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

Flow Around a Cylinder

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 30, 2009, 02:45
Default Flow Around a Cylinder
  #1
Member
 
toto
Join Date: Jun 2009
Posts: 71
Rep Power: 17
ronaldo is on a distinguished road
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.
ronaldo is offline   Reply With Quote

Old   August 30, 2009, 16:10
Default
  #2
Senior Member
 
Steve Hansel
Join Date: Jun 2009
Location: Colorado, USA
Posts: 112
Rep Power: 17
hansel is on a distinguished road
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.
hansel is offline   Reply With Quote

Old   August 31, 2009, 03:51
Default
  #3
Member
 
toto
Join Date: Jun 2009
Posts: 71
Rep Power: 17
ronaldo is on a distinguished road
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!
ronaldo is offline   Reply With Quote

Old   August 31, 2009, 09:29
Default symmetry should be symmetryPlane
  #4
Senior Member
 
gocarts's Avatar
 
Richard Smith
Join Date: Mar 2009
Location: Enfield, NH, USA
Posts: 138
Blog Entries: 4
Rep Power: 17
gocarts is on a distinguished road
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.
__________________
Symscape, Computational Fluid Dynamics for all
gocarts is offline   Reply With Quote

Old   September 14, 2009, 11:25
Default
  #5
Senior Member
 
Steve Hansel
Join Date: Jun 2009
Location: Colorado, USA
Posts: 112
Rep Power: 17
hansel is on a distinguished road
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]
hansel is offline   Reply With Quote

Old   September 18, 2009, 08:13
Default
  #6
Member
 
toto
Join Date: Jun 2009
Posts: 71
Rep Power: 17
ronaldo is on a distinguished road
It is the units on omega! The units on k is [0 2 -2 0 0 0 0 ]
ronaldo is offline   Reply With Quote

Reply

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
benchmark: flow over a circular cylinder goodegg Main CFD Forum 12 January 22, 2013 11:47
Flow over a flat plate & Flow over a cylinder cfdxue Main CFD Forum 0 November 26, 2007 23:26
Anybody knows smth abt the flow around a cylinder? Wenxuan Main CFD Forum 3 March 20, 2007 16:19
Flow over a cylinder Anna Main CFD Forum 9 March 24, 2006 14:32
Flow Past a Cylinder Annie Main CFD Forum 2 March 31, 2002 00:02


All times are GMT -4. The time now is 15:31.