[FrancescaMangani]

Hi everybody,


I would like to understand if it is possible to add layers on a surface which is internal to the mesh.
Infact I'm doing a mesh in order to use chtMultiRegionFoam, splitting it with splitMeshRegions.
Therefore my boundaries are those of the block produced by the blockMesh, but I would like to add layers on the surface of my object, which is cointained in this block.


I would be really grateful to those who can give me any hint!

[SBreen]

Greetings,

I have the same problem, did you find a solution?

Thank you very much!

[SBreen]

Nevermind I found the solution.

You can use the region0_to_region1 patches. So for example if you have the regions heater and air you can use heater_to_air as a patch for addLayers.

[julieng]

Hello,

I try to mesh the interface between 2 regions with sHM.
I try to do your way. But snappy told me that the interface fluid_to_solid is not defined in the log file.

I tried to mesh only castellation and snap first, do a
splitMeshRegions -cellZones -overwrite
And mesh layers after that with no success.

I see on the forum that one solution is to copy paste each mesh obtained with castellation and snap = true and mesh it again in constant/polymesh with layers = true. Repeat it for each regions.
It is not very attractive, is there a more trivial way to do this?

Best regards

[SBreen]

Hello,

I think you might have used the wrong patch name in your layers definition. I used the name of the patch interface between the fluid and solid region. Try looking up the name in paraview maybe.

Hope i could help you and have nice holidays.

[julieng]

Hello,

Thank you for your answer. I am stuck since severals days on this.

Why don't you use the standard refinementSurface ? You don't specify faceZone and faceZone?

 refinementSurfaces
    {
        solid
        {
            // Surface-wise min and max refinement level
            level (2 2);
             regions
            {
                solid_fluid 
                  {
                  level (3 3);
                  }
            }
            faceZone solid; //insideFaces
            cellZone solid; //insideZone
            cellZoneInside inside;
          
         }  
         
          fluid
        {
            // Surface-wise min and max refinement level
            level (0 0);
            faceZone fluid;//insideFaces
            cellZone fluid; //outsideZone
            cellZoneInside inside;
        
         }

Why don't you snap the surfaces? Maybe you have only straight lines and 90° corners.
In my case I have a curved interface between solid and fluid regions, so I need to snap. I use the correct patch name fluid_to solid (patch name that it would be created with the splitMeshRegions -cellZones command.

addLayersControls
{
    relativeSizes false;

    // Per final patch (so not geometry!) the layer information
    layers
    {
        fluid_to_solid
            {
            nSurfaceLayers 6;
            finalLayerThickness 1.05;
            }
            
          wall
        {
        nSurfaceLayers 6;
        finalLayerThickness 1.05;
        }
    }

The patch wall is layered but not the interface between solid and fluid.
It seems that the mesh at the interface is not conform. The stl files are generated with Salome and are watertight and conform.

Originally Posted by julieng

Hello,

Thank you for your answer. I am stuck since severals days on this.

Why don't you use the standard refinementSurface ? You don't specify faceZone and faceZone?

 refinementSurfaces
    {
        solid
        {
            // Surface-wise min and max refinement level
            level (2 2);
             regions
            {
                solid_fluid 
                  {
                  level (3 3);
                  }
            }
            faceZone solid; //insideFaces
            cellZone solid; //insideZone
            cellZoneInside inside;
          
         }  
         
          fluid
        {
            // Surface-wise min and max refinement level
            level (0 0);
            faceZone fluid;//insideFaces
            cellZone fluid; //outsideZone
            cellZoneInside inside;
        
         }

Why don't you snap the surfaces? Maybe you have only straight lines and 90° corners.
In my case I have a curved interface between solid and fluid regions, so I need to snap. I use the correct patch name fluid_to solid (patch name that it would be created with the splitMeshRegions -cellZones command.

addLayersControls
{
    relativeSizes false;

    // Per final patch (so not geometry!) the layer information
    layers
    {
        fluid_to_solid
            {
            nSurfaceLayers 6;
            finalLayerThickness 1.05;
            }
            
          wall
        {
        nSurfaceLayers 6;
        finalLayerThickness 1.05;
        }
    }

The patch wall is layered but not the interface between solid and fluid.
It seems that the mesh at the interface is not conform. The stl files are generated with Salome and are watertight and conform.



Maybe add layers on a curved interface in not an easy task.

Have a nice Christmas

Julien

Maybe add layers on a curved interface in not an easy task.

Have a nice Christmas

Julien

[julieng]

This is the mesh after addlayers operation



No layers added at the interface...

