[Scabbard]

Originally Posted by Maimouna

Hi Scabbard,

of course, I need your help. I'm struggling on that for long time. If you don't mind please we can shear your idea and I would be really grateful.

My email address is: may78may@hotmail.com

Best regards
Maimouna

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.3.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      dynamicMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dynamicFvMesh      dynamicMotionSolverFvMesh;

motionSolverLibs ("libsixDoFRigidBodyMotion.so");

solver            sixDoFRigidBodyMotion;

sixDoFRigidBodyMotionCoeffs
{
    patches         (CYLINDER);
    innerDistance   1; // motion area
    outerDistance   2; // dynamic mesh area

    mass            9.97; // mass
    centreOfMass    (0 0 0.29);
    momentOfInertia (0.055 0.055 1);
    g               (0 0 -9.81);
    orientation
    (
        1 0 0
        0 1 0
        0 0 1
    );
    angularMomentum (0 0 0);
    rhoName         rhoInf;
    rhoInf          1000;
    report          on;

    constraints
    {
        maxIteration 500;

        noRotate1
        {
            sixDoFRigidBodyMotionConstraint axis;
            axis            (0 0 1);
        }
        noRotate2
        {
            sixDoFRigidBodyMotionConstraint axis;
            axis            (1 0 0);
        }
        noRotate3
        {
            sixDoFRigidBodyMotionConstraint axis;
            axis            (0 1 0);
        }
        zPlane
        { 
            sixDoFRigidBodyMotionConstraint plane;
            normal          (0 0 1);
        }
    }

    restraints
    {
        verticalSpring1
        {
            sixDoFRigidBodyMotionRestraint linearSpring;

            anchor          (2 0 0);//spring attached point on bottom
            refAttachmentPt (1 0 0.384);//spring attached point on cylinder
            stiffness       2.3225;
            damping         0.109;
            restLength      1;//?
        }
        verticalSpring2
       {
            sixDoFRigidBodyMotionRestraint linearSpring;

            anchor          (0 -2 0);//spring attached point on bottom
            refAttachmentPt (0 -1 0.384);//spring attached point on cylinder
            stiffness       2.3225;
            damping         0.109;
            restLength      1;//?
        }
        verticalSpring3
       {
            sixDoFRigidBodyMotionRestraint linearSpring;

            anchor          (-2 0 0);//spring attached point on bottom
            refAttachmentPt (-1 0 0.384);//spring attached point on cylinder
            stiffness       2.3225;
            damping         0.109;
            restLength      1;//?
        }
        verticalSpring4
       {
            sixDoFRigidBodyMotionRestraint linearSpring;

            anchor          (0 2 0);//spring attached point on bottom
            refAttachmentPt (0 1 0.384);//spring attached point on cylinder
            stiffness       2.3225;
            damping         0.109;
            restLength      1;//?
        }
}


// ************************************************************************* //

Hi Maimouna,

here is my dynamicMeshDict

the only one which I am not sure is the restLength.
I have 4 verticalSpring attached on the cylinder

Best wishes,
Scabbard

[Maimouna]

Dear Scabbard,

many thanks. What about pointDisplacement file and motionU?

[Scabbard]

Originally Posted by Maimouna

Dear Scabbard,

many thanks. What about pointDisplacement file and motionU?

Hi Maimouna,

Do not need to put motionU in to the 0, MotionScale will be automatically generated.

Best wishes,
Scabbard

[Maimouna]

In my case, I deleated pointDisplacement and pointMotionU, but it gives me this error message

Create time

Create mesh for time = 0

Selecting dynamicFvMesh dynamicMotionSolverFvMesh
Selecting motion solver: sixDoFRigidBodyMotion
--> FOAM Warning :
From function dlOpen(const fileName&, const bool)
in file POSIX.C at line 1179
dlopen error : libsixDoFRigidBodyMotion.so: cannot open shared object file: No such file or directory
--> FOAM Warning :
From function dlLibraryTable:pen(const fileName&, const bool)
in file db/dynamicLibrary/dlLibraryTable/dlLibraryTable.C at line 99
could not load "libsixDoFRigidBodyMotion.so"
--> FOAM Warning :
From function dlLibraryTable:pen(const dictionary&, const word&, const TablePtr&)
in file /home/maimouna/OpenFOAM/OpenFOAM-2.2.2/src/OpenFOAM/lnInclude/dlLibraryTableTemplates.C at line 67
Could not open library "libsixDoFRigidBodyMotion.so"



--> FOAM FATAL ERROR:
solver table is empty

From function motionSolver::New(const polyMesh& mesh)
in file motionSolver/motionSolver/motionSolver.C at line 117.

FOAM exiting

What does it mean? What's the problem?

