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Sliding Mesh or rotor stator model implimentation

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Old   April 11, 2012, 07:58
Default Sliding Mesh or rotor stator model implimentation
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kid
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Hi Fomers,
This a very serious question guys, and would appreciate suggestions from every one.

What is state of implementing sliding mesh in OpenFOAM ( or with OpenFOAM201)?

We require to implement VAWT ( Vertical Axis Wind Turbine), Fixing the outer domain and rotating a cylindrical Mesh inside it having blade.stl .
Now another question comes up:
What should be the approach ? ( in getting 2 meshes ie cylinder with stl blades and outer domain)



Regards
CFDkid

PS: Any other suggestions !!!!
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Old   April 11, 2012, 09:41
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I would suggest you to have a look at the following tutorials:
Multi Reference Frames: tutorials/incompressible/MRFSimpleFoam/mixerVessel2D
Moving mesh: tutorials/incompressible/pimpleDyMFoam/propeller
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Old   April 12, 2012, 02:30
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@lore

Was using openFOAM201 , @/tutorial/incompressible/pimpleDyFoam did not find propeller case. Checked out by upgrading to openFoam210 and found the propeller case, working on it now. Will come up with question soon.
Also i decided to go for sliding mesh instead of moving Frame of Reference i.e the two case you suggested, i am trying out propeller one with pimpleDyFoam.
Is my decision ok ??

regards,
CFDkid


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Old   April 12, 2012, 04:02
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Yep, the propeller tutorial came out with the latest version of OF.
About your decision, it really depend on whether you want to run a steady or unsteady simulation.
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Old   April 12, 2012, 06:19
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@lore
I am just doing that propeller case, but things would get prity complicated for me if i implement a similar case.
Few questions!!!
1. What is the role of importing geometry , i do not know if at all it is required? ( At least the object which has to rotate ( suppose a turbine)).

2. How to i create the innerCylinder and innerCylinderSmall? (the sliding faces that would separate Rotor and Stator part of CFD domain)

3.How to create mesh
"surfaces=
innerCylinder
innerCylinderSmall
outerCylinder
propellerTip
propellerStem1
propellerStem2
propellerStem3
"
?

I use slome for geometry and mesh creation + simpleFoam GUI in CAELinux to for the OpenFoam case directory.
else I use discritizer.

But how should i approach for this case, really stuck man.
regards,

Last edited by kid; April 12, 2012 at 06:45. Reason: Clearity was needed
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Old   April 12, 2012, 06:31
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Have you looked already at the allRun script? That's all you need to run…
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Old   April 12, 2012, 06:41
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@lore
Yes i did dig inside. Also ran the case.
Everything fine with that case.

But if i want to implement another similar case.
Like a rotating cube in a regular inlet ---> outlet domain.

Now if you see that question of mine above, you would understand what i intended to ask.

regards
CFdkid
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Old   April 12, 2012, 07:16
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The easiest way is probably to enclose the mesh you want to rotate within a .stl cylinder then, in snappyHexMeshDict you'll need something like this:

Code:
refinementSurfaces
    {
        cylinder
        {
            level       (2 2);
            cellZone    cylinder;
            faceZone    cylinder;
            cellZoneInside  inside;
        }


    }
and then in your dynamicMeshDict:

Code:
solidBodyMotionFvMeshCoeffs
{
    cellZone        cylinder;

    solidBodyMotionFunction  rotatingMotion;
    rotatingMotionCoeffs
    {
        CofG        (0 0 0);
        radialVelocity (0 0 34); // deg/s
    }
}
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Old   April 12, 2012, 07:26
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@lore
That means , if we have a small cube to be rotated, we need to create a mesh file and enclose that mesh in cylindrical stl file. Then import that stl with mesh in OpenFoam and carry out the step you said.
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Old   April 12, 2012, 08:51
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Yes. I would you snappyHexMesh.
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Old   April 16, 2012, 07:01
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@Lore
Man, used snappyHexMesh to generate this cube with cylindrical mesh around mvCube.stl ( should have named it rotatingCube!! forgot).

mvCube.stl was made using Salome and stl binary was placed in /constant/ triSurface/
and accordingly changes were made in snappyHexMeshDict::geometry

Now is it sufficient and should i move to edit dynamicMeshDict? Or something missing?

