[Jamill1283]

Dear Foamers,

I'm facing an issue with a multiphase flow simulation that involves modeling a liquid ligament in air. The geometry of the ligament, which is custom-designed using CAD software, has been exported to an STL file for this purpose.

My objective is to simulate this specific geometry in a 2D axisymmetric manner. However, I'm encountering a problem when the simulation is set up with a 2D mesh (having a mesh count of 1 in the z-direction); the liquid phase, which has a volume fraction of 1, does not appear correctly in the simulation. Interestingly, when I increase the mesh count in the z-direction to a higher number, the liquid's shape is accurately represented.

My blockmesh is as below;

scale 0.001;

blockWidth #eval "3";
ligamentSize #eval "0.5";
theta #eval "45.0 / 8";

arcLocZ #eval "($blockWidth) * sin(degToRad($theta))";
arcLocY #eval "($blockWidth) * cos(degToRad($theta))";
nArcLocZ #eval "-1*$arcLocZ";
ligArcLocZ #eval "($ligamentSize) * sin(degToRad($theta))";
ligArcLocY #eval "($ligamentSize) * cos(degToRad($theta))";

smallArcLocZ #eval "($blockWidth) * sin(degToRad($theta/2))";
smallArcLocY #eval "($blockWidth) * cos(degToRad($theta/2))";
smallLigArcLocZ #eval "($ligamentSize) * sin(degToRad($theta/2))";
smallLigArcLocY #eval "($ligamentSize) * cos(degToRad($theta/2))";

vertices
(
    (0  0 0) 
    (10 0 0) 
    (10 $blockWidth 0) 
    (0  $blockWidth 0) 
    (0 $arcLocY $arcLocZ)
    (10 $arcLocY $arcLocZ)
);

blocks
(
    hex (0 3 4 0 1 2 5 1) (100 100 1) simpleGrading (1 1 1) //the issue is here
);

edges
(
);

patches
(
    patch outlet
    (
        (2 5 1 1)
    )    
);

boundary
(
    front
    {
        type wedge;
        faces
        (
            (0 1 5 4)
            (0 1 2 3)
        );
    }
    ligament
    {
        type symmetry;
        faces
        (
            (3 4 0 0)
        );
    }
    external
    {
        type wall;
        faces
        (
            (3 4 5 2)
        );
    }
    axis
    {
        type  empty;
        faces
        (
            (0 1 1 0)
        );
    }
);

mergePatchPairs
(
);

Setfields as below;

defaultFieldValues
(
    volScalarFieldValue alpha.phase1 0
    volVectorFieldValue U (0 0 0)
);


regions (
   surfaceToCell {
   file           "./constant/fluidStruct/ligament108.stl";
   outsidePoints  ((0.008 0.00025 0));
   includeInside  true;
   includeOutside false;
   includeCut     true;
   nearDistance   -1;
   curvature      -100;
   fieldValues (
   volScalarFieldValue alpha.phase1 1
  );
 }
);

I'm seeking advice or solutions to ensure that the liquid phase is properly visualized while maintaining the simulation in a strictly 2D axisymmetric setup. Any insights or suggestions would be greatly appreciated.

Attached are visuals for 3D, problem for 2D mesh and zipped STL files;
Screenshot from 2024-03-12 14-29-41.png

Screenshot from 2024-03-12 14-20-39.png

ligament.zip

Thank you in advance for your assistance.
Jamil