[julieng]

Hello,

I found this post very close of mine.
Trouble with snappy and boundary layers

As in your example it is used a typo like this one to define the location in mesh without faceZone, cellZone, cellZoneInside, features

locationsInMesh
(
((1.4 0.05 0.05) fluid)
((1.6 0.05 0.05) solid)
);

The problem is that I have an error when I try this way:

--> FOAM FATAL IO ERROR:
keyword locationInMesh is undefined in dictionary "C:/PROGRA~1/BLUECF~1/OFUSER~1/run/SNAPPY~1/CHCD7B~1/system/snappyHexMeshDict.castellatedMeshControls"

file: C:/PROGRA~1/BLUECF~1/OFUSER~1/run/SNAPPY~1/CHCD7B~1/system/snappyHexMeshDict.castellatedMeshControls from line 98 to line 271.

    From function const Foam::entry& Foam::dictionary::lookupEntry(const Foam::word&, bool, bool) const
    in file db/dictionary/dictionary.C at line 566.

FOAM exiting

Maybe my version of OpenFoam is out of date to support this typo?
bluecfdcore Openfoam 5.

What do you think?

Julien

[julieng]

I see that this function is not implemented in the Openfoam fundation versions !!

Multiple meshed components missing

Is there a possibility toadd layers at the interface solid-fluid with the foundation version of Openfoam ?

[dlahaye]

Does the extrudeMesh utility helps here?

[julieng]

Hello,

Thank you for your answer. I am looking for a "standard" procedure being able to mesh every cases I will test. Not only this geometry.

Best regards

[julieng]

Can anyone tell me what is wrong with my typo of layer section, for calling the interface between fluid and solid in my snappyHexMeshDict file?

[julieng]

Ok, the solution was to do the operation:
splitMeshRegions -cellZones -overwrite

And after that it is possible to create BL at the interface

[CFD_Freiberg]

Originally Posted by julieng

Ok, the solution was to do the operation:
splitMeshRegions -cellZones -overwrite

And after that it is possible to create BL at the interface

Hello julieng,
nice to hear you could solve the problem.
Could you sum up the successful workflow?


Because i'm in the same position like you at the beginning and i followed your steps but still can't get layers at the interface area.


Here's my workflow.
1. use sHM with castellatedMesh and snap both "true", addLayers is "false"
2. use "splitMeshRegions -cellZones -overwrite"
3. use sHM with castellatedMesh and snap both "false" and addLayers "true"


but there're still no layers at the interface. I'm using OpenFoam 8.



With kind regards
Christian

[Mfebbo]

I am having same issue and still no success copying files from fluid region to contact/polymesh and setting addlayers to true and the other two to false. I have given the right name of the created interface patch to the addlayercontrols section of snappyhexmesh, but still nothing. Someone could explain the right steps to solve it? Many thanks

[aendres]

Hi,

this is a workflow, which worked for me in OpenFoam 9:

blockMesh

foamDictionary -entry "castellatedMesh" -set "true" system/snappyHexMeshDict
foamDictionary -entry "snap" -set "true" system/snappyHexMeshDict
foamDictionary -entry "addLayers" -set "false" system/snappyHexMeshDict
snappyHexMesh -overwrite

splitMeshRegions -cellZones -overwrite

rm -r constant/polyMesh

foamDictionary -entry "castellatedMesh" -set "false" system/snappyHexMeshDict
foamDictionary -entry "snap" -set "false" system/snappyHexMeshDict
foamDictionary -entry "addLayers" -set "true" system/snappyHexMeshDict

echo 'snappyHexMesh: coolant layers'
mv constant/coolant/polyMesh constant
snappyHexMesh -overwrite
mv constant/polyMesh constant/coolant

echo 'snappyHexMesh: metal layers'
mv constant/metal/polyMesh constant
snappyHexMesh -overwrite
mv constant/polyMesh constant/metal

The case I used was an altered 'heatedDuct' tutorial case with only two regions: coolant and metal. splitMeshRegions creates the two patches metal_to_coolant and coolant_to_metal, which is why I put the following layer definition in system/snappyHexMeshDict:

addLayersControls
{
    relativeSizes   true;
    minThickness    1e-10;
    finalLayerThickness 0.67;
    expansionRatio  1.5;
    layers
    {
        metal_to_coolant
        {
            nSurfaceLayers  2;
        }
        coolant_to_metal
        {
            nSurfaceLayers  2;
        }
    }
}