Regards
CFDkid

@Lore
Thanks a ton man , this helpped me to learn snaapyHexMesh , though rotating a cube is still pending.
Attached Images
File Type: png snap_mvCube.png (5.2 KB, 85 views)
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Old   April 16, 2012, 08:11
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Are you sure you enclosed your cube within a cylindrical surface? Cannot see it in the image you attached…
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Old   April 16, 2012, 08:31
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Quote:
Originally Posted by lovecraft22 View Post
Are you sure you enclosed your cube within a cylindrical surface? Cannot see it in the image you attached…
SnappyHexMeshDict::
************************************************** *************
geometry
{
mvCube.stl
{
type triSurfaceMesh;
name mvCube;
}

cylinder1 //This cylinder is used.
{
type searchableCylinder;
point1 (100 50 0);
point2 (100 50 10);
radius 30;
}
}
castellatedMeshControls::
refinementSurfaces
{ mvCube
{
level (2 4);
}

}
refinementRegions
{

cylinder1
{
mode inside;
levels ((1e+15 2));
}
}

***************************************
This is what was used.
When you say covering the cube with cylinder. I am interpreting the one implimented.
But if you differ from this implementation. How to go about it ? (enclosed your cube within a cylindrical surface)

Regards
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Old   April 16, 2012, 08:40
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@Lore
Were you talking about this cylinder in the image attached. Now i could see it.
The patch you mentioned in your previous reply, stuck me now after your reply.
Is it correct now?

regards
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File Type: png snap_mvCube-2.png (9.7 KB, 49 views)
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Old   April 16, 2012, 08:48
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Yes, should be ok now. I'm running a similar case, I'll enclose it here in case you wanted to have a look. Unfortunately I'm struggling with it because it keeps blowing up… anyway the setup should be ok.
My cube is called cubo.stl and my cylinder is called cylinder.stl.

Refer to the allRun file for the commands I ran.
Attached Files
File Type: zip 2_cubo.zip (35.6 KB, 41 views)
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Old   April 17, 2012, 03:30
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@lore
Correct man, it is blowing up.

Help man. But do not know why?

Regards

/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 2.1.0-0bc225064152
Exec : pimpleDyMFoam
Date : Apr 17 2012
Time : 12:34:13
Host :
PID : 26986
Case pen-foam/mvCube
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0

Selecting dynamicFvMesh solidBodyMotionFvMesh
Selecting solid-body motion function rotatingMotion
Applying solid body motion to cellZone cylinder1
#0 Foam::error:rintStack(Foam::Ostream&) in "/opt/openfoam210/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1 Foam::sigSegv::sigHandler(int) in "/opt/openfoam210/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2 in "/lib/libc.so.6"
#3 Foam::solidBodyMotionFvMesh::solidBodyMotionFvMesh (Foam::IOobject const&) in "/opt/openfoam210/platforms/linux64GccDPOpt/lib/libdynamicFvMesh.so"
#4 Foam::dynamicFvMesh::addIOobjectConstructorToTable <Foam::solidBodyMotionFvMesh>::New(Foam::IOobjec t const&) in "/opt/openfoam210/platforms/linux64GccDPOpt/lib/libdynamicFvMesh.so"
#5 Foam::dynamicFvMesh::New(Foam::IOobject const&) in "/opt/openfoam210/platforms/linux64GccDPOpt/lib/libdynamicFvMesh.so"
#6
in "/opt/openfoam210/platforms/linux64GccDPOpt/bin/pimpleDyMFoam"
#7 __libc_start_main in "/lib/libc.so.6"
#8
in "/opt/openfoam210/platforms/linux64GccDPOpt/bin/pimpleDyMFoam"
Segmentation fault
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Old   April 17, 2012, 04:41
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Don't know… is your setup the same as mine?
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Old   April 17, 2012, 05:16
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@lore
My setup was not same as your will try again.
Why pimpleDyFoam is so challenging to implement
Also looking at the thesis mentioned in this thread. (How to simulate problems with rotating motion)

@lore
Should we also explore AMI feature , which i suppose should be implimented, as GGi is no longer present in
OpenFoam-210.
Do not know if atall these two things are related to this case, we are solving.
In propeller tutorial saw some commands in Allrun.pre which we have not implemented.
Could be because of that solver is crashing.

regards

Last edited by kid; April 17, 2012 at 06:56. Reason: missing thoughts
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Old   April 17, 2012, 17:28
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Hi, seems like my setup was wrong.

Have a look here:
pimpleDyMfoam simulation keeps blowing up

and especially here:
pimpleDyMfoam simulation keeps blowing up

Sorry about that…
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Old   April 18, 2012, 00:41
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@Lore
Seeing that discussion in a flash. This is cool man, need to put lot of effort
from my side.

Thanks a lot and great guiding line , now it feels this is right track.
Would work now and let you know the status soon.

regards
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