Regards

[Scabbard]

Originally Posted by Maimouna

In my case, I deleated pointDisplacement and pointMotionU, but it gives me this error message

[/COLOR]


What does it mean? What's the problem?

Regards

Hi Maimouna,

which version of OpenFoam are you using?

Best wishes,
Scabbard

[Maimouna]

Dear Scabbard, I'm using OpenFOAM-2.2.2.

[Scabbard]

Originally Posted by Maimouna

Dear Scabbard, I'm using OpenFOAM-2.2.2.

Could you send your case to me, so I can test whether it can run on Openfoam

Best wishes,
Scabbard

[Maimouna]

Dear Scabbard,

I attached you my case.

With million of thanks.

[Scabbard]

Originally Posted by Maimouna

Dear Scabbard,

I attached you my case.

With million of thanks.

Seems like you use anther mesh tools which I do not have.

Best wishes,
Scabbard

[Maimouna]

Dear Scabbard,

what mesh tools you used in your case?

[Scabbard]

Originally Posted by Maimouna

Dear Scabbard,

what mesh tools you used in your case?

Hi Maimouna,

ICEM is the tools which I use, because your polyMesh only have the boundary so
I can not run the case

Best wishes,
Scabbard

[Maimouna]

Dear Scabbard,

my running case is following these steps
./Allclean
./Allprepare
pimpleDyMFoam

[Scabbard]

Originally Posted by Maimouna

Dear Scabbard,

my running case is following these steps
./Allclean
./Allprepare
pimpleDyMFoam

Hi Maimouna

It is seems like I do not have the gmsh.

Best wishes,
Scabbard

[Maimouna]

Hi Maimouna

It is seems like I do not have the gmsh.

Best wishes,
Scabbard

Dear Scabbard,

no worries, I'll try to solve the problem.

Best wishes
Maimouna

[Maimouna]

Dear OpenFOAM user,

I'm trying to let the cylinder moves in both x and y direction. I'm using for that OF230 and pimpleDyMFoam solver. It's moves in x direction itself and y direction itself. Now, I'm trying to keep it moves in x and y direction naturally at the same time. This is my dynamisMeshDict file

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.3.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      dynamicMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dynamicFvMesh      dynamicMotionSolverFvMesh;

motionSolverLibs ("libsixDoFRigidBodyMotion.so");

solver            sixDoFRigidBodyMotion;

sixDoFRigidBodyMotionCoeffs
{
// D = 1m (r=0.5); L=1m
// Volume of cylinder V = D^2*pi/4 * L = 1^2*pi/4 * 1 = 0.25*pi
    patches         (cylinder); 
    innerDistance   0.35;  //??
    outerDistance   2.5;   //??

    mass             9.97;    // m = 9.97 => rho_cylinder = m/V = 12.6946 [kg/m^3] ??only??
    centreOfMass     (4 0 0.5); //was (0 0 0.29); (Overall domain bounding box (0 -4 0) (16 4 1))
    momentOfInertia  (1.4539 1.4539 1.24625);//J = m*(1/12*(3*r^2 + L^2)  1/12*(3*r^2 + L^2)  r^2/2) 
                                            //J = m*(0.14583   0.14583  0.125)
    g               (0 -9.81 0); //was (0 0 -9.81);
    orientation
    (
        1 0 0
        0 1 0
        0 0 1
    );
    angularMomentum (0 0 0);
    rhoName         rhoInf;
    rhoInf          1;  // rho_cylinder is very small for this
    report          on;

    constraints
    {
        maxIteration 500;

        noRotate1
        {
            sixDoFRigidBodyMotionConstraint axis;
            axis            (0 0 1);
        }
        noRotate2
        {
            sixDoFRigidBodyMotionConstraint axis;
            axis            (1 0 0);
        }
        noRotate3
        {
            sixDoFRigidBodyMotionConstraint axis;
            axis            (0 1 0);
        }

       // xLine
       // {
       //     sixDoFRigidBodyMotionConstraint line;
       //     direction       (1 0 0);
       // }
  
       // yLine
       // {
       //     sixDoFRigidBodyMotionConstraint line;
       //     direction       (0 1 0);
       // }

       // zAxis
       // {
       //     sixDoFRigidBodyMotionConstraint axis;
       //     axis            (0 0 1);
       
      //  }

        zPlane
        { 
            sixDoFRigidBodyMotionConstraint plane;
            normal          (0 0 1);
       }
    }

    restraints  //motion is constrained to z=const plane, so linear springs are neaded only for x and y direction.
    {
        horisontalSpring
        {
            sixDoFRigidBodyMotionRestraint linearSpring;

            anchor          (4 0 0.5); // was (0.2 0 0);//?
            refAttachmentPt (4 0 0.5); // was (0.092 0 0.384);//spring attached point on cylinder
            stiffness       4000;//?
            damping         2;//?
            restLength      0;//??
        }

        verticalSpring
      {
            sixDoFRigidBodyMotionRestraint linearSpring;

            anchor          (4 0 0.5);
            refAttachmentPt (4 0 0.5);
            stiffness       4000;//?
            damping         2;//?
            restLength      0;//??
        }


