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-   -   Flow Around a Cylinder (http://www.cfd-online.com/Forums/openfoam/67889-flow-around-cylinder.html)

ronaldo August 30, 2009 02:45

Flow Around a Cylinder
 
Hi,

I am trying to model a flow around a cylinder 2D using simpleFoam.The Velocity is 3m/s and The turbulence model is k-epsilon Standard.
The dimension of the cylinder is 0.1 m diameter.

How could i set the Boundary Condition for Wall- Top and Bottom to get no Slip?

What about the Cylinder-Wall?

Please it ist very important for me and I would greatly appreciate it if you could send me an Answer or a case like that.

hansel August 30, 2009 16:10

In the boundaryField section of your first U file you would have something like:

minY
{
type fixedValue;
value uniform (0 0 0);
}

where minY is what ever name you gave your sides and / or the cylinder-wall.

See the tutorials for more examples.

ronaldo August 31, 2009 03:51

Thanks Hansel!
My Boundary Condition and so on look like:

FoamFile
{
version 2.0;
format ascii;
class volVectorField;
object U;
} //
//
dimensions [0 1 -1 0 0 0 0];
internalField uniform (0 0 0);
boundaryField
{
Rohrwand
{
type fixedValue;
value uniform (0 0 0);
}
Outlet_Pres
{
type zeroGradient;
}
Inlet_Vel
{
type fixedValue;
value uniform (2 0 0);
}
Sym_Wand
{
type symmetry;
}
frontAndBackPlanes
{
type empty;
}
}
dimensions [0 2 -2 0 0 0 0];
internalField uniform 0;
boundaryField
{
Rohrwand
{
type zeroGradient; ;
}
Outlet_Pres
{
type fixedValue;
value uniform 0;
}
Inlet_Vel
{
type zeroGradient;
}
Sym_Wand
{
type symmetry;
}
frontAndBackPlanes
{
type empty;
}
}
// ************************************************** *********************** //
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object k;
} //
//
dimensions [0 2 -2 0 0 0 0];
internalField uniform 0.87;
boundaryField
{
Rohrwand
{
type zeroGradient;
}
Outlet_Pres
{
type zeroGradient;
}
Inlet_Vel
{
type fixedValue;
value uniform 0.87;
}
Sym_Wand
{
type symmetry;
}
frontAndBackPlanes
{
type empty;
}
}
// ************************************************** *********************** //
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object epsilon;
} //
//
dimensions [0 2 -3 0 0 0 0];
internalField uniform 8579.621;
boundaryField
{
Rohrwand
{
type zeroGradient;
}
Outlet_Pres
{
type zeroGradient;
}
Inlet_Vel
{
type fixedValue;
value uniform 8579.621;
}
Sym_Wand
{
type symmetry;
}
frontAndBackPlanes
{
type empty;
}
}
// ************************************************** *********************** //
dimensions [0 2 -1 0 0 0 0];
internalField uniform 0;
boundaryField
{
Rohrwand
{
type nutWallFunction;
Cmu 0.09;
kappa 0.41;
E 9.8;
value uniform 0;
}
Outlet_Pres
{
type calculated;
value uniform 0;
}
Inlet_Vel
{
type calculated;
value uniform 0;
}
Sym_Wand
{
type calculated;
value uniform 0;
}
frontAndBackPlanes
{
type empty;
}
}
// ************************************************** *********************** //
FoamFile
{
version 2.0;
format ascii;
class volSymmTensorField;
object R;
} //
//
dimensions [0 2 -2 0 0 0 0];
internalField uniform (0 0 0 0 0 0);
boundaryField
{
Rohrwand
{
type zeroGradient;
}
Outlet_Pres
{
type zeroGradient;
}
Inlet_Vel
{
type fixedValue;
value uniform (0 0 0 0 0 0 0);
}
Sym_Wand
{
type symmetry;
}
frontAndBackPlanes
{
type empty;
}
}
// ************************************************** *********************** //
FoamFile
{
version 2.0;
format ascii;
class polyBoundaryMesh;
location "constant/polyMesh";
object boundary;
} //
//
5(
Rohrwand
{
type wall;
physicalType wallFunctions;
nFaces 100;
startFace 182530;
}
Outlet_Pres
{
type patch;
physicalType outlet;
nFaces 300;
startFace 182630;
}
Inlet_Vel
{
type patch;
physicalType inlet;
nFaces 100;
startFace 182930;
}
Sym_Wand
{
type symmetryPlane;
nFaces 700;
startFace 183030;
}
frontAndBackPlanes
{
type empty;
nFaces 183130;
startFace 183730;
}
)
// ************************************************** *********************** //
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "constant";
object RASProperties;
} //
//
RASModel kEpsilon;
turbulence on;
printCoeffs on;
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "constant";
object transportProperties;
} //
//
transportModel Newtonian;
nu nu [0 2 -1 0 0 0 0] 1.46e-05;
CrossPowerLawCoeffs
{
nu0 nu0 [0 2 -1 0 0 0 0] 0;
nuInf nuInf [0 2 -1 0 0 0 0] 0;
m <> [0 0 0 0 0 0 0] 0;
n <> [0 0 0 0 0 0 0] 0;
}
BirdCarreauCoeffs
{
nu0 nu0 [0 2 -1 0 0 0 0] 0;
nuInf nuInf [0 2 -1 0 0 0 0] 0;
k <> [0 0 0 0 0 0 0] 0;
n <> [0 0 0 0 0 0 0] 0;
}
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object nuTilda;
} // *

//
dimensions [0 2 -1 0 0 0 0];
internalField uniform 0;
boundaryField
{
Rohrwand
{
type zeroGradient;
}
Outlet_Pres
{
type zeroGradient;
}
Inlet_Vel
{
type fixedValue;
value uniform 0;
}
Sym_Wand
{
type symmetry;
}
frontAndBackPlanes
{
type empty;
}
}
// ************************************************** *********************** //
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object fvSolution;
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
turbulenceModel kEpsilon;
turbulence on;
laminarCoeffs
{}
kEpsilonCoeffs
{
Cmu Cmu [0 0 0 0 0 0 0] 0.09;
C1 C1 [0 0 0 0 0 0 0] 1.44;
C2 C2 [0 0 0 0 0 0 0] 1.92;
alphaEps alphaEps [0 0 0 0 0 0 0] 0.76923;
}

I get this Error when i start the Simulation: Inconsistent Patch and patchField types for patch type symmetryPlane and patchField type symmety

When i change SymmetryPlane to slip or Wall , my solution is absurdity.

I need Help please!

gocarts August 31, 2009 09:29

symmetry should be symmetryPlane
 
Judging by your error message I think you need to replace:

Sym_Wand
{
type symmetry;
}

with:

Sym_Wand
{
type symmetryPlane;
}

within your case/0/* field files.

hansel September 14, 2009 11:25

I think the units on k are supposed to be [0 0 1 0 0 0 0]
and m [0 0 1 0 0 0 0]

ronaldo September 18, 2009 08:13

It is the units on omega! The units on k is [0 2 -2 0 0 0 0 ]


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