[me12p1006]

Hi,

I would like to create 1cm circular air inlet on 4cm by 4cm square face that is treated as a wall.

I would like to use patching in openFoam. Can anyone help me with this.

[clapointe]

I've selected cells within a cylinder using cylinderToCells in conjunction with topoSet before. It looks like topoSet also has a cellToFace option -- please see this link https://github.com/OpenFOAM/OpenFOAM...em/topoSetDict. Combining these should give you what you're looking for.

Caelan

[me12p1006]

Originally Posted by clapointe

I've selected cells within a cylinder using cylinderToCells in conjunction with topoSet before. It looks like topoSet also has a cellToFace option -- please see this link https://github.com/OpenFOAM/OpenFOAM...em/topoSetDict. Combining these should give you what you're looking for.

Caelan

Thanks for your reply. I tried using it. But i couldn't get flow through the inlet when I gave velocity inlet boundary condition. Here are the files of my toposet and createpatchdict.

Toposet:
actions
(
{
name z;
type cellSet;
action new;
source boxToCell;
sourceInfo
{
box (-100 -100 -0.2)(100 100 100);
}
}

{
name bubble;
type faceSet;
action new;
source cellToFace;
sourceInfo
{
set z;
option all;
}
}

{
name z;
type cellSet;
action invert;
}

{
name bubble;
type faceSet;
action subset;
source cellToFace;
sourceInfo
{
set z;
option all;
}
}

Createpatchdict:

patches
(
{
//- name of new patch
name inlet;

//- type of new patch
patchInfo
{
type patch;
}
//- How to construct: either from 'patches' or 'set'
constructFrom set;
//- if constructionFrom = set : name of faceSet
set bubble;
}
);

I the boundary conditions file I used "inlet" as the name and then i defined my boundary conditions.

I ran the following commands and i couldnt find any error. But, I couldnt get flow through the inlet.

blockMesh
topoSet
createPatch -overWrite
setFields
interFoam

[clapointe]

Starting with a square inlet might be a good first step -- this can be done using topoSet's boxToFace and then createPatch. Check out this fireFoam tutorial : https://github.com/OpenFOAM/OpenFOAM...mallPoolFire3D.

Caelan

[luther1990]

Well, if you want some perfect circular mesh instead of zigzag mesh, you might want to use snappyHexMesh. You need to split the stl file into two parts.

[me12p1006]

Originally Posted by clapointe

Starting with a square inlet might be a good first step -- this can be done using topoSet's boxToFace and then createPatch. Check out this fireFoam tutorial : https://github.com/OpenFOAM/OpenFOAM...mallPoolFire3D.

Caelan

Thanks. I could able to create square inlet using toposets boxtoface and createpatch. But how can I do for circular inlet.

[luther1990]

Originally Posted by me12p1006

Thanks. I could able to create square inlet using toposets boxtoface and createpatch. But how can I do for circular inlet.

Please refer to

tutorials/incompressible/simpleFoam/rotorDisk/system/snappyHexMeshDict

1. You can create a surface mesh like stl and obj using a thirty-party tool like Blender. The shape of the surface mesh can be a plane.
   
2. Split the surface mesh into two parts, with a circular part in the middle.
   
3. Use similar snappyHexMeshDict in rotorDisk case to create the circular inlet boundary and the surrounding wall boundary.
   
4. Besides, you must use surfaceFeatureExtractDict to keep the circular features.

Remeber, you only need to use the plane to cut the domain and generate the inlet boundary.

[clapointe]

Hi All,

I've recently revisited this problem. You can create the inlet by first creating a cylindrical faceZoneSet then converting it to a faceSet. If you start with hex cells this will preserve your hex cells while getting you a mostly circular inlet. The inlet will get more and more circular as your mesh resolution increases.

Caelan

[Peruni]

Hi, If someone is still struggling with this problem what you need to do in order to obtain circular patch is:
1). create cellset using cylinderToCell option
2) create faceSet based on coolingSet
3) use faceSet action - subset - source - boxtoFace to choose only external faces of cells.




Hope it helped.

[JoshWilliams1996]

If you have your blockMesh you should be able to take a slice from the wall and change it into another patch, the new inlet, using topoSet and createPatch. I realise you have done this above so I have attached some code I used if this helps. Maybe the problem is where you use setFields, everything else sounds fine.

I would use topoSet to define a cylinder that overlaps the cells you want to become your inlet, then you get all faces in this cellSet. From here you can find the faces in your newly defined faceSet which intersect with your wall patch. Finally you remove the initial cellSet to keep things tidy.

    {
        name    i1;
        type    cellSet;
        action  new;
        source cylinderToCell;
        sourceInfo
	{
       	    p1       (0.0165 -0.1375 -0.229); // start point on cylinder axis
       	    p2       (0.0130 -0.1365 -0.2330);   // end point on cylinder axis
       	    radius   5.0;
    	}
    }

    // Get all faces in cellSet
    {
        name    inlet1;
        type    faceSet;
        action  new;
        source  cellToFace;
        sourceInfo
        {
            set     i1;
            option  all;
        }
    }
    {
        name inlet1;
        type faceSet;
        action subset;
        source patchToFace;
        sourceInfo
        {
            name "walls";
        }
    }

    {
        name i1;
        type cellSet;
        action remove;
    }

Then you can use the createPatch function if you have a createPatchDict to declare your inlet from the set you just created above, like so

{
        // Name of new patch
        name inlet;

        // Dictionary to construct new patch from
        patchInfo
        {
            type patch;
        }

        // How to construct: either from 'patches' or 'set'
        constructFrom set;

        // If constructFrom = set : name of faceSet
        set inlet1;
    }

[Madeinspace]

Hi Josh,


I had been following this method and also followed the instruction your provided but I just can't seem to get it right. It does create a new circular patch but it doesn't contain all the cells within that radius as shown in the picture attached. Several cells are missing within the new patch. Would you have idea why is that?


my topoSetDict

actions
(
    {
        name    jetCells;
        type    cellSet;
        action  new;
      source cylinderToCell;
        sourceInfo
        {
            p1 (0.05    0.015    0);   // start point on cylinder axis//
            p2 (0.05    0.0148   0);   // end point on cylinder axis//
            radius 0.009;
        }
    }


{
        name    f0;
        type    faceSet;
        action  new;
        source  cellToFace;
        sourceInfo
        {
            set     jetCells;
            option  all;
        }
    }


{
        name    f0;
        type    faceSet;
        action  subset;
          source patchToFace;
     sourceInfo
     {
    name "topAtmosphere";
     }
}

    {
        name jetCells;
        type cellSet;
        action remove;
    }


);

my createPatchDict

pointSync true;

// Patches to create.
patches
(
    {
        name shieldGasInlet;

        // Type of new patch
        patchInfo
        {
            type patch;
        }

        // How to construct: either from 'patches' or 'set'
        constructFrom set;

        //constructFrom patches;

        // If constructFrom = patches : names of patches. Wildcards allowed.
        //patches ("periodic.*");

        // If constructFrom = set : name of faceSet
           set f0;
    }
);