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boundary condition for zerothickness surface :(

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Old   April 28, 2015, 12:58
Default boundary condition for zerothickness surface :(
  #1
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Naresh Yathuru
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Hi Foamers,

I have a case with zero thickness sucface inside my domain. I innitially thought that i need to have createBafflesDict then i came to know that i can create baffles using STL files in the snappyHexMesh. thanks to SHM.

Now i m kind of stuck trying to set booundary conditions for the master and slave patches ,where to specify the B.C?

can somebody please help me.

Code:
// Which of the steps to run
castellatedMesh true;    // make basic mesh ?
snap            true;    // decide to snap back to surface ?
addLayers       false;   // decide to add viscous layers ?


geometry // Load in STL files here
{       
    /*baffle
    {
        type searchablePlate;
        origin (2.4 1.8 0.8);
        span (1.2 2.7 0.8);
         regions
        {
            region0
            {
               name  baffle;
            }
        }
    }*/
               
    inlet.stl {type triSurfaceMesh; name inlet;}
    outlet.stl {type triSurfaceMesh; name outlet;}
    heater.stl {type triSurfaceMesh; name heater;}
    roomwall.stl {type triSurfaceMesh; name roomwall;}
        roof.stl {type triSurfaceMesh; name roof;}
        floor.stl {type triSurfaceMesh; name floor;}
        window.stl {type triSurfaceMesh; name window;}
        table.stl {type triSurfaceMesh; name table;}
        man1.stl {type triSurfaceMesh; name man1;}
        man2new.stl {type triSurfaceMesh; name man2new;}
    //fullgeomnew.stl {type triSurfaceMesh; name fullgeomnew;}
        //mergedwithouttable.stl {type triSurfaceMesh; name mergedwithouttable;}
    //refinementBox {type searchableBox; min (-2 -2 6); max (7 5 -2);}
};

castellatedMeshControls
{
    maxLocalCells 500000;  //max cells per CPU core
    maxGlobalCells 4000000; //max cells to use before mesh deletion step
    minRefinementCells 10;  //was 0 - zero means no bad cells are allowed during refinement stages
    maxLoadUnbalance 0.10;
    nCellsBetweenLevels 3;  // expansion factor between each high & low refinement zone

    // Explicit feature edge refinement
    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    features // taken from STL from each .eMesh file created by "SurfaceFeatureExtract" command
    (
       {file "inlet.eMesh"; level 5;} 
        {file "outlet.eMesh"; level 3;} 
        {file "roomwall.eMesh"; level 3;} 
        {file "heater.eMesh"; level 2;}
        {file "roof.eMesh"; level 1;}  
        {file "floor.eMesh"; level 2;}
        {file "window.eMesh"; level 3;}
        {file "table.eMesh"; level 3;}
        {file "man1.eMesh"; level 2;}
        {file "man2new.eMesh"; level 3;}
        //{file "mergedwithouttable.eMesh"; level 3;} 
    );

    // Surface based refinement
    // ~~~~~~~~~~~~~~~~~~~~~~~~

    refinementSurfaces // Surface-wise min and max refinement level
    {
    inlet {
        level (5 5);//faceZone inlet;cellZone inlet;cellZoneInside inside;
        } // was 0 0
        outlet {
         level (3 3);//faceZone outlet;cellZone outlet;cellZoneInside inside;
         }
    roomwall {
        level (3 3);//faceZone roomwall;cellZone roomwall;cellZoneInside inside;
        }  //was 3 3
    heater {
        level (2 2);//faceZone heater;cellZone heater;cellZoneInside inside;
        } // was 4 4
        roof {
        level (2 2);///faceZone roof;cellZone roof;cellZoneInside inside;
         }
        floor {
        level (2 2);//faceZone floor;cellZone floor;cellZoneInside inside;
        }
        window {
        level (3 3);//faceZone window;cellZone window;cellZoneInside inside;
        }
        //table {
        //level (0 0);//faceZone table;cellZone table;cellZoneInside inside;
        //}
        man1 {
        level (3 3);//faceZone man1;cellZone man1;cellZoneInside inside;
        }
        man2new {
        level (3 3);//faceZone  man2;cellZone man2;cellZoneInside inside;
        }
        //baffle {level (3 3);}
        table
        {
        level (3 3);
        faceZone table;

        // Create baffles for all faces on the surface
        faceType baffle;

        cellZone table;
        cellZoneInside inside;
        }  
        
        
    }  


    resolveFeatureAngle 30;  // (before 80) .Resolve sharp angles // Default 30
    //refinementRegions        // In descending levels of fine-ness
    //{fullgeomnew //{mode inside;levels ((0.3 3));}}      //error: shell mergedtest is suitable for inside mode.
    
     //{mode distance; levels ((0.01 4) (0.03 3) (0.1 2));}} // was ((0.001 4) (0.003 3) (0.01 2))
     //when i tried like this 
    refinementRegions{}
    
     //the whole geometry is meshed and the cell are not removed.*/
    locationInMesh (1 1 1);  //to decide which side of mesh to keep **
    allowFreeStandingZoneFaces true; // before true
}


// Settings for the snapping.
snapControls
{
    nSmoothPatch 5;// before 3
    tolerance 1.0; // before 2
    nSolveIter 50;// before 30
    nRelaxIter 10; //before 5
    nFeatureSnapIter 25; // default is 10
    
// New settings from openfoam 2.2 onwards for SHMesh

implicitFeatureSnap false; // default is false - detects without doing surfaceFeatureExtract
explicitFeatureSnap true; // default is true
multiRegionFeatureSnap true; // deafault is false - detects features between multiple surfaces

}
I m using buoyantBoussinessqsimpleFoam solver. As a first step i m intended to implement a no-slip U(0,0,0) B.c

I have looked into some tutorials but each tutorials has a different style of implementing the baffles. so i could not able to find it myself.
I m desperate for help.
Thank you ,

regards,
Naresh
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Old   April 30, 2015, 12:40
Default
  #2
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Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 8,301
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wyldckat is just really nicewyldckat is just really nicewyldckat is just really nicewyldckat is just really nice
Quick answer: Study the tutorial cases "compressible/rhoPimpleDyMFoam/annularThermalMixer" and "incompressible/pimpleFoam/TJunctionFan".
Hints:
  • The first one demonstrates how to create the baffles.
  • The second one demonstrates how to define the boundary conditions while it's creating the baffles.
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Old   May 4, 2015, 04:26
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Naresh Yathuru
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Dear Bruno,
Thank you for your reply. I will check it out.

Regards,
Naresh Yathuru
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