     //spring
      //  {
      //      sixDoFRigidBodyMotionRestraint linearSpring;
 
      //      anchor          (4 0 0.5); // was (0.2 0 0);//?
      //      refAttachmentPt (4 0 0.5); // was (0.092 0 0.384);//spring attached point on cylinder
      //      stiffness       4000; //2.3225;// you should calculate it for your problem
      //      damping         2; //0.001;// this may be 0 or calculated for your problem
     //       restLength      0;
     //   }
 
    }
}


// ************************************************************************* //

Could you please check it for me. What's wrong? How to make cylinder moves in both directions? Are there any constraints problem? What about spring stiffness and damping, are they ok? What else?

Any answer would be welcomed?

Thanks in advanced and regards.

Maimouna

[alirezahd]

Originally Posted by Maimouna

Hi Scabbard,

of course, I need your help. I'm struggling on that for long time. If you don't mind please we can shear your idea and I would be really grateful.

My email address is: may78may@hotmail.com

Best regards
Maimouna

hi dear Maimouna
i did the oscillation on cylinder using OF 2.0.1 everything seems ok but i cant valid my result by comparing the lift coeffs. i've downloaded your case but you said it works on OF versions (2.2.2 and 2.3.0) so unfortunately i couldn't run your file and compare it.
my problem is how to define measure of omega in ponitDisplacement file. according to the papers lock in occurs in 0.9<F<1.1 that F=f0/fs where f0 is the forced oscillation frequency and fs refers to the Strouhal frequency for
the fixed cylinder.
in my case Re=100 u=0.004016 d=0.025 St@Re100=0.165 so fs=0.0265 for F=1 f0=fs then omega is 2*pi*0.0265=0.166
is it right way or not? or problem is in my code?
Thanks and Regards,
alireza heidari.

[Maimouna]

Dear Alireza,

what's the problem in my case? What's the error you get?

Could you please send me your case to have a look? My email: may78may@hotmail.com.

Kind regards

[wyldckat]

Greetings to all!

@Maimouna: It's possible that you've stumbled upon a bug that was present in OpenFOAM 2.3.0 and that might have been already been fixed in 2.3.x. I'm referring to this bug report: http://www.openfoam.org/mantisbt/view.php?id=1284

You might want to try OpenFOAM 2.2.2, since on that bug report it states how a certain feature use to work in 2.2.2, but no longer worked in 2.3.0.

In addition, have a look into the tutorial "mesh/moveDynamicMesh/simpleHarmonicMotion" in 2.2.2. It's a very simple tutorial and it makes it a lot easier to test the parameters for restraints, stiffness and so on. The difference is that this motion is based on gravity+springs only and controlled in the file "0/pointDisplacement".

This tutorial is no longer present in OpenFOAM 2.3... or at least I can't find it ... then again, it might be this tutorial: "multiphase/potentialFreeSurfaceDyMFoam/oscillatingBox" - although it's not controlled in the same way

Best regards,
Bruno

[Maimouna]

Dear Bruno,

lots of thanks for your post. Regarding what you posted #58, I swiched my case from OF-2.3.0 to OF-2.2.2. My pointDisplacement file is

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.2.2                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       pointVectorField;
    location    "0.01";
    object      pointDisplacement;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 1 0 0 0 0 0];

internalField   uniform (0 0 0);

boundaryField
{
    cylinder
    {
        type            sixDoFRigidBodyDisplacement;
        mass            9.97;
        centreOfMass    (4 0 0.5);
        momentOfInertia (1.4539 1.4539 1.24625);
        orientation
        (
            1 0 0
            0 1 0
            0 0 1
        );
        velocity        (0 0 0);
        acceleration    (0 0 0);
        angularMomentum (0 0 0);
        torque          (0 0 0);
        rhoName         rhoInf;
        rhoInf          1;
        g               (0 -9.81 0);
        report          on;
        constraints
        {
            maxIterations   500;

