[Lundby]

Currently, I am working on an overset mesh as part of a fluid-structure interaction (FSI) simulation using preCICE to couple OpenFOAM and Calculix. The boundaries of my overset mesh are successfully deforming in sync with the moving flap. However, I am encountering issues with the movement of the interior cells in the overset mesh; they are not behaving as expected.

I am uncertain if this issue stems from the boundary conditions or potentially an error in how I have defined my dynamicMeshDict file. I have included a link to a video that demonstrates the issue I am facing: https://www.youtube.com/watch?v=vroELwhxOic. As you can see, the first cell inside the overset mesh is not behaving as it should, and I am seeking advice on how to resolve this problem.

My dynamicMeshDict looks like this:

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      dynamicMeshDict;
}

//dynamicFvMesh staticFvMesh;
dynamicFvMesh       dynamicOversetFvMesh;
//solver        multiSolidBodyMotionSolver;


motionSolverLibs ("libfvMotionSolvers.so");


solver    displacementLaplacian;

displacementLaplacianCoeffs
{
	diffusivity inverseDistance (overset1);
	diffusivity inverseDistance (overset);
}

And my pointDisplacement looks like this:

FoamFile
{
    version     2.0;
    format      ascii;
    class       pointVectorField;
    object      pointDisplacement;
}

dimensions      [0 1 0 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{


    overset
    {
        patchType       overset;
        type            fixedValue;
    }
    
    overset1
    {
        type            fixedValue;
        value           $internalField;
    }
    
    walls
    {
        type            uniformFixedValue;
        uniformValue    (0 0 0);
    }
    
    inlet
    {
        type            uniformFixedValue;
        uniformValue    (0 0 0);
    }
    
   
    outlet
    {
        type            uniformFixedValue;
        uniformValue    (0 0 0);
    }
    
    lowerWall
    {
        type            uniformFixedValue;
        uniformValue    (0 0 0);
    }
    

    flap
    {
        type            fixedValue;
        value           $internalField;
    }

}

[xiangxiang]

Hi, Lundby
Have you solved this problem?
I encountered the same problem when using overset grids.

[Umut]

Hello,

I'm also facing the same problem.

Any update or solution?

[Lundby]

Yes, https://www.youtube.com/watch?v=8GoG1gxc8lo
Also included contact mechanics

[Umut]

Dear Lundby,

Thank you for sharing the video of your FSI work.

I got to notice that in older OF versions (at least v2206 and older), overset boundary follows the deforming solid (deforms with it). For example in your video (Turek-Hron benchmark) the mesh around the elastic plate and its overset boundary deforms with the plate.

In more recent OF versions I couldn't manage to deform the overset type boundary. Please kindly check the question I asked in this link:

Front mesh boundaries (overset patch) not deforming on newer OF releases

I also watched your FSI contact video (U field), I noticed there is a vibration in the whole domain in the second half of the video. I have a feeling that it is caused by dynamic mesh selections and if you visualize mesh motion it might be vibrating for no good reason. Is that the case?

[Pablo34]

Originally Posted by Lundby

Yes, https://www.youtube.com/watch?v=8GoG1gxc8lo
Also included contact mechanics

Dear Lundby,

Thanks for your post. It looks really nice. If possible, could you please share the files of the simulation? Thanks in advance.