[Fieschi]

Hello,

I am trying to model a plate with a -5 deg origin angle on z axis.
It is an overset 2D simulation using the sixDoFRigidBodyMotion solver in a domain with a fixed velocity in x-direction.
I use OpenFOAM V1706.

Domaine_6ddl.jpg

The blue block is my background (fixed block) and my object is inside a moving cylinder which is my overset (red).
The center of mass and center of rotation are at the same point : the plate's lower-left corner.

I would like to leave my object in a free motion so this is my dynamicMeshDict :

 FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      dynamicMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
motionSolverLibs ("libsixDoFRigidBodyMotion.so");

dynamicFvMesh       dynamicOversetFvMesh;

dynamicOversetFvMeshCoeffs
{
}

solver    sixDoFRigidBodyMotion;

sixDoFRigidBodyMotionCoeffs 
{
    patches         (object);
    innerDistance   100.0; 
    outerDistance   101.0; 

    centreOfMass    (0.0 0.0 0.125);

    // Cuboid dimensions
    Lx              1.0;
    Ly              0.1;
   Lz              ?;

    // Density of the solid
    rhoSolid        1000;

    // Cuboid mass
    mass           #calc "$rhoSolid*$Lx*$Ly*$Lz";
     
    momentOfInertia #codeStream
        {
        codeInclude
        #{
            #include "diagTensor.H"
        #};

        code
        #{
            scalar sqrLx = sqr($Lx);
            scalar sqrLy = sqr($Ly);
            scalar sqrLz = sqr($Lz);
            os  <<
                $mass
               *diagTensor(sqrLy + sqrLz, sqrLx + sqrLz, sqrLx + sqrLy)/12.0;
        #};
        };

    g               (0 -9.81 0);
    rho             rhoInf; 
    rhoInf          1; 
    report          on;
    reportToFile    on; 

    accelerationRelaxation 0.1;

    solver
    {
        type Newmark;
    }

        constraints 
        {
   
        fixedPoint
        {
             sixDoFRigidBodyMotionConstraint point;
             centreOfRotation (0.0 0.0 0.125);
        }
        
        fixedAxis
        {
            sixDoFRigidBodyMotionConstraint axis;
            axis (0 0 1);
        }
    
        }
}
// ************************************************************************* // 

Could you tell me which z dimension I have to take for cuboid dimensions ?
The domain's size in Z-direction (I have read this on an other post but it was to calculate force coefficient and I am not sure that it is the same thing) or 1 meter ?

Any help would be appreciated !
Regards

[Zhi Cheng]

Hi, have you understand the Z direction distance in the 2d sixdof, it seems it's related to the density, mass of the soild, which means the forces acting on the surface is different. Do you have knowledge about this?
ZHI CHENG

Originally Posted by Fieschi

Hello,

I am trying to model a plate with a -5 deg origin angle on z axis.
It is an overset 2D simulation using the sixDoFRigidBodyMotion solver in a domain with a fixed velocity in x-direction.
I use OpenFOAM V1706.

Attachment 59241

The blue block is my background (fixed block) and my object is inside a moving cylinder which is my overset (red).
The center of mass and center of rotation are at the same point : the plate's lower-left corner.

I would like to leave my object in a free motion so this is my dynamicMeshDict :

 FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      dynamicMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
motionSolverLibs ("libsixDoFRigidBodyMotion.so");

dynamicFvMesh       dynamicOversetFvMesh;

dynamicOversetFvMeshCoeffs
{
}

solver    sixDoFRigidBodyMotion;

sixDoFRigidBodyMotionCoeffs 
{
    patches         (object);
    innerDistance   100.0; 
    outerDistance   101.0; 

    centreOfMass    (0.0 0.0 0.125);

    // Cuboid dimensions
    Lx              1.0;
    Ly              0.1;
   Lz              ?;

    // Density of the solid
    rhoSolid        1000;

    // Cuboid mass
    mass           #calc "$rhoSolid*$Lx*$Ly*$Lz";
     
    momentOfInertia #codeStream
        {
        codeInclude
        #{
            #include "diagTensor.H"
        #};

        code
        #{
            scalar sqrLx = sqr($Lx);
            scalar sqrLy = sqr($Ly);
            scalar sqrLz = sqr($Lz);
            os  <<
                $mass
               *diagTensor(sqrLy + sqrLz, sqrLx + sqrLz, sqrLx + sqrLy)/12.0;
        #};
        };

    g               (0 -9.81 0);
    rho             rhoInf; 
    rhoInf          1; 
    report          on;
    reportToFile    on; 

    accelerationRelaxation 0.1;

    solver
    {
        type Newmark;
    }

        constraints 
        {
   
        fixedPoint
        {
             sixDoFRigidBodyMotionConstraint point;
             centreOfRotation (0.0 0.0 0.125);
        }
        
        fixedAxis
        {
            sixDoFRigidBodyMotionConstraint axis;
            axis (0 0 1);
        }
    
        }
}
// ************************************************************************* // 

Could you tell me which z dimension I have to take for cuboid dimensions ?
The domain's size in Z-direction (I have read this on an other post but it was to calculate force coefficient and I am not sure that it is the same thing) or 1 meter ?

Any help would be appreciated !
Regards