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-   -   select disk with faceSet (http://www.cfd-online.com/Forums/openfoam-pre-processing/102972-select-disk-faceset.html)

raffale June 7, 2012 10:20

select disk with faceSet
 
Hi everyone,

This is my first thread but I already spent a lot of time to read yours threads. This forum is a blessing for every new user of Openfoam like me.

So this is my case, I want to simulate the landing of an helicopter in aerodynamic corridor disrupted by structures. I chose to model the rotors with actuator disks.

I used snappyHexMesh for create my Mesh (helicoptere without rotors + ground structures) and I use toposet and createBaffles to create my rotors. Then I use type fan BC for my rotors.

My problem: In my toposet I only know create rectangular:mad: rotor with these lines:
actions
(
{
name cyclicfanFaces;
type faceSet;
action new;
source boxToFace;
sourceInfo
{
box (13 -1.5 9.4) (16 1.5 9.6);
}
}

{
name cyclicfanFacesSlaveCells;
type cellSet;
action new;
source boxToCell;
sourceInfo
{
box (13 -1.5 9.5) (16 1.5 13);
}
}

{
name cyclicfanZoneFaces;
type faceZoneSet;
action new;
source setsToFaceZone;
sourceInfo
{
faceSet cyclicfanFaces;
cellSet cyclicfanFacesSlaveCells;
}
}


);

// ************************************************** *********************** //


And I Want to select a DISK rotor, because a rotor is a disk:D. I think this problem is boxToFace in faceSet but I don't know what other faceSet keyword choose.
With CellSet we can use cylinderToCell but with faceSet it's not possible.

So have you suggestions to solve that simple but annoying problem.

Thanks ahead for your comments
Regards,
Cyril

PS: Don't hesitate to correct my english. I must improve my writing skills;).

anon_a June 7, 2012 11:08

If you take a look in

applications/utilities/mesh/manipulation/topoSet/topoSetDict

you can see various functions that you can use to select cells/faces/points.
Something that you could do perhaps is a cylinderToCell to select cells on both sides of the wanted faces and then cellToFace with the option "both".

Assuming off course that your faces are appropriately shaped and positioned to create a perfect disk.

raffale June 7, 2012 15:24

Thanks for your reply anon_a, I'll take a look tomorrow.

After reading the post on the forum and after taking a look on the tutorial with "type fan BC"(Tjunctionfan), I found it strange that in these cases the actuator disk was modeled by a rectangular surface and never with disk.

What a pity that cylinderToFace doesn't exist in OpenFoam. This would be so much easier.

Regards,
Cyril

gschaider June 7, 2012 17:37

Quote:

Originally Posted by raffale (Post 365325)
Thanks for your reply anon_a, I'll take a look tomorrow.

After reading the post on the forum and after taking a look on the tutorial with "type fan BC"(Tjunctionfan), I found it strange that in these cases the actuator disk was modeled by a rectangular surface and never with disk.

What a pity that cylinderToFace doesn't exist in OpenFoam. This would be so much easier.

Regards,
Cyril

At least you can spare yourself the trouble of programming your own topoSource with the expressionToFace topo-source that comes with swak4Foam. Something like

expression "mag(pos().z)<1 && sqrt(pow(pos().x,2)+ pow(pos().y,2))<1"

will select all faces on the boundary of a cylinder

expression "mag(fpos().z)<1 && sqrt(pow(fpos().x,2)+ pow(fpos().y,2))<1"

will select all faces INSIDE the cylinder

raffale June 8, 2012 08:27

It works! Thanks for yours replies, it was helpful.

Here is my toposet if someone want to select a disk:



/*--------------------------------*- C++ -*----------------------------------*\

| ========= | |

| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |

| \\ / O peration | Version: 2.0.1 |

| \\ / A nd | Web: www.OpenFOAM.com |

| \\/ M anipulation | |

\*---------------------------------------------------------------------------*/

FoamFile

{

version 2.0;

format ascii;

class dictionary;

object topoSetDict;

}



// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //



actions

(

{

name c0;

type cellSet;

action new;

source cylinderToCell;

sourceInfo

{

//box (12.5 -2 9.5) (16 2 13);

p1 (14.5 0 9);

p2 (14.5 0 11);

radius 3.4;

}

}



{

name cyclicfanFaces;

type faceSet;

action new;

source cellToFace;

sourceInfo

{

set c0;

option both;

}

}



{

name c1;

type cellSet;

action new;

source cylinderToCell;

sourceInfo

{

//box (12.5 -2 9.5) (16 2 13);

p1 (14.5 0 10);

p2 (14.5 0 11);

radius 3.4;

}

}



{

name f1;

type faceSet;

action new;

source cellToFace;

sourceInfo

{

set c1;

option both;

}

}



{

name c2;

type cellSet;

action new;

source cylinderToCell;

sourceInfo

{

//box (12.5 -2 9.5) (16 2 13);

p1 (14.5 0 9);

p2 (14.5 0 10);

radius 3.4;

}

}



{

name f2;

type faceSet;

action new;

source cellToFace;

sourceInfo

{

set c2;

option both;

}

}



{

name cyclicfanFaces;

type faceSet;

action delete;

source faceToFace;

sourceInfo

{

set f1;

}

}



{

name cyclicfanFaces;

type faceSet;

action delete;

source faceToFace;

sourceInfo

{

set f2;

}

}

It's a succession of boolean operations.


Regards,
Cyril


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