       /* noRotate1
        {
            sixDoFRigidBodyMotionConstraint fixedAxis;
            axis            (0 0 1);
        }

        noRotate2
       {
            sixDoFRigidBodyMotionConstraint fixedAxis;
            axis            (1 0 0);
        }

        noRotate3
        {
            sixDoFRigidBodyMotionConstraint fixedAxis;
            axis            (0 1 0);
        }*/

       fixedLine1
        {
            sixDoFRigidBodyMotionConstraint fixedLine;
            tolerance        1e-9;
            relaxationFactor 0.7;
            fixedLineCoeffs
            {
              refPoint        (4 0 0.5);
              direction       (1 1 0);
            }
         }
  
        fixedLine2
        {
            sixDoFRigidBodyMotionConstraint fixedLine;
            tolerance        1e-9;
            relaxationFactor 0.7;
            fixedLineCoeffs
            {
              refPoint        (4 0 0.5);
              direction       (1 1 0);
            }
        }
     }

        restraints
        {
          horizontalSpring
        {
            sixDoFRigidBodyMotionRestraint linearSpring;

            linearSpringCoeffs

            {
            anchor          (4 0 0.5); // was (0.2 0 0);//?
            refAttachmentPt (4 0 0.5); // was (0.092 0 0.384);//spring attached point on cylinder
            stiffness       4000; //2.3225; 
            damping         2; //0.109; 
            restLength      0;//??
            }

          }
     
        verticalSpring
       {
            sixDoFRigidBodyMotionRestraint linearSpring;

            linearSpringCoeffs
            {
            anchor          (4 0 0.5);
            refAttachmentPt (4 0 0.5);
            stiffness       4000;//?
            damping         2;//?
            restLength      0; //1;//??
           }
       }

       /*axialSpring
            {
                sixDoFRigidBodyMotionRestraint linearAxialAngularSpring;

                linearAxialAngularSpringCoeffs
                {
                    axis            (0 0 1);
                    stiffness       700;
                    damping         0.5;
                    referenceOrientation $orientation;
                }
            }*/
  
     }
        omega         1.14040; 
        amplitude     (0 0.25 0); 
        value           uniform (0 0 0);
    }

    top
    {
        type            empty;
    }

    bottom
    {
        type            empty;
    }

     ".*"
     {
         type            fixedValue;
         value           uniform (0 0 0);
     }
}


// ************************************************************************* //

and my dynamicMeshDict file is

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.2.2                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      motionProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dynamicFvMesh      dynamicMotionSolverFvMesh;

motionSolverLibs ("libfvMotionSolvers.so");

solver            displacementLaplacian;

displacementLaplacianCoeffs
{
    diffusivity       inverseDistance (cylinder);
}


// ************************************************************************* //

Could you please check that two files for me please to make cylinder move as shown in https://www.youtube.com/watch?v=oJNMrFnNaeg. I'm looking for oscillating in both direction. Any idea please? Any additions and/ or corrections in that files?

Thanks and regards.

Maimouna

[wyldckat]

Hi Maimouna,

I'll write this post as a diary of my progress while examining your files and the case at hand. I'm using the case from post #48 as a base, then replaced the files you indicated in the post above. I used OpenFOAM 2.2.x, but should also with 2.2.2... at least I hope so.

1. Unpacked your case and replaced the files.
2. Did some cleaning up, removing backup files "*~" and fixed indentation inside some files.
3. Then opened the files for the tutorial case "mesh/moveDynamicMesh/simpleHarmonicMotion" from OpenFOAM 2.2.x.
4. Then searched for the source code of the linear spring:
   

   find $FOAM_SRC -name "*linearSpring*"

   With that I found the file "linearSpring.H" and this in particular:
   

           //- Anchor point, where the spring is attached to an immovable
           //  object
           point anchor_;
   
           //- Reference point of attachment to the solid body
           point refAttachmentPt_;
   
           //- Spring stiffness coefficient (N/m)
           scalar stiffness_;
   
           //- Damping coefficient (Ns/m)
           scalar damping_;
   
           //- Rest length - length of spring when no forces are applied to it
           scalar restLength_;

   Seems pretty clear what each coefficient stands for.
5. Then I started comparing the "pointDisplacement" field set-up between cases and removed all what seemed excessive to me, since I was still trying to figure things out. Then boosted the U inlet to 100.0 m/s and simplified the BCs to the usual fixed value + zeroGradient inlet and outlet. Oh, and I relaxed a lot the damping and stiffness, so that I could clearly see where the cylinder were floating to. The case I ended up is attached as "freeOscillatingCylinder_v0.1.tar.gz". You'll notice I reduced the time settings to simulate 0.1 s only, saving each 0.01. Quick and dirty results gets us faster through the trial-and-error phase.

I think that now you can start working towards your desired test case. Study the files inside the attached case.
Run the attached case to get a feeling of how my thinking in trying to isolate-and-conquer each setting, one at a time.


Then start from this case to do small changes. First gradually change and test the "horizontalSpring" parameters to suit your case. Then try adding back the "verticalSpring". Then reduce the inlet speed from 100 to 10 and later to 1.

Always run in between changes, to see the results. This way you'll slowly but steadily find how to properly configure your case.

Only when things seem to be working properly, should you start turning on the additional features, such as the functions objects and the long run times.

Best regards,
Bruno