| krzychu111 |
January 9, 2019 08:42 |
High nut values in random place and time
4 Attachment(s)
Hi,
I'm working on a simple 2D flow. When I changed turbulence model from kEpsilon to kOmegaSST I noticed that simulation works fine for around 300-600 iterations but then in random cell nut value goes quite high (around~1-1000).
Depending on boundary conditions it happens on boundaries or somewhere on the internal field. From then whole simulation goes wrong and number of iterations for omega rises from 1-5 to 200-800 in a single time step. I already tried modifying boundary conditions and refining the mesh but it didn't solve my problem.
Does anybody got any idea what I've done wrong?
Enclosed pictures and boundary conditions.
Thanks a lot,
Krzysztof
p
Code:
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 2 -2 0 0 0 0];
internalField uniform 0;
boundaryField
{
#includeEtc "caseDicts/setConstraintTypes"
inlet-aa
{
type zeroGradient;
}
inlet-bb
{
type zeroGradient;
}
outlet-close
{
type fixedValue;
value uniform 0;
}
outlet-cc
{
type fixedValue;
value uniform 0;
}
upperwall-aa
{
type symmetry;
}
upperwall-cc
{
type symmetry;
}
axi-bb
{
type symmetry;
}
axi-close
{
type symmetry;
}
a
{
type zeroGradient;
}
b
{
type zeroGradient;
}
frontAndBackPlanes
{
type empty;
}
}
U
Code:
FoamFile
{
version 2.0;
format ascii;
class volVectorField;
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 1 -1 0 0 0 0];
internalField uniform (20 0 0);
boundaryField
{
#includeEtc "caseDicts/setConstraintTypes"
inlet-aa
{
type freestream;
freestreamValue $internalField;
}
inlet-bb
{
type freestream;
freestreamValue $internalField;
}
outlet-cc
{
type inletOutlet;
inletValue $internalField;
value $internalField;
}
outlet-close
{
type inletOutlet;
inletValue $internalField;
value $internalField;
}
a
{
type fixedValue;
value uniform (0 0 0);
}
b
{
type fixedValue;
value uniform (0 0 0);
}
upperwall-cc
{
type symmetry;
}
upperwall-aa
{
type symmetry;
}
axi-close
{
type symmetry;
}
axi-bb
{
type symmetry;
}
frontAndBackPlanes
{
type empty;
}
}
nut
Code:
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object nut;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 2 -1 0 0 0 0];
internalField uniform 0;
boundaryField
{
#includeEtc "caseDicts/setConstraintTypes"
inlet-aa
{
type freestream;
freestreamValue 1e-2;
/*type calculated;
value $internalField;*/
}
inlet-bb
{
type freestream;
freestreamValue 1e-2;
/*type calculated;
value $internalField;*/
}
outlet-close
{
type zeroGradient;
/*type calculated;
value $internalField;*/
//type fixedValue;
//value uniform 0;
}
outlet-cc
{
type zeroGradient;
/*type calculated;
value $internalField;*/
//type fixedValue;
//value uniform 0;
}
upperwall-cc
{
type symmetry
}
upperwall-aa
{
type symmetry
}
axi-close
{
type symmetry;
}
axi-bb
{
type symmetry;
//value uniform 0;
}
a
{
type nutkWallFunction;
value uniform 0;
}
b
{
type nutkWallFunction;
value uniform 0;
}
frontAndBackPlanes
{
type empty;
}
}
k
Code:
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object k;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 2 -2 0 0 0 0];
internalField uniform 1;
boundaryField
{
#includeEtc "caseDicts/setConstraintTypes"
inlet-aa
{
type turbulentIntensityKineticEnergyInlet;
intensity 0.05; // 5% turbulent intensity
value $internalField;
}
inlet-bb
{
type turbulentIntensityKineticEnergyInlet;
intensity 0.05; // 5% turbulent intensity
value $internalField;
}
outlet-close
{
type inletOutlet;
inletValue $internalField;
}
outlet-cc
{
type inletOutlet;
inletValue $internalField;
}
upperwall-cc
{
type symmetry
}
upperwall-aa
{
type symmetry
}
axi-close
{
type symmetry;
}
axi-bb
{
type symmetry;
}
a
{
type kqRWallFunction;
value uniform 0;
}
b
{
type kqRWallFunction;
value uniform 0;
}
frontAndBackPlanes
{
type empty;
}
}
omega
Code:
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object omega;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 0 -1 0 0 0 0];
internalField uniform 1e-10;//$turbulentOmega;
boundaryField
{
#includeEtc "caseDicts/setConstraintTypes"
inlet-aa
{
type inletOutlet;
inletValue $internalField;
value $internalField;
}
inlet-bb
{
type inletOutlet;
inletValue $internalField;
value $internalField;
}
outlet-cc
{
type inletOutlet;
inletValue $internalField;
value $internalField;
}
outlet-close
{
type inletOutlet;
inletValue $internalField;
value $internalField;
}
a
{
type omegaWallFunction;
value $internalField;
}
b
{
type omegaWallFunction;
value $internalField;
}
axi-close
{
type symmetry;
}
axi-bb
{
type symmetry;
}
upperwall-aa
{
type symmetry
}
upperwall-cc
{
type symmetry
}
frontAndBackPlanes
{
type empty;
}
}
|
