.09;
kappa 0.41;
E 9.8;
value uniform 0;
}
Case
{
type nutkWallFunction;
Cmu 0.09;
kappa 0.41;
E 9.8;
value uniform 0;
}
cyclicFaces_master
{
type cyclic;
}
cyclicFaces_slave
{
type cyclic;
}
}
// ************************************************************************* //
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object k;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 2 -2 0 0 0 0];
internalField uniform 0.105;
boundaryField
{
frontAndBack
{
type slip;
}
outlet
{
type inletOutlet;
inletValue uniform 0.105;
value uniform 0.105;
}
inlet
{
type fixedValue;
value uniform 0.105;
}
lowerWall
{
type slip;
}
upperWall
{
type slip;
}
Corpo
{
type kqRWallFunction;
value uniform 0.105;
}
Case
{
type kqRWallFunction;
value uniform 0.105;
}
cyclicFaces_master
{
type cyclic;
}
cyclicFaces_slave
{
type cyclic;
}
}
// ************************************************************************* //
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
solvers
{
p
{
solver GAMG;
tolerance 1e-7;
relTol 0.01;
smoother GaussSeidel;
nPreSweeps 0;
nPostSweeps 2;
cacheAgglomeration on;
agglomerator faceAreaPair;
nCellsInCoarsestLevel 10;
mergeLevels 1;
}
U
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-8;
relTol 0.1;
nSweeps 1;
}
k
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-8;
relTol 0.1;
nSweeps 1;
}
omega
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-8;
relTol 0.1;
nSweeps 1;
}
}
SIMPLE
{
nNonOrthogonalCorrectors 0;
}
potentialFlow
{
nNonOrthogonalCorrectors 10;
}
relaxationFactors
{
fields
{
p 0.4;
}
equations
{
U 0.7;
k 0.7;
omega 0.7;
}
}
cache
{
grad(U);
}
// ************************************************************************* //
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April 22, 2015, 13:14
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#3 |
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New Member
Francesco
Join Date: Jul 2014
Posts: 26
Rep Power: 12 |
Ok,after some try i think that the error become from the inlet boudary condition that is a fixedInletValue of 0. When i increase the velocity the continuity error remain small.
A question, wich BC i have to use, if i want that there is no inlet and outlet constrain. I mean, if i want to simulate a fan in a free air without knowing the fan mass flow, only the pressure jump... |
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April 22, 2015, 13:36
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#4 |
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Member
Alexander Bartel
Join Date: Feb 2015
Location: Germany
Posts: 97
Rep Power: 11 |
Hi zephiro,
I have copied this BCs from some tutorial for my case, when I want to let the BCs be computed Code:
inlet
{
type pressureInletOutletVelocity;
phi phi;
value $internalField;
}
and Code:
outlet
{
type inletOutlet;
inletValue $internalField;
value $internalField;
}
I hope it helps otherwise the calculated BC could help... just a guess http://cfd.direct/openfoam/user-guide/boundaries/ regards Alex |
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April 22, 2015, 13:39
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#5 |
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New Member
Francesco
Join Date: Jul 2014
Posts: 26
Rep Power: 12 |
Thanks for your reply, now i try youre suggestion, i'm sure it will work.
Best regards Francesco |
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