[heo]

hi everyone!

I am implementing a piston motion using a foam-extend version.

I tried to use the existing openfoam 4.1 version of ACMI, but as the piston moves, the grid deforms, so I use the foam-extend version of the ggi.

However, despite using ggi, if you look at the attached picture, you can see that the grid at the top of the domain is deformed as the piston moves.

For dynamicmesh, dynamicInkJetFvMesh was used, and the boundary area between the piston and the domain was set to ggi.

How do I avoid grid deformation at the top of the domain?


polyMesh/boundary

 Wedge1
    {
        type            empty;
        nFaces          1100;
        startFace       13148;
    }
    Piston
    {
        type            wall;
        inGroups        1(wall);
        nFaces          50;
        startFace       14248;
    }
    Wedge3
    {
        type            empty;
        nFaces          1100;
        startFace       14298;
    }
    SlipWall
    {
        type            wall;
        inGroups        1(wall);
        nFaces          44;
        startFace       15398;
    }
    Piston_out
    {
        type            ggi;
        nFaces          50;
        startFace       15442;
	shadowPatch	Domain_in;
	zone		pzone;
	bridgeOverlap	true;

    }
    Wedge1
    {
        type            empty;
        nFaces          5600;
        startFace       15492;
    }
    Wedge2
    {
        type            empty;
        nFaces          5600;
        startFace       21092;
    }
    Wall
    {
        type            wall;
        inGroups        1(wall);
        nFaces          40;
        startFace       26692;
    }
    FarField
    {
        type            patch;
        nFaces          50;
        startFace       26732;
    }
    Ypiston
    {
        type            patch;
        nFaces          40;
        startFace       26782;
    }
    SlipWall2_Inlet
    {
        type            wall;
        inGroups        1(wall);
        nFaces          90;
        startFace       26822;
    }
    SlipWall2_Outlet
    {
        type            patch;
        nFaces          90;
        startFace       26912;
    }
    Domain_in
    {
        type            ggi;
        nFaces          50;
        startFace       27002;
	shadowPatch	Piston_out;
	zone		dzone;
	bridgeOverlap	true;